IEEE Transactions on Antennas and Propagation 202107论文速递
1. An Atomic Receiver for AM and FM Radio Communication
用于 AM 和 FM 无线电通信的原子接收器
David Alexander Anderson. Rachel Elizabeth Sapiro. Georg Raithel.
原文链接
“Radio reception relies on antennas for the collection of electromagnetic fields carrying information, and receiver elements for demodulation and retrieval of the transmitted information. Here, we demonstrate an atom-based receiver for AM and FM microwave communication with a 3 dB bandwidth in the baseband of ~100 kHz that provides optical circuit-free field pickup, multiband carrier capability, and inherently high field sensitivity. The atom-based receiver exploits field-sensitive cesium Rydberg vapors in a centimeter-sized glass cell, and electromagnetically induced transparency, a quantum-optical effect, as a readout of baseband signals modulated onto carriers with frequencies ranging over four octaves, from -band to -band. Receiver bandwidth, dynamic range and sideband suppression are characterized, and acquisition of audio waveforms of human vocals demonstrated. The atomic receiver is a valuable receiver technology because it does not require antenna structures and is resilient against electromagnetic interference, while affording multiband operation in a single compact receiving element.
2. Design and Analysis of Dual-Band Implantable Antennas Based on Effective Relative Permittivity Calculation
基于有效相对介电常数计算的双频植入式天线设计与分析
Li-Jie Xu. Zhao-Jun Chu. Lei Zhu. Jin-Peng Xu. Zhu Duan.
原文链接
“This article presents the design and analysis of dual-band implantable antennas based on effective relative permittivity calculation. First, the effective relative permittivity for a microstrip antenna inside lossy tissue is analyzed, helping establish the basis for the design of our proposed dual-band implantable antenna. The antenna operates in 1.4 GHz Wireless Medical Telemetry Service (WMTS) band and 2.45 GHz industrial, scientific, and medical (ISM) band under proper feeding scheme. The lower band with quarter-wavelength resonance is realized by introducing two shorting pins to orthogonal strips. As a disturbance between two arc-shaped tails with open end is introduced, it can achieve circular polarization (CP) radiation property. Meanwhile, the higher band with half-wavelength resonance is realized through the path connecting two asymmetric open-end tails, so as to achieve linear polarization (LP) radiation property. As such, a wide CP bandwidth of 10.38% in WMTS band and a wide impedance bandwidth of 21.3% in ISM band are achieved and in final verified in experiment.
3. Tapered All-Dielectric EBGs With 3-D Additive Manufacturing for High-Gain Resonant-Cavity Antennas
用于高增益谐振腔天线的具有 3D 增材制造技术的锥形全介电 EBG
Cristina Ponti. Paolo Baccarelli. Silvio Ceccuzzi. Giuseppe Schettini.
原文链接
“A resonant-cavity antenna is implemented assembling on an open-ended rectangular waveguide a wideband electromagnetic band gap (EBG), designed as a multilayer. Two different implementations of the multilayer are proposed, labeled as Cases A and B. As to Case A, a high-permittivity layer is embedded between two slabs of low permittivity, whereas a single layer of low permittivity, surrounded by two high-permittivity slabs, is employed in Case B. Successful performances of the broadband behavior are also dependent on the side length of the EBG, that is truncated to small footprints, with an effect of high sidelobe level (SLL). Therefore, grid layouts with nonuniform air holes are proposed for in-plane realization of the dielectric slabs. Their effect in the EBG superstrate is a nonuniform spatial reflectivity, that reduces the SLL keeping a good wideband response. In the EBG manufacturing, both numerically controlled machining techniques and 3-D printing have been employed. 3-D printing has been used for the low permittivity layers, realized in the polylactic acid (PLA) filament, allowing more flexibility in the fabrication of the grid slabs to custom layouts. Results of two antenna prototypes assembling the EBGs, with the parameters of Cases-A and -B and grid layout, to the waveguide source are reported.
4. Finding Optimal Total Active Reflection Coefficient and Realized Gain for Multiport Lossy Antennas
寻找多端口有损天线的最佳总有源反射系数和实现增益
Miloslav Capek. Lukas Jelinek. Michal Masek.
原文链接
“A numerically effective description of the total active reflection coefficient and realized gain is studied for multiport antennas. Material losses are fully considered. The description is based on operators represented in an entire-domain port-mode basis, i.e., on matrices with favorably small dimensions. Optimal performance is investigated, and the conditions on optimal excitation and matching are derived. The solution to the combinatorial problem of optimal ports’ placement and optimal feeding synthesis is also accomplished. Four examples of various complexities are numerically studied, demonstrating the advantages of the proposed method. The final formulas can easily be implemented in existing electromagnetic simulators using an integral equation solver.
5. Directive 2-D Beam Steering by Means of a Multiport Radially Periodic Leaky-Wave Antenna
通过多端口径向周期漏波天线进行定向二维波束控制
Davide Comite. Maksim Kuznetcov. Victoria Gómez-Guillamón Buendía. Symon K. Podilchak. Paolo Baccarelli. Paolo Burghignoli. Alessandro Galli.
原文链接
“A multifed radially periodic two-dimensional leaky-wave antenna is proposed for the generation of a directional beam continuously scanning in elevation by changing the frequency, and over a discrete number of directions in azimuth when activating different elements of the feeding system. The structure is planar and constituted by a circular grounded dielectric slab loaded with microstrip rings, properly positioned around the sources to support the propagation of an angularly directional surface wave over a sector determined by the corresponding activated feeder. This produces a perturbation of the surface wave, resulting in the generation of a directional leaky wave over the aperture, whose complex propagation constant is described by a single fast backward spatial harmonic. The antenna radiation features are numerically investigated in conjunction with the dispersion analysis of the structure, validated through a conventional generalized-pencil-of-function approach. Full-wave simulations have been developed to design a practical feeder, which is constituted by a circular arrangement of commercial coaxial connectors. The proposed multiport antenna is validated by means of measurements performed on a microwave manufactured prototype. The design represents an attractive simple and cost-effective solution to achieve a high-gain beam scanning over the three-dimensional space, alternative to more conventional phased-array design based on cumbersome and lossy feeding networks.
6. 3D Beam Steering End-Fire Helical Antenna With Beamwidth Control Using Plasma Reflectors
使用等离子反射器控制波束宽度的 3D 波束控制端射螺旋天线
Fatemeh Sadeghikia. Mahsa Valipour. Mahmoud Talafi Noghani. Hajar Ja’afar. Ali Karami Horestani.
原文链接
“In this article, a beam steerable antenna based on plasma reflectors is presented. The proposed antenna consists of an axial mode helical antenna surrounded by an array of plasma reflector elements forming a cup-shaped ground. In this configuration, the elements of the reflector array can be individually switched on or off to achieve different radiation characteristics for the helical antenna. Specifically, it is shown that the symmetric activation of a specified number of elements of the plasma array can be used to control the beamwidth of the antenna. Moreover, the plasma reflectors can be asymmetrically configured to steer the endfire beam pattern of the helical antenna in 3-D space. To validate the concept, the proposed antenna is designed and numerically simulated. The simulation results show that using the proposed method, the beamwidth of the proposed antenna can be changed from 37° to 50° while the beam direction can be altered in 3-D space within a solid angle of ±6°. Finally, a prototype of the designed antenna is fabricated and its radiation characteristics for various configurations of the plasma reflectors are measured. Good agreement between the simulation and measurement results validates the proposed method.
7. Misalignment Resilient Anchor-Shaped Antennas in Near-Field Wireless Power Transfer Using Electric and Magnetic Coupling Modes
使用电和磁耦合模式的近场无线电力传输中的未对准弹性锚形天线
Dieff Vital. Shubhendu Bhardwaj.
原文链接
“In this article, we propose a new antenna geometry for near-field magnetoelectric wireless power transfer (ME-WPT) application, where the antenna geometry is found to be resilient to misalignment between the receiving and the transmitting antennas. The proposed geometry is simple to fabricate and is planar, and therefore it can be easily integrated with various platforms suitable for wearable applications. The proposed structure is demonstrated to show improved WPT efficiency under different forms of misalignment between the transmitting and receiving antennas by the virtue of miniaturization and the fringing fields. Specifically, a central bar structure is added in the traditional loop antenna to provide dipole-like and miniaturized performance. Concurrently, a discontinuity in the loop is introduced to enable fringing fields beyond the aperture of the antenna. Investigations are conducted to conclude that a superiority in the performance is associated with these fringing fields. Design-optimization, simulation, and measurement investigations are conducted to estimate the WPT performance under various forms of misalignment. Notably, the proposed structure shows an increase as high as 65% in power transfer efficiency within the range of misalignment considered in this work.
8. Omnidirectional Dual-Polarized Low-Profile Textile Rectenna With Over 50% Efficiency for Sub-μW/cm2 Wearable Power Harvesting
全向双极化薄型纺织整流天线，效率超过 50%，用于亚 μW/cm2 可穿戴功率收集
Mahmoud Wagih. Alex S. Weddell. Steve Beeby.
原文链接
“Despite the recent advances in textile antennas, in complete systems such as a rectenna, the efficiency of fully textile solutions has been over 46% lower than hybrid textile/rigid implementations. This article presents a fully textile rectenna for ultralow-power sub- /cm 2 applications. A dual-polarized omnidirectional low-profile textile antenna is presented. The rectenna is based on a compact inductively matched rectifier. The textile-based rectifier occupies 0.22 cm 2 and achieves a state-of-the-art power conversion efficiency (PCE) of 41.8% at −20 dBm, at 820 MHz, despite its lossy substrate. A triple-band rectifier is then designed and fabricated to show the scalability of the matching approach. The rectifier is characterized using a new figure of merit “average PCE” over a time period while charging a capacitor. Time-varying S-parameters are used to quantify the impact of the capacitor’s charge on the impedance matching. The rectifier directly charges a 1.32 mF capacitor up to 1 V in 0.41 and 4.5 s from 10 and 0 dBm, respectively. Wireless testing of the proposed rectenna demonstrates over 50% and 40% (PCE) below /cm 2 in space and on-body, respectively. The rectenna efficiently receives power from mismatched polarization and with a 360° half-power beamwidth.
9. Design of Novel Printed Filtering Dipole Antennas
新型印刷滤波偶极子天线的设计
Kai-Ran Xiang. Fu-Chang Chen. Qian Tan. Qing-Xin Chu.
原文链接
“A method of designing a printed filtering dipole antenna using codesign of bandpass filter (BPF) and antenna is proposed in this article. The printed dipole antennas consist of two identical arms, which are placed on the opposite sides of the substrate. One arm of the dipole is used to construct the half-wavelength resonator of a typical BPF, and thus filtering and radiation performance can be obtained simultaneously. A third-order filtering dipole antenna is designed and analyzed in detail to demonstrate the codesign method. The measured S 11 of the filtering dipole antenna is less than −11 dB in the range of 0.94–1.094 GHz and the peak gain is 7.8 dBi. To extend this design method, a third-order ±45° dual-polarized filtering dipole antenna is designed and measured. The measured S 11 and S 22 of the ±45° dual-polarized filtering dipole antenna are both less than −11 dB in the range of 0.94–1.08 GHz. Besides, the isolation between them is higher than 20 dB in the passband. The measured radiation patterns show that the dual-polarized filtering dipole antenna would be a potential candidate for base stations.
10. Triple-Radiation Pattern Monopulse Horn Feed With Compact Single-Layer Comparator Network
具有紧凑型单层比较器网络的三重辐射模式单脉冲喇叭馈源
Lucas Polo-López. Juan Córcoles. Jorge A. Ruiz-Cruz. José R. Montejo-Garai. Jesús M. Rebollar.
原文链接
“A monopulse horn feed with a triple-radiation pattern (sum, elevation difference, and azimuthal difference) operating at 35 GHz is presented. The device consists of three main parts: a spline profiled horn, a mode converter that generates the modal field combinations that produce each radiation pattern, and a very compact single-layer monopulse comparator network. Unlike other state-of-the-art designs, the novel feed is based on a triple-radiation pattern horn with a mode converter excited by a comparator network implemented in a single level for improving the compactness and easing quasi-2-D manufacturing. The kernel of this network is a novel 180° H-plane waveguide coupler with in-line ports, which avoids any additional phase compensation in the routing waveguide sections used in other works. The design process of the -band antenna feed is described, and the simulated results for the three radiation patterns and their associated reflection coefficients are presented. The prototyping process is outlined, and the obtained experimental results are compared with the simulated ones showing very good agreement and validating the design process.
11. High-Resolution Implantable Microcoil Antennas for Blood-Vessel Imaging in High-Field MRIs
用于高场 MRI 中血管成像的高分辨率可植入微线圈天线
Sana Ullah. Hyoungsuk Yoo.
原文链接
“This article presents rectangular and circular intravascular receive-only (Rx) open interior microcoils (MCs) for blood-vessel and brain-aneurysm imaging with two different magnetic resonance imaging (MRI) frequencies (128 and 298 MHz for field strengths 3 and 7 T, respectively). The proposed Rx MCs have a miniature volume of 4.92 mm 3 . They offer a wider bandwidth, homogenous radio frequency (RF) receptivity, a high signal-to-noise ratio, and better vessel imaging than that offered by state-of-the-art MCs. In addition, they have open interiors that enable uninterrupted blood flow during MRI scanning and reduce motion artifacts. The proposed MCs were used to mimic different blood vessels of the brain, heart, neck, and kidneys in a realistic human voxel-based Duke model. We compared the reception efficiency ( ) and the sum of strengths (i.e., ) in the region of interest (ROI) for the combined approach involving the birdcage (BC)/surface coil and the MC for various coil arrangements. The proposed MCs were fabricated and integrated with the 3-D-printed blood-vessel model. The simulation results indicate that the proposed MCs achieved the improvements of 72% and 75% in and , respectively, in the selected ROI (the blood vessel). Moreover, the MR images obtained by the proposed MCs exhibited high sensitivity of the blood signal and offered selective imaging of the arterial walls. According to the results, the proposed Rx MCs can be applied to perform intravascular imaging of smaller blood vessels.
12. Dual-Band Linearly and Circularly Polarized Unidirectional Hybrid Loop/Magnetoelectric Dipole Antenna With Single Feeding
双频线性和圆极化单向混合环路/磁电偶极天线，单馈
Changfei Zhou. Shanshan Yuan. Hui Li. Min Li.
原文链接
“A dual-band linearly polarized (LP) and circularly polarized (CP) unidirectional hybrid antenna is proposed in this article. The antenna consists of a cross slot antenna (CSA), a pair of vertical and horizontal metal plates, two side walls, and a cavity reflector, fed by a simple single feeding structure. In the lower frequency band, a loop antenna operating in mode is formed by the ground of the CSA, a pair of horizontal plates, and two side walls, to generate the LP radiation. In the higher frequency band, the cross slot works as a magnetic dipole (M-dipole), while the horizontal plates work as an electric dipole (E-dipole). With the appropriate combination, the magnetoelectric (ME) dipole produces an inherent 90° phase difference for the two orthogonal -fields to achieve CP radiation. The modes of the M- and E-dipoles are excited to realize the wideband CP bandwidth. Simulation and measurement are used to study and design the hybrid antenna. The results show that the proposed antenna has an impedance bandwidth (IMBW) of 2.38–2.50 GHz (0.12 GHz, 4.9%) for the LP radiation, and an IMBW of 4.63–7.37 GHz (2.74 GHz, 45.7%) and 3 dB axial ratio bandwidth (ARBW) of 4.10–6.60 GHz (2.5 GHz, 46.7%) for the CP radiation. The radiation patterns at dual bands are stable toward the broadside, having peak gains of 5.75 dBi and 7.53 dBic within the low and high frequency bands.
13. RESHAPE: A Liquid Metal-Based Reshapable Aperture for Compound Frequency, Pattern, and Polarization Reconfiguration
RESHAPE：用于复合频率、方向图和极化重构的基于液态金属的可整形孔径
Vivek T. Bharambe. Jinwoo Ma. Michael D. Dickey. Jacob J. Adams.
原文链接
“We demonstrate a single-feed planar antenna capable of independently reconfiguring its operating frequency, radiation pattern, and polarization using stretchable, encapsulated liquid-metal (LM) parasitic elements. The LM is contained within elastomeric fibers that can be mechanically translated, stretched, or relaxed to alter the position or length of each conducting element on a 2-D surface, physically reshaping the metal on the antenna aperture. This eliminates several practical challenges associated with fluidic actuation of LM and makes the actuation scheme much faster and more reliable than other recent approaches. Using this scheme, the reshapable aperture (RESHAPE) design supports continuously reconfigurable operating frequencies from 2.45 to 6.5 GHz while supporting either linear
-
or -polarizations. At the same time, the radiation pattern can also be reconfigured in all planes, over a continuous range, to a maximum of ±45° away from the broadside direction for most frequencies. For all these possible states, the antenna maintains a 2:1 VSWR and a total efficiency of >60%. We explain the operation of the design at several frequencies, analyze the coverage area, and present measurements of a fabricated prototype.
14. Millimeter-Wave Near-Field-Focused Full 2-D Frequency Scanning Antenna Array With Height-Modulated-Ridge Waveguide
具有高度调制脊波导的毫米波近场聚焦全二维频率扫描天线阵列
Ya Fei Wu. Yu Jian Cheng. Shi Sen Yao. Yong Fan.
原文链接
“A millimeter-wave near-field-focused (NFF) full 2-D frequency-scanning antenna array is presented in this article. The proposed antenna is achieved by combining an NFF ridged-waveguide slot array with a double-layer folded focused progressive feeding network. The linear ridged-waveguide slot array antenna is designed with a height-modulated ridge to focus on the power in one direction. The folded feeding line with different length is used to generate the desired focused phase and frequency-dependent progressive phase shift in the other direction. In this case, as the working frequency is swept in the considered range, the inherent frequency-dependent behavior of the linear NFF leaky-wave antenna (LWA) allows a single-scanning sweep in one direction, whereas the focused progressive feeding network ensures multiple-scanning sweeps in the other direction. A full 2-D electronic scanning with no coverage blindness in the scanning area is achieved. To the best of our knowledge, the proposed NFF antenna array is the first design to achieve the full 2-D scanning focus in the near-field (NF) region only by sweeping the frequency, which means that the testing information in the NF region can be directly obtained with a certain band of frequency. This type of antenna is a good candidate in NF fast-scanning applications, e.g., electromagnetic imaging/detecting systems.
15. Wideband and Low Cross-Polarization Transmitarray Using 1 Bit Magnetoelectric Dipole Elements
使用 1 位磁电偶极子元件的宽带和低交叉极化发射阵列
Fan Wu. Jingxue Wang. Rong Lu. Xiaoyue Xia. Wei Hong. Kwai-Man Luk.
原文链接
“The application of magnetoelectric (ME) dipole to achieve wideband and low cross-polarization transmitarray design is presented in this article. First, a novel meandering-probe-fed ME dipole that exhibits a wideband matching, central feeding configuration, and symmetrical antenna structure is developed. These preferred features are borrowed to address the narrowband and potential element-displacement issues in 1 bit transmitarray element design. Numerical simulations of the proposed 1 bit ME-dipole transmitarray element show a wide 1 dB insertion-loss bandwidth of 47% and a low cross-polarization level of −40 dB. Measured results of the transmitarray designed using the proposed ME-dipole elements indicate an operating bandwidth of 47% and a cross-polarization discrimination (XPD) around 35 dB. In addition, a dual-layer phase compensation scheme for cross-polarization synthesis is described. The effectiveness of this method is demonstrated with a cross-polarization cancelation scheme that further improves the measured XPD to 40 dB. The proposed transmitarrays show advantages of remarkable bandwidth, low cross-polarization, and comparatively high aperture efficiency over most reported 1 bit designs.
16. Wideband Circularly Polarized Planar Antenna Array for 5G Millimeter-Wave Applications
用于 5G 毫米波应用的宽带圆极化平面天线阵列
Yang Cheng. Yuandan Dong.
原文链接
“A novel wideband circularly polarized (CP) planar array antenna is proposed in this article for the upcoming fifth-generation (5G) millimeter-wave (mm-wave) applications. The antenna element is fed by a slot etched on the substrate integrated waveguide (SIW) for convenient integration. It consists of two additional semicircle patches and two suspend metal posts which are working as the newly proposed polarizers for broadband CP operation. The combined patch, post, and slot generate totally four CP modes which greatly expand the antenna 3 dB axial ratio (AR) bandwidth. The antenna operating mechanism and the design procedure are illustrated in detail. The simulated results for the antenna element show an AR bandwidth of 41.28% from 25.66 to 39.01 GHz, an impedance bandwidth of wider than 44.62% from 24.41 to 38.43 GHz, and a gain of 7.25 ± 1 dBic over the frequency band. The antenna shows a stable pattern and wide AR/impedance overlapping bandwidth (25.66–38.43 GHz), which covers most of the current 5G mm-wave bands. To enhance the antenna gain for practical application, a planar antenna array fed by a fully incorporated SIW network is designed, fabricated, and measured. The measured results for the array demonstrate an AR bandwidth of 36.51% from 25.3 to 36.6 GHz, an impedance bandwidth of 40.21% from 24.42 to 36.71 GHz, and a peak gain of 19 dBic. The proposed antenna features a novel broadband CP working principle, low profile, and good radiation performance, which is well suited for 5G mm-wave applications.
17. Sparse Array Beamforming Design for Coherently Distributed Sources
相干分布源的稀疏阵列波束成形设计
Zhi Zheng. Yueping Fu. Wen-Qin Wang.
原文链接
“Recently, nonstructured sparse array designs have attracted wide interest due to their capability of providing optimum performance for environment-dependent adaptive beamforming. In this article, we develop a sparse array design approach for adaptive beamforming in the presence of spatially coherently distributed (CD) sources. The proposed approach formulates the design problem via maximizing the output signal-to-interference-plus-noise ratio (SINR), but it exploits the generalized array manifold of CD sources. Moreover, sequential convex programming is utilized to convert the nonconvex optimization problem into a series of convex subproblems. We also analyze the impact of source distributed shape on optimum array configuration and theoretically prove that when the CD sources are Gaussian-shaped, the uniform linear array (ULA) is exactly the optimum array configuration. The resulting optimum sparse arrays yield higher output SINR and better-shaped beampattern than the structured sparse arrays. Numerical results verify the superiority of the optimum sparse arrays obtained by the proposed approach over the structured sparse arrays.
18. A Dual-Polarized Planar Antenna Array Differentially-Fed by Orthomode Transducer
正交模式传感器差分馈电的双极化平面天线阵列
Qingling Yang. Steven Gao. Qi Luo. Lehu Wen. Xiaofei Ren. Jian Wu. Yong-Ling Ban. Xue-Xia Yang.
原文链接
“This article presents a new design of a differentially fed substrate integrated planar antenna array with dual-polarization. Compared with the traditional dual-polarized antenna arrays, the proposed array antenna has the advantages of simple configuration, high cross-polarization discrimination (XPD), and high gain. The -element subarray design with a via-loaded crossover structure is used, which reduces the complexity of the array antenna. The operation bandwidth is improved by generating three resonances in the subarray. An antenna array is designed, prototyped, and tested to exemplify its potential applications in large dual-polarized antenna arrays. A planar orthomode transducer is used to achieve differential excitation for the antenna array. The measured results show that the proposed antenna array has an impedance bandwidth of 19.2–20.7 GHz for dB and port isolation higher than 20 dB. The array antenna exhibits a high XPD of 43 dB and a flat gain of about 22.2 dBi within the bandwidth.
19. A Self-Calibration Method for 5G Full-Digital TDD Beamforming Systems Using an Embedded Transmission Line
一种使用嵌入式传输线的 5G 全数字 TDD 波束成形系统的自校准方法
Chong Guo. Ling Tian. Zhi Hao Jiang. Wei Hong.
原文链接
“In this article, a self-calibration method for 5G full-digital time-division duplexing (TDD) beamforming systems is proposed and demonstrated, including the self-calibration for both the transmit (Tx) and receive (Rx) channels. By incorporating an embedded transmission line (ETL) in the antenna array that weakly couples with all the radiating elements, the relative magnitude and phase of each Tx/Rx channel can be obtained with the proposed calibration procedure. Comparing with conventional self-calibration methods, the proposed approach requires simpler hardware and reduced calibration time. As a proof-of-concept example, a full-digital TDD beamforming array operating at 3.5 GHz with an ETL is fabricated for validation. To further evaluate the accuracy of the calibration data, the “stepped null” calibration was conducted by the over-the-air (OTA) measurement. It is shown that the root mean square (rms) phase and magnitude errors of the calibration results for the Tx and Rx channels are 5.8°/0.84 and 6.3°/0.91 dB, respectively, which are sufficiently accurate for beamforming in 5G communication systems.
20. Single-Point Array Response Control: An Efficient Beampattern Synthesis Approach Based on the Maximum Magnitude Response Principle
单点阵列响应控制：一种基于最大幅度响应原理的高效波束图合成方法
Xiaoyu Ai. Lu Gan.
原文链接
“This article considers the beampattern synthesis problem, and a single-point array response control (SPARC) algorithm is presented to adjust the array response at an arbitrary direction. Based on the theoretical analysis, it is found that the adaptive array theory-based optimal weight vector is a linear combination of the signal steering vector and the interference steering vector multiplied by a complex factor, and that the complex factor determines the array response at the interference direction. Inspired by this observation, the SPARC algorithm is presented to achieve quiescent pattern control. In contrast to other array response control-based pattern synthesis techniques, the SPARC algorithm obtains a deterministic expression of the complex factor after maximizing the magnitude response at the main-beam direction, and the closed-form expression of the designed weight vector is devised. Because of different pattern constraints in focused and shaped beampatterns, two low-complexity pattern synthesis schemes are presented employing the SPARC algorithm in an iterative manner. Moreover, the parameter selection principle of the SPARC and its comparison with other pattern synthesis methods are discussed. Simulation results show the effectiveness of the SPARC algorithm and the efficiency of the beampattern synthesis schemes.
21. Transmit–Receive Parabolic Reflectarray to Generate Two Beams per Feed for Multispot Satellite Antennas in Ka-Band
发射-接收抛物面反射阵列为 Ka 波段多点卫星天线的每个馈源生成两个波束
Daniel Martinez-de-Rioja. Eduardo Martinez-de-Rioja. Yolanda Rodriguez-Vaqueiro. Jose A. Encinar. Antonio Pino. Marcos Arias. Giovanni Toso.
原文链接
“This contribution describes the design of a multibeam parabolic reflectarray to produce two adjacent beams per feed in orthogonal circular polarization (CP) simultaneously at the transmission (Tx) and reception (Rx) frequencies in the Ka -band. The variable rotation technique (VRT) has been applied to the reflectarray cells based on two types of resonant elements, which makes it possible to provide orthogonal beams at Tx and Rx, as well as to implement an in-band optimization procedure to reduce the cross-polarization. A 90 cm parabolic reflectarray has been designed, manufactured, and tested to produce multiple adjacent beams in RHCP and LHCP at both 20 and 30 GHz. The results are satisfactory and validate the concept of generating two spaced beams in the orthogonal CP by a single feed, changing the polarization of the beam between Tx and Rx. This concept can be suitable for multispot satellites in the Ka -band, enabling to halve the number of onboard antennas and feeds.
22. Millimeter-Wave Huygens’ Transmit Arrays Based on Coupled Metallic Resonators
基于耦合金属谐振器的毫米波惠更斯发射阵列
Soichi Sakurai. João G. Nizer Rahmeier. Takashi Tomura. Jiro Hirokawa. Shulabh Gupta.
原文链接
“A novel Huygens’ transmit array (TA) is proposed based on a coupled-resonator approach to demonstrate millimeter-wave (mm-Wave) beamforming for linear polarization. The proposed structure is simple and compatible with standard printed circuit board (PCB) processes and utilizes a single dielectric substrate only. It is shown that by engineering the geometrical dimensions of the resonator, its electric (even-mode) and magnetic (odd-mode) resonances are excited in a balanced manner to achieve zero backscattering in a large bandwidth. This operation principle of the proposed Huygens’ cell is explained in detail using both an insightful equivalent circuit model, as well as full-wave eigenmode analysis. Next, the proposed Huygens’ cell is placed on top of a high-gain 2-D slot-array antenna, in its near field, to engineer its aperture field distribution. Several TA prototypes designed around the 60 GHz frequency band are demonstrated and experimentally characterized in both their near and far fields, to achieve difference pattern generation, beam expansion, and beam steering as application examples, in addition to a uniform surface demonstrating its low-loss performance.
23. Origami-Inspired Radiation Pattern and Shape Reconfigurable Dipole Array Antenna at C-Band for CubeSat Applications
用于立方体卫星应用的 C 波段折纸辐射模式和形状可重构偶极子阵列天线
Myeongha Hwang. Gyoungdeuk Kim. Sangkil Kim. Nathan Seongheon Jeong.
原文链接
“This article presents an antenna structure with a reconfigurable pattern and polarization for CubeSat applications. The proposed antenna is based on spatial-mapping origami theory and consists of a center-fed four-way Gysel power divider, delay lines, inside lamina emergent torsion (LET) joints, and four thick planar dipole antennas. The LET joints are used to distribute the mechanical stress of a rigid planar material to form a flexible planar spring structure. The proposed antenna has monopole-like omnidirectional linearly polarized gain patterns in planar mode. Its gain value is about 0.5 dBi at 5.8 GHz. In folded mode, the antenna has about a circularly polarized gain value of about 8.07 dBic and broadside radiation patterns. The measured cross-polarization suppression ratio is about 25 dB, and the axial ratio (AR) value is 1.13 dB at 5.8 GHz. The size of the antenna in planar mode with a cross-shape is mm 3 , and its size is in folded mode is mm 3 . The size of the antenna in inactive mode is mm 3 , and its total weight is only 4.73 g.
24. Efficient Analysis of Wave Propagation in Metasurface Arrays Based on Eigenvalue Perturbation
基于特征值扰动的超表面阵列中波传播的有效分析
Peyman Abdipour. Amir Nader Askarpour. Andrea Alù.
原文链接
“We explore two types of eigenvalue perturbations to analyze the dispersion features of periodic arrays of metasurfaces (MSs) for arbitrary propagation angles. The perturbations describe the dependence of the dispersion upon physical quantities with closed-form expressions, which result in a deeper understanding and physical insights into the dependence of the effective parameters of the stack on the MS properties. Our analytical theory is applied to three representative examples of periodic structures containing linear MSs. Due to the underlying symmetries in the considered examples, the perturbation results are further simplified, shedding light into interesting opportunities offered by MS arrays for the manipulation of electromagnetic wave propagation.
25. Demonstration of a Reflectarray With Near-Field Amplitude and Phase Constraints as Compact Antenna Test Range Probe for 5G New Radio Devices
演示具有近场幅度和相位约束的反射阵列作为 5G 新无线电设备的紧凑型天线测试范围探针
Álvaro F. Vaquero. Manuel Arrebola. Marcos Rodriguez Pino. Rafael Florencio. José A. Encinar.
原文链接
“In this work, a reflectarray is proposed to be used as a probe of reduced and portable compact-antenna-test range for 5G new radio devices. The reflectarray works at 28 GHz and produces a quiet zone in the near-field region of the antenna. Considering that the quiet zone specifications are established in terms of the amplitude and phase ripple, a synthesis technique is presented to optimize the near field in the Fresnel region of a reflectarray with amplitude and phase constraints. The proposed technique is based on the generalized intersection approach using the Levenberg–Marquardt algorithm as its backward projector obtaining a novel technique in near-field synthesis. This technique is applied to improve the quiet zone radiated by the proposed reflectarray, overcoming the amplitude and phase limitations of the initial configuration. The solution provided by this process is used to design and manufacture a reflectarray based on a three-parallel-dipole cell. Finally, the prototype is measured in a near-field planar range facility in order to evaluate the radiated quiet zone and demonstrate the methodology. The prototype satisfies the tight requirements in amplitude and phase, obtaining promising results.
26. True-Time-Delay Mechanical Phase Shifter in Gap Waveguide Technology for Slotted Waveguide Arrays in Ka-Band
用于 Ka 波段开槽波导阵列的间隙波导技术中的真时延迟机械移相器
Daniel Sánchez-Escuderos. Jose Ignacio Herranz-Herruzo. Miguel Ferrando-Rocher. Alejandro Valero-Nogueira.
原文链接
“This article proposes a novel all-metal mechanical phase shifter in gap waveguide technology. The phase shifter is aimed at providing beam-scanning capabilities to conventional slot array antennas along the elevation plane. To validate experimentally the beam-steering functionality, a slot-array antenna has been designed and fabricated, along with the phase-shifting mechanism. The whole antenna consists of two pieces: a lower rotatable block, which changes the length of concentric groove gap waveguides, and an upper fixed block, where the slot-array antenna is placed. Experimental results validate the proposed concept, having obtained steering angles of up to 25°, with gain levels around 20 dBi with an antenna efficiency close to 90%. A reflection coefficient below −10 dB is achieved for a wide range of rotation angles from 29.5 to 30.5 GHz. The proposed phase shifter is completely scalable to any array size and its true-time-delay nature enables wide steering ranges for closely-spaced slot arrays with wideband radiation performance.
27. Study on an Accurate and Efficient Design Method of Resonant FSSs Based on the Macro-Model of Units in the Basic Strip-Gap FSS
基于基本带隙FSS单元宏观模型的谐振FSS精确高效设计方法研究
Zhixin Yao. Shaoqiu Xiao. Bing-Zhong Wang.
原文链接
“An accurate and efficient design method for resonant frequency selective surfaces (FSSs) based on the macro-model of units in the basic strip-gap FSS is proposed. Several variables are introduced in the formulas to improve the accuracy of computation. Without dielectric substrate, two effective widths are introduced in the calculation of equivalent L and C due to the current inhomogeneity caused by the gap. Novel equivalent circuit (EC) formulas are proposed after full-wave simulation and parameter fitting. Furthermore, with substrate, another two variables, the effective permittivity for inductance and capacitance, are introduced with detailed calculation equations. The results obtained by simulation and EC calculation show that not only the resonance frequencies but also the frequency responses over a wide frequency band are found to be in reasonable agreement, when the wavelength of the operating frequency is smaller than the period. For verification of complex structures and actual application, two absorbers based on cross dipole and square loop FSSs, respectively, are proposed. Good agreement is gained between the measurements of a fabricated sample working from 2.03 to 9.36 GHz, and the results obtained by EC calculation and simulation. The results verify that it is feasible to use this method in the study of more complex and novel structures which are based on resonant FSSs.
28. An Advanced Eigenvector-Correlation-Based Tracking Method for Characteristic Modes
一种先进的基于特征向量相关的特征模式跟踪方法
Xiang Jie Chen. Yong Mei Pan. Guo Dong Su.
原文链接
“An advanced characteristic mode tracking method is investigated in this article. The tracking method is based on the eigenvector correlation, and a novel tracking error correction algorithm (TECA) is proposed to solve the challenging issues caused by the mode swapping and the mode degeneracy. As the core of the modal tracking method, the TECA can quickly find out the cross-mode pairs according to the eigenvalue differences among different modes, identify the wrongly mapped modes using the eigenvector correlation, and finally correct all the possible tracking errors. The detailed process of each step is described and discussed. In addition, the characteristic modes of two classical fractal antenna structures are investigated for validation. It has been shown that the modes including the swapped modes and degenerated modes are all tracked correctly, verifying the modal tracking method is reliable and efficient. Compared with the previous approaches, the proposed method is not subject to the number of tracked modes and the magnitude of eigenvalue. Also, it requires less computational time. Moreover, the sensitivity to the sizes of frequency step and mesh is reduced to some extent.
29. Active Self-Tuning Metasurface With Enhanced Absorbing Frequency Range for Suppression of High-Power Surface Currents
具有增强吸收频率范围的主动自调谐超表面，用于抑制高功率表面电流
Sanghoon Kim. Aobo Li. Jiyeon Lee. Daniel F. Sievenpiper.
原文链接
“We demonstrate a unique metamaterial surface that actively tunes its resonance frequency to match the frequency of incident electromagnetic waves, providing a broadband self-tuning absorber. The metasurface is constructed with nonlinear circuit components and is capable of detecting the incoming signals and adapting its resonant frequency without any external control. The fabricated prototype achieves 70% of −3 dB fractional frequency range compared with the intrinsic limit of around 5% for a passive absorbing surface of the same thickness. Its performance is experimentally verified by measuring absorption as a function of frequency with the self-tuning circuits turned on or off to demonstrate the self-tuning capability and the increase in the absorption frequency range. The measurements were performed for both TM and TE polarizations and various oblique incident angles. The proposed metasurface has a threshold power level for the absorption of incident waves and only absorbs high-power interfering signals while allowing small signals, such as for communications.
30. A Frequency-Selective Surface Rasorber Based on Four Functional Layers
基于四个功能层的频率选择性表面吸收器
Hang Ye. Jianfeng Wei. Li Lin. Fucheng Liu. Ling Miao. Shaowei Bie. Jianjun Jiang.
原文链接
“In this article, a frequency-selective surface (FSS) rasorber based on four metallic FSS functional layers is proposed. The rasorber consists of two metallic FSS absorption layers, two metallic FSS transmission layers, and four corresponding dielectric isolation layers. The top absorption layer and third absorption layer are applied to generate a wide absorption band at high frequency and low frequency, respectively. The second and bottom transmission layers are adopted to generate a low-pass transmission band and bandpass transmission band, respectively. The multilayer structure of the rasorber guarantees the great span, broad bandwidth, and stable scattering characteristics. Moreover, we adopt the equivalent circuit model (ECM), surface current distribution, and loss distribution to comprehend the physical mechanism of the rasorber. The simulated results show that the transmission is −0.67 dB at 6.5 GHz, and the reflection below −10 dB ranges 1.5–4.6 and 9.2–13.7 GHz. To validate our design, we fabricated and measured the prototypes, and the measurement results show reasonable agreement with the simulated results.
31. Polarization Insensitive and Transparent Frequency Selective Surface for Dual Band GSM Shielding
用于双频段 GSM 屏蔽的偏振不敏感和透明频率选择表面
Yiming Yang. Weiwei Li. Khaled N. Salama. Atif Shamim.
原文链接
“This article proposes a single-layer, dual-band, optically transparent frequency-selective surface (FSS) for GSM shielding. The design evolves from a fractal cross dipole to achieve dual-band response, polarization insensitivity, and wide angle of incidence stability with a miniaturized size. A two-axis symmetric structure helps to provide a stable frequency response for incident waves with different polarization angles up to 60°. Capacitive loading further reduces the unit size and extends the maximum stable incident angle. The working mechanism of the design has been explained through an equivalent lumped element circuit model (ECM), which provides a generic approach to retune or optimize the design for another frequency band. Both the full-wave EM and circuit simulations are in good agreement. A prototype has been realized by screen printing a custom silver nanowire (Ag NW)-based transparent ink on a flexible polymer substrate. A decent reflection performance has been achieved from 0.71 to 1.25 GHz and from 1.73 to 2.16 GHz in measurements, which are consistent with the simulations. Optical measurements reveal a transparency of 81.6%. Printed FSS is completely flexible, and the performance does not deteriorate after bent or rolled up conditions. Field testing on a glass box demonstrates decent shielding from the incoming GSM signals. The highly transparent and flexible nature of the FSS structure makes it suitable for mounting on glass windows of cars or home environments for EM shielding purposes.
32. Surface Integral Equation Method for Soft-and-Hard/DB Boundary Condition
软硬/DB边界条件的表面积分方程法
Beibei Kong. Pasi Ylä-Oijala. Ari Sihvola.
原文链接
“A surface integral equation (SIE) method is developed to analyze electromagnetic scattering by 3-D objects with soft-and-hard/DB (SHDB) boundary conditions. The SHDB boundary condition is a generalization of the soft-and-hard (SH) and DB boundary conditions that associate the normal and tangential field components on the boundary. In the developed method, the SHDB boundary condition is expressed in vector form that allows combining it with the tangential field integral equations. The obtained equations can be discretized with the standard method of moments (MoM) using the Rao–Wilton–Glisson (RWG) functions. Different combinations of the integral equations and boundary conditions are derived, and their numerical performance is studied and compared. It is demonstrated with numerical experiments that a much more stable system is obtained by considering the boundary conditions as extra equations, rather than integrating them into the SIEs. The solutions of the proposed nonsquare integral equation are verified with the physical optics approximations.
33. An Improved Subspace-Regularized DBIM-MLGFIM Method for Three-Dimensional Inverse Scattering Problems
一种求解三维逆散射问题的改进子空间正则化DBIM-MLGFIM方法
Peng Zhao. Linchun Liu. Kuiwen Xu. Xiuzhu Ye. Shichang Chen. Gaofeng Wang. Chi Hou Chan.
原文链接
“The repetitive computation of the forward problem in distorted Born iterative method (DBIM)-type inversion method is time-consuming and memory-costly, especially in dealing with 3-D inverse scattering problem. An improved subspace-regularized DBIM is proposed for the efficient solution of the 3-D inverse problem, which introduces the multilevel Green’s function interpolation method (MLGFIM) to accelerate the computation of the forward problem. In order to stabilize the inversion, an improved subspace-regularized DBIM is used with one new subspace-regularized induced current term in the cost function in virtue of truncated singular value decomposition (TSVD). To further reduce the computation burden, the incident field induced with updated inhomogeneous background medium is used approximately as the total field in the cost function, which saves one forward solver calculation in each iteration. Besides, the resource-intensive multiplication of inhomogeneous Green’s function can be avoided, which further improves the efficiency. Three numerical and two Fresnel experimental examples are given to demonstrate both the efficiency of the forward solver and the accuracy of the inversion algorithm.
34. Attributed Scattering Center Extraction With Genetic Algorithm
基于遗传算法的属性散射中心提取
Maoqiang Jing. Guo Zhang.
原文链接
“An attributed scattering center (ASC) model provides concise and physically relevant features for complex targets and plays an important role in inverse scattering problems. Extracting ASC features from a radar image is designed to solve a highly nonlinear and nonconvex optimization problem, which requires an accurate yet complex parameter initialization process and generates intensive computation and storage cost. This article presents an ASC feature extraction method with a genetic algorithm (GA) (AFEM-GA). The proposed AFEM-GA utilizes an improved real-coded GA to search for the global optimum for each ASC feature in the radar frequency-aspect angle domain in parallel, without complex parameter initialization and with low computation and storage costs. Moreover, an improved relaxation algorithm is also proposed for multiple ASC feature extractions to avoid error accumulation. Experiments based on both numerical computed data and real data verify the accuracy and robustness of the proposed AFEM-GA and show its potential in radar image interpretation.
35. Scattering Prediction of Target Above Layered Rough Surface Based on Time-Domain Ray Tracing Modeling
基于时域射线追踪建模的分层粗糙表面上目标散射预测
Rui Wang. Guangbin Guo. Zhiyuan He. Lixin Guo.
原文链接
“In the past, most of the transient electromagnetic (EM) analyses focused on the scattering from the target. The transient scattering from rough surface was rarely studied, especially for the layered rough surface. When the target is above the rough surface, it needs to solve the composite transient scattering from the rough surface and the target above it. In this article, we mainly focus on the time-domain (TD) analysis for transient scattering from the target and layered rough surface based on time-domain ray tracing (TDRT) modeling. Applying geometrical optics (GO), the multiple bounces of the transient EM waves between layered rough surfaces and target are traced to obtain the incident field of the irradiated surfaces. Then considering the particularity of the layered rough surface, we modify TD Gordon integral and reduce the TD physical optics (TDPO) integral to closed-form expressions to improve the computing efficiency. To demonstrate the efficiency and accuracy of the proposed algorithm, the transient scattering simulations of the composite model involving target and layered rough surface are compared with frequency-domain ray tracing (FDRT) with inverse fast Fourier transform (IFFT), as well as the results obtained by the multilevel fast multipole algorithm (MLFMA) of FEKO in conjunction with IFFT (IFFT-MLFMA). The characteristics of transient scattering from the composite model are further studied to show the physical phenomenon of scattering mechanisms. Specifically, the transient scattering from the composite model for different parameters is simulated for sensitivity investigation of the transient scattering to the variations in the related parameters.
36. A Multifunctional Frequency-Selective Polarization Converter for Broadband Backward-Scattering Reduction
一种用于减少宽带后向散射的多功能选频偏振转换器
Lingling Wang. Shaobin Liu. Xiangkun Kong. Haifeng Zhang. Qiming Yu. Yongdiao Wen. Dongdong Wang.
原文链接
“A novel dual-polarized frequency-selective polarization converter (FSPC) with low-backward scattering is proposed by combining a bandpass frequency-selective surface (FSS) with a polarization converter. The FSPC, comprised of the top polarization conversion layer and the bottom multilayer bandpass FSS, is formed by introducing two polarization converter bands on both sides of the broadband passband. The four-port equivalent circuit model cascading FSS and polarization converter is proposed and investigated. It is numerically demonstrated that a flat 1 dB transmission window can be obtained from 8.5 to 11 GHz with a 25.6% fractional bandwidth (FBW), and the bandwidth of reflection below −10 dB is up to 92% from 5.6 to 15.13 GHz. Moreover, the proposed device can achieve two polarization conversion bands (5.66–6.9 and 12.8–15.2 GHz) with the polarization conversion ratio over 90%. Besides, by arranging the proposed structure in a checkerboard-like distribution, the backward scattering energy can be reduced in a wide frequency band ranging from 4.5 to 16 GHz. Both simulation and experimental results are in good agreement, which demonstrates our design strategy. Compared with the conventional polarization converters, the proposed design presents an extra frequency-selective performance and, hence, can be a great substitute for the frequency-selective rasorber (FSR).
37. Volume Equivalent SBR Method for Electromagnetic Scattering of Dielectric and Composite Objects
用于介电和复合物体电磁散射的体积等效 SBR 方法
Yuan Huang. Zhiqin Zhao. Xianjin Li. Zaiping Nie. Qing-Huo Liu.
原文链接
“A volume equivalent shooting and bouncing ray (VESBR) method is proposed to analyze the electromagnetic scattering of dielectric and composite objects with thick dielectric medium. Different from traditional high-frequency methods which utilize surface sources, this VESBR considers the propagation of electromagnetic waves inside the dielectric media and introduces volume equivalent sources to calculate the scattering fields. Compared with traditional methods, two different problems need to be solved in this method, i.e., the ray tracing on dielectric boundary and the volume integral in ray tube. For ray tracing process, a refined formula is proposed to acquire the information of reflection waves and transmission waves on dielectric boundary. For volume integral in ray tube, the integral is transformed to five surface integrals based on Gauss’s law. The simulations of four cases show that the results of VESBR agree well with those of surface integral equation (SIE), while the computation time and the required memory of VESBR are much less than those of SIE.
38. An Improved Deep Learning Scheme for Solving 2-D and 3-D Inverse Scattering Problems
用于解决 2-D 和 3-D 逆散射问题的改进深度学习方案
Yulong Zhou. Yu Zhong. Zhun Wei. Tiantian Yin. Xudong Chen.
原文链接
“Reconstructing the exact electromagnetic property of unknown targets from the measured scattered field is challenging due to the intrinsic nonlinearity and ill-posedness. In this article, a new scheme, named the modified contrast scheme (MCS), is proposed to tackle nonlinear inverse scattering problems (ISPs). A local-wave amplifier coefficient is used to form the modified contrast, which is able to alleviate the global nonlinearity in original ISPs without decreasing the accuracy of the problem formulation. Moreover, the modified contrast is more suitable to be the input of the deep learning scheme, due to the unity bound of the modified contrast. The numerical results show that MCS with the modified contrast input performs well in both 2-D and 3-D testing examples in real time after offline training process, even in high-relative-permittivity cases. Compared with the dominant current scheme, a significant improvement is achieved in reconstructing high-contrast scatterers.
39. Wearable Magnetoinductive Waveguide for Low-Loss Wireless Body Area Networks
用于低损耗无线体域网的可穿戴磁感应波导
Vigyanshu Mishra. Asimina Kiourti.
原文链接
“A novel approach of wearable magnetoinductive waveguide (MIW) is introduced for wireless body area network (WBAN) communications that brings forward significant advances over state-of-the-art. The MIW consists of series of electrically small resonant loops worn upon the human body to support magnetoinductive waves (MI waves) for low-loss/low-power WBANs. Compared to previous approaches, the proposed MIW exhibits 63 dB lower loss, translating conventional power levels of mW down to or nW. In this work, we introduce the operating principle of MIW WBAN through underlying theory and dispersion diagrams. The proof-of-concept numerical and experimental results are reported for frequency bands centered around 40.4 and 80.7 MHz for a cylindrical human limb and are found to be in excellent agreement. Design guidelines are extensively discussed to accommodate several possible scenarios (frequency selection, gap between the loops, number of loops, and loop radius) along with practical considerations including loop tilts, anatomical limbs, limb movements, unequal loop gaps, and loop failure. Specific absorption rate (SAR) calculations confirm that this technology is highly safe for human use. A bit error rate (BER) analysis further demonstrates that the MIW can form a high-quality communication channel for WBAN. Overall, the reported approach unveils a new possibility of low-loss and seamless WBANs.
40. Radar Cross Section of Chipless RFID Tags and BER Performance
无芯片 RFID 标签的雷达截面和 BER 性能
Michele Borgese. Simone Genovesi. Giuliano Manara. Filippo Costa.
原文链接
“The performance of different chipless RFID tag topologies is analyzed in terms of radar cross section (RCS) and bit error rate (BER). It is shown that the BER is mainly determined by the tag RCS once a standard reading scenario is considered and a fixed size of the tag is chosen. It is shown that the arrangement of the resonators in the chipless tag plays a crucial role in determining the cross-polar RCS of the tag. The RCS of the tag is computed theoretically by using array theory where each resonator is treated as a separate scatterer completely characterized by a specific reflection coefficient. Several resonators arrangements (periodic and nonperiodic) are compared, keeping the physical area of the tag fixed. Theoretical and experimental analyses demonstrate that the periodic configuration guarantees the maximum achievable RCS, thus providing a global lower BER of the chipless RFID communication system. We believe that the BER is the more meaningful and fair figure of merit (FoM) for comparing the performance of different tags than bit/cm 2 or bit/Hz since the increase in encoded information of the tag is useful only if it can be correctly decoded.
41. A Novel Cesaro Fractal EBG-Based Sensing Platform for Dielectric Characterization of Liquids
基于 Cesaro 分形 EBG 的新型液体介电表征传感平台
Ali Arif. Amna Zubair. Kashif Riaz. Muhammad Qasim Mehmood. Muhammad Zubair.
原文链接
“This article presents a compact, cost-effective, and contactless fractal modified electromagnetic bandgap structure (EBG)-based microwave sensing platform for dielectric characterization of liquids by analyzing the variation in the reflection coefficient of an antenna. The reported design is composed of a triangular-shaped antenna ( ) placed over a array of Cesaro fractal-based EBG plane ( ) operating at 2.45 GHz. A significant enhancement of the -field in the sensing region has been achieved with the incorporation of Cesaro fractals in the EBG plane which results in increased sensitivity and compactness. To validate its performance, absolute solutions of butan-1-ol, methanol, and water are loaded, and a maximum measured sensitivity of 0.875% and a maximum quality factor of 90.05 are achieved. Moreover, a maximum rms error in retrieved values of dielectric constant and loss tangent of liquid under test is found to be 1.092% and 0.813%, respectively. Our demonstrated EBG-based sensor has a compact footprint with good precision, affordability, and ease of operation in detecting liquids for microwave sensing applications.
42. Chipless RFID Reading Method Insensitive to Tag Orientation
对标签方向不敏感的无芯片 RFID 读取方法
Nicolas Barbot. Olivier Rance. Etienne Perret.
原文链接
“This article presents a new reading method which is able to decode the backscattered signal of a chipless tag without any assumption on its orientation. The method is analytically justified by a model and can be applied to any known scatterers or chipless tags composed of multiple resonators. The presented approach is based on two orthogonal measurements in co-polarization on the reader part and can be optionally combined with time gating. Finally, read range is not reduced with this method since the entire energy of the chipless tag’s antenna mode is exploited by the reader.
43. A Hierarchical Bayesian Inversion Method for Electromagnetic Imaging of Inhomogeneous Objects With Piecewise Homogeneities
具有分段均匀性的非均匀物体电磁成像的分层贝叶斯反演方法
Fang-Fang Wang. Qing Huo Liu.
原文链接
“Electromagnetic imaging of inhomogeneous objects is a nonlinear inverse scattering problem which can be effectively handled by means of linear inversion methods or nonlinear optimization methods. In addition to being nonlinear, inverse scattering problems are also ill-posed which can be overcome through a regularization scheme by taking into account some kind of
priori information. However, it is not straightforward to incorporate such inhomogeneity prior information into conventional inversion methods. In this work, we propose an innovative method to solve the problem of imaging inhomogeneous objects with piecewise homogeneity. Under Born approximation (BA), this problem is cast into a linear inversion one which is then addressed by means of a hierarchical Bayesian inversion method. To account for the piecewise homogeneity of the image, a Gaussian mixture model (GMM) is developed to enforce the feature. Specifically, a hidden label variable which is associated with each pixel is introduced for the class of materials and the contrast of each pixel is modeled as a mixture of independent Gaussian priors. Then, the proposed hierarchical Bayesian inversion method incorporates the GMM to the variational Bayesian inference framework to approximate the posterior distribution of all the unknowns (the unknown contrast, hidden label variable, and other model parameters). In addition, the damped generalized approximate message passing (GAMP) is utilized to circumvent the matrix inversion, making the overall process very computationally efficient. Extensive numerical examples will be shown to demonstrate the effectiveness of the proposed method.
44. Microwave Wireless Powering of Sensored Agricultural Tile Drainages
感应农业瓷砖排水的微波无线供电
Abbas Semnani. Badri Baskaran. Dimitrios Peroulis.
原文链接
“In this article, a new technique for wireless powering of agricultural sensors buried deep underground is introduced and experimentally investigated. In this technique, the agricultural drainage tiles are utilized as waveguides to carry electromagnetic (EM) energy over long distances. By using high-efficiency rectifiers, the propagating EM waves are then converted into dc power to charge the batteries of underground sensors. A prototype 1 GHz rectenna system is fabricated and implemented on an 8 in tile to prove this concept experimentally. Various measurements are conducted for both the rectenna and the entire tile system, including realistic scenarios such as partially covered tiles and tile in the presence of water. Considering the emerging digital agriculture, the proposed technique will open the potential for detailed underground geochemistry studies, which will allow us to better monitor the transport of liquids and gases through millions of miles of agricultural tile drainage networks.
45. Fast Simulation of Electromagnetic Fields in Doubly Periodic Structures With a Deep Fully Convolutional Network
用深全卷积网络快速模拟双周期结构中的电磁场
Yiqian Mao. Qiwei Zhan. Runren Zhang. Dezhi Wang. Wei-Feng Huang. Qing Huo Liu.
原文链接
“The simulation of electromagnetic fields in many applications with double periodicity can be viewed as an image-to-image translation problem, where the structure is known and the fields need to be predicted. In this work, we take extreme ultraviolet (EUV) lithography as an example and propose a very efficient technique based on the U-Net architecture, a deep fully convolutional network (FCN). The U-Net is trained with data of some typical patterns in a 128 nm nm unit cell, and good accuracy can be obtained in the prediction of the near field on much larger unit cells with complex patterns. Furthermore, numerical experiments demonstrate that the proposed method is three orders of magnitude faster than conventional state-of-the-art methods, such as the spectral-element spectral-integral method.
46. DOA and Range Estimation Using a Uniform Linear Antenna Array Without A Priori Knowledge of the Source Number
使用均匀线性天线阵列进行 DOA 和距离估计，无需源编号的先验知识
Jianzhong Li. Yide Wang. Zhigang Ren. XiaoBo Gu. Ming Yin. Zongze Wu.
原文链接
“summary
47. A 28 GHz and 60 GHz Dual-Band On-Chip Antenna for 5G-Compatible IoT-Served Sensors in Standard CMOS Process
28 GHz 和 60 GHz 双频段片上天线，适用于标准 CMOS 工艺的 5G 兼容物联网服务传感器
Pascal Burasa. Tarek Djerafi. Ke Wu.
原文链接
“summary
48. Four-Port Wideband Annular-Ring Patch Antenna Generating Four Decoupled Waves for 5G Multi-Input–Multi-Output Access Points
四端口宽带环形贴片天线为 5G 多输入多输出接入点生成四个解耦波
Kin-Lu Wong. Jian-Zhong Chen. Wei-Yu Li.
原文链接
“summary
49. Fast Antenna Characterization Improvement by Pattern Rotation
通过方向图旋转快速改进天线特性
Nicolas Mézières. Benjamin Fuchs. Laurent Le Coq. Jean-Marie Lerat. Romain Contreres. Gwenn Le Fur.
原文链接
“summary
50. Programmable Metasurface Based on Substrate-Integrated Waveguide for Compact Dynamic-Pattern Antenna
基于基板集成波导的用于紧凑型动态模式天线的可编程超表面
Shangyang Li. Feng Xu. Xiang Wan. Tie Jun Cui. Ya-Qiu Jin.
原文链接
“summary
51. A Wideband Circular-Polarized Beam Steering Dielectric Resonator Antenna Using Gravitational Ball Lens
一种使用重力球透镜的宽带圆偏振波束控制介质谐振天线
Zhijiao Chen. Qi Liu. Benito Sanz-Izquierdo. Haiwen Liu. Junsheng Yu. Xiaodong Chen.
原文链接
“This communication proposes a wideband circular-polarized (CP) beam steering dielectric resonator antenna (DRA) using a gravitational ball lens. It offers a passive means for wall or ceiling mounted base station antennas to adjust their patterns by the gravity of ball lenses. This novel antenna concept overcomes the difficulties of achieving wideband axial ratio versus the pattern reconfigurability of the existing antennas. The operation of the ball lens has been intensively studied. It is found that the ball lens provides 1.2 dB antenna gain enhancement, whereas enabling beam tilting via energy coupling to the offset direction. As a demonstration, a codesign of DRA and ball lens has been developed at 2.4 GHz, achieving 42% impedance bandwidth, 39% axial ratio bandwidth, and ±40° beam steering. Reasonable agreement between simulated and measured results is observed. The proposed DRA provides a low-cost solution for base stations to be mounted at an angle and effectively cover the indoor users.
52. Compact Microstrip Antennas With Enhanced Bandwidth for the Implanted and External Subsystems of a Wireless Retinal Prosthesi
具有增强带宽的紧凑型微带天线，用于无线视网膜假体的植入和外部子系统
Siroos Bahrami. Gholamhosein Moloudian. Seyyed Reza Miri-Rostami. Toni Björninen.
原文链接
“summary
53. Compact 2 × 2 MIMO Antenna With Low Mutual Coupling Based on Half Mode Substrate Integrated Waveguide
基于半模基板集成波导的具有低互耦的紧凑型 2 × 2 MIMO 天线
Abubaker Ahmed Elobied. Xue-Xia Yang. Tian Lou. Steven Gao.
原文链接
“summary
54. A Compact Phase-Controlled Pattern-Reconfigurable Dielectric Resonator Antenna for Passive Wide-Angle Beam Scanning
一种用于无源广角波束扫描的紧凑型相控模式可重构介质谐振器天线
Zhijiao Chen. Zeyu Song. Haiwen Liu. Xiaoming Liu. Junsheng Yu. Xiaodong Chen.
原文链接
“summary
55. Backward-to-Forward Wide-Angle Fast Beam-Scanning Leaky-Wave Antenna With Consistent Gain
具有一致增益的后向前向广角快速波束扫描漏波天线
Hao Jiang. Kuiwen Xu. Qingfeng Zhang. Yang Yang. Debabrata K. Karmokar. Shichang Chen. Peng Zhao. Gaofeng Wang. Liang Peng.
原文链接
“summary
56. Surrogate-Assisted Quasi-Newton Enhanced Global Optimization of Antennas Based on a Heuristic Hypersphere Sampling
基于启发式超球面采样的代理辅助拟牛顿增强天线全局优化
Zhen Zhang. Hong Cai Chen. Qingsha S. Cheng.
原文链接
“This communication presents a novel surrogate-assisted quasi-Newton enhanced global optimization (SA-QNEGO) algorithm. In this proposed method, the heuristic hypersphere sampling (HHS) method is used to obtain representative samples. The surrogate model is built based on the low-fidelity model. The quasi-Newton enhanced differential evolution (DE) method is designed to optimize the surrogate model. Finally, the optimal design of a high-fidelity model is obtained through a space mapping procedure. The proposed algorithm is verified through two antenna design examples including a dipole antenna with balun and an SIW cavity-backed slot antenna. The results show that the proposed algorithm finds a more accurate minimum value with less computational time than direct optimization using DE.
57. High Isolation and Low Cross-Polarization of Low-Profile Dual-Polarized Antennas via Metasurface Mode Optimization
通过超表面模式优化实现低剖面双极化天线的高隔离度和低交叉极化
Sihao Liu. Deqiang Yang. Yongpin Chen. Xiaokun Zhang. Yong Xiang.
原文链接
“summary
58. Difference Pattern Synthesis Based on Superposition Principle
基于叠加原理的差分模式合成
Yang-Xiao Qi. Jian-Ying Li.
原文链接
“summary
59. Synthesis of Sparse Near-Field Focusing Antenna Arrays With Accurate Control of Focal Distance by Reweighted l1 Norm Optimization
通过重加权l1范数优化精确控制焦距的稀疏近场聚焦天线阵列的合成
Zi Xuan Huang. Yu Jian Cheng. Hai Ning Yang.
原文链接
“summary
60. High-Gain Phased Array Antenna With Endfire Radiation for 26 GHz Wide-Beam-Scanning Applications
具有端射辐射的高增益相控阵天线，适用于 26 GHz 宽波束扫描应用
Chunxu Mao. Mohsen Khalily. Pei Xiao. Long Zhang. Rahim Tafazolli.
原文链接
“summary
61. Miniaturized Wideband Planar Antenna Using Interembedded Metasurface Structure
使用嵌入式超表面结构的小型化宽带平面天线
Dongxu Chen. Wanchen Yang. Quan Xue. Wenquan Che.
原文链接
“summary
62. Design of Sum and Difference Patterns by Optimizing Element Rotations and Positions for Linear Dipole Array
通过优化线性偶极子阵列的元件旋转和位置来设计和和差模式
Ming Li. Yanhui Liu. Y. Jay Guo.
原文链接
“summary
63. Reducing Volume Integrals to Line Integrals for Some Functions Associated With Schaubert–Wilton–Glisson Basis Function
将一些与 Schaubert-Wilton-Glisson 基函数相关的函数的体积积分化简为线积分
Rayleigh R. Chang. Kun Chen. Jiangong Wei. Mei Song Tong.
原文链接
“summary
64. Acceleration of the Computation of the Method of Moments EFIE Impedance Matrix From an Updated Fraunhofer Criterion
从更新的弗劳恩霍夫准则加速矩量法 EFIE 阻抗矩阵的计算
Christophe Bourlier.
原文链接
“summary
65. Dual-Band Polarization Conversion Metasurface for RCS Reduction
用于 RCS 减少的双波段偏振转换超表面
Changfeng Fu. Lianfu Han. Chao Liu. Zhijie Sun. Xili Lu.
原文链接
“summary
66. Broadband Anomalous Refractor Based on Dispersion Engineering of Spoof Surface Plasmon Polaritons
基于欺骗表面等离子体激元色散工程的宽带反常折射体
Jie Yang. Jiafu Wang. Xuezhi Zheng. Anxue Zhang. Raj Mittra. Guy A. E. Vandenbosch.
原文链接
“summary