PIER M | PIER Journals

2024-10-17

PIER M

Vol. 129, 131-139, 2024

download: 74

A Novel Subarray Partitioning Algorithm for Small Sparse Transmitting Arrays in Microwave Power Transmission

Yuecheng Cui and Jianxiong Li

To enhance the performance of microwave power transmission (MPT) systems' transmitting arrays, it is essential to comprehensively consider key factors such as beam collection efficiency (BCE), the level of sidelobes outside the reception area (CSL), and expense. Current transmitting array models commonly suffer from issues like low BCE, a large number of array elements, and complex feeding systems. Addressing these issues, this paper proposes a novel transmitting array design referred to as Large Spacing Nonuniform-Excitation Sparse Planar Array (LSNSPA) and introduces a new subarray partitioning algorithm named Multi-Parameter Dynamic Weight Particle Swarm Optimization for Rectangular Subarrays (MP-DWPSO-RS). The algorithm is capable of optimizing the subarray structure, as well as the element positions and excitations, during each iteration. This paper achieves a relatively higher BCE metric than other arrays by utilizing only a small number of sub-arrays, through the combination of a large-spacing distribution strategy and a sub-array partitioning strategy. Simulations have verified that the proposed MP-DWPSO-RS algorithm can achieve a BCE of nearly 94% when optimizing the LSNSPA with an aperture of 4.5λ × 4.5λ consisting of 8 × 8 elements.

A Novel Subarray Partitioning Algorithm for Small Sparse Transmitting Arrays in Microwave Power Transmission

2024-10-17

PIER M

Vol. 129, 119-129, 2024

doi:10.2528/PIERM24082006

download: 98

A Compact Super-Wideband MIMO Antenna for Wireless Communication Systems

Rania R. Elsharkawy

This paper presents a super-wideband antenna for operation in X, Ku, K, Ka, V, and W band applications. A monopole antenna with a semi-circular shape, fed through a transmission line and a Co-Planar Waveguide (CPW), is presented. It has a bandwidth ranging from 11.5 GHz to more than 100 GHz. A Multiple-Input Multiple-Output (MIMO) system with quad elements is constructed from the proposed antenna. The MIMO elements are arranged in an orthogonal ar-rangement to decrease the coupling between them. The MIMO system performance is investigated. The antenna is fabricated and measured, and it has a maximum gain of 8.37 dBi. The maximum radiation efficiency of the proposed antenna reaches 95% over most of the band. For the MIMO system, the maximum Envelope Correlation Coefficient (ECC) is 0.06, and the Diversity Gain (DG) is 9.7 dB.

A Compact Super-wideband MIMO Antenna for Wireless Communication Systems

2024-10-14

PIER M

Vol. 129, 111-117, 2024

doi:10.2528/PIERM24091103

download: 104

Combining of Phase Cancellation and Absorption for Broadband High RCS Reduction Metasurface Design

Honggang Hao , Yi Shen , Wen Huang , Siyao Li and Zonggui Li

To enhance the reduction of radar cross section (RCS) and improve stealth performance, a phase cancellation and absorbing metasurface(PCAM)is designed in this paper. The PCAM is composed of a chessboard layout of circular units and square units, and it not only converts absorbed incident electromagnetic waves into heat to reduce the intensity of reflected electromagnetic waves, but also simultaneously controls the phase of the reflected electromagnetic waves, achieving phase cancellation. This enables the metasurface to be exhibited with ultralow backscatter. After simulation verification, the metasurface can achieve RCS reduction of over 15 dB in the 4.3-11 GHz range for vertical incidence, with a fractional bandwidth of approximately 87.6%, and over 15 dB in the 5.4-11.2 GHz range for a 30° oblique incidence, demonstrating good stability for oblique angles. The metasurface has increased the reduction level from over 10 dB to over 15 dB, significantly enhancing the RCS reduction. Additionally, in the co-planar state with a central curvature of 90°, it can also achieve RCS reduction of over 10 dB in the 3.2-9.9 GHz range, showing significant potential for practical applications.

Combining of Phase Cancellation and Absorption for Broadband High RCS Reduction Metasurface Design

2024-10-13

PIER M

Vol. 129, 105-110, 2024

doi:10.2528/PIERM24090801

download: 81

A Miniaturized Antipodal Vivaldi Antenna for High-Power Design in X-Band

Liangliang Zhao , Aidong Li , Chuwei Li , Yongmao Wang , Mingxuan Zheng , Dengyang Song , Chenlu Liu , Yongtao Liang , Huiling Zhao , Chufeng Hu and Tao Ma

A compact antipodal Vivaldi antenna (AVA) integrated with circularly shaped loads and some elliptic slits etched in tapered slots is proposed in this paper. First, the elliptic slits etched in two tapered slots are employed for wideband application in X-band. Then, the value of max power capacity increasing from 0.47 MW to 0.82 MW is mainly due to two circularly shaped loads. Moreover, the size of the antenna is decreased to 0.44λ_middle × 0.42λ_middle. The configuration is measured to confirm the simulated results. Based on these, a novel antipodal Vivaldi antenna with compact size is successfully designed and applied in high-power field at X-band.

A Miniaturized Antipodal Vivaldi Antenna for High-power Design in X-band

2024-10-13

PIER M

Vol. 129, 99-104, 2024

doi:10.2528/PIERM24081003

download: 77

Adaptive Block-Based Krylov Subspace Basis Functions for Solving Bistatic Scattering Problems

Haoran Yuan , Zhonggen Wang , Yufa Sun and Wenyan Nie

This study aims to improve the efficiency of constructing basis functions for solving the electromagnetic scattering problem of objects using the method of moments combined with compressive sensing and Krylov subspace. To this end, a region decomposition method based on a clustering algorithm is proposed to accelerate the construction process of Krylov subspace basis functions. First, the midpoints of the common edges of triangular pairs are used to form a clustered dataset. Then, the initial clustering center is set, and the processes of clustering center updating and regional decomposition of the constructed dataset are completed iteratively. Finally, each subdomain is expanded according to the average distance from data points to the clustering center to ensure the continuity of currents. The numerical computation results show that the proposed method can achieve significant time efficiency.

Adaptive Block-based Krylov Subspace Basis Functions for Solving Bistatic Scattering Problems

2024-10-12

PIER M

Vol. 129, 91-97, 2024

doi:10.2528/PIERM24072506

download: 78

Convergence Determination Method for Uncertainty Analysis Surrogate Models Based on MEAM

Bing Hu , Yujia Song , Pengxiang Wang , Shining Lin and Jinjun Bai

In recent years, uncertainty analysis has become a hot topic in the field of Electromagnetic Compatibility (EMC), and non-intrusive uncertainty analysis methods have been widely applied due to their advantage of obtaining results without modifying the original solver. Among them, the Surrogate Model Method has attracted widespread attention from researchers in the field of EMC due to its high computational efficiency and resistance to the curse of dimensionality. However, the issue of determining the convergence of the surrogate models seriously affects the computational efficiency and convenience of this method in practical applications. To address this issue, a convergence determination method for uncertainty analysis surrogate models based on Mean Equivalent Area Method (MEAM) is proposed in this paper. The complete convergence time of the Surrogate Model Method can be accurately determined through iterative calculation by this method, and the effectiveness of the proposed method is verified by calculating parallel cable crosstalk prediction examples from published literature. Finally, based on the proposed convergence determination method, the real-time convergence determination problem of the Surrogate Model Method is also preliminarily discussed in this paper, and by establishing a polynomial relationship, the real-time convergence of the Surrogate Model Method can be roughly determined.

Convergence Determination Method for Uncertainty Analysis Surrogate Models Based on MEAM

2024-10-12

PIER M

Vol. 129, 83-90, 2024

doi:10.2528/PIERM24083102

download: 87

Array Pattern Synthesis Using a New Adaptive Trapezoid Window Function for Sidelobe Suppression and Nulls Control

Jafar Ramadhan Mohammed

Conventional sidelobe reduction methods such as analytical or parametric approaches and complex numerical optimization approaches were accomplished via specific tapering windows. Among all of the tapering windows, a rectangular window gives simplest array feeding network, narrower beam width, and highest directivity. The only drawback is its highest sidelobe level due to sharp edges at the array ends. In this paper, a simple trapezoid taper window, which is something between typical rectangular and triangular windows, is first suggested as a best compromise between uniform and non-uniform amplitude window functions. Then, it is further developed by making it adaptive or adjustable by including a number of controllable-amplitude elements in the linear edges of the trapezoid window. Thus, the proposed taper window becomes very flexible to accommodate different user-defined constraints. To find the optimal values of those controllable-amplitude elements, a genetic optimization algorithm is used to design and optimize the trapezoid window such that a desired sidelobe peaks and controlled nulls can be met while maximizing the complexity reduction as much as possible. The linear and planar antenna arrays are simulated to validate the superiority of the proposed taper window.

Array Pattern Synthesis Using a New Adaptive Trapezoid Window Function for Sidelobe Suppression and Nulls Control

2024-10-09

PIER M

Vol. 129, 75-82, 2024

doi:10.2528/PIERM24081305

download: 115

A Spaceborne Inverse Sliding Spotlight SAR for Nonuniform Scanned Scene

Yangyang Chen , Wei Xu , Pingping Huang , Weixian Tan and Yaolong Qi

Inverse sliding spotlight synthetic aperture radar (SAR) is not as high as sliding spotlight SAR in azimuth resolution. Its azimuth resolution is constant, and it cannot meet the needs of multiple different azimuth resolutions. In order to solve this problem, a spaceborne inverse sliding spotlight SAR for nonuniform scanned scene is proposed. The design of the proposed inverse sliding spotlight SAR includes two parts: the design of the adaptive azimuth beam steering law and the design of the imaging algorithm. In the first part, the design of the adaptive azimuth beam steering law is based on multiple specific azimuth resolution requirements and the parameters of scanned scene. In the second part, the design of the imaging algorithm for the proposed inverse sliding spotlight SAR consists of three steps: filtering processing, phase compensation and upsampling processing, and image formation. Compared with the conventional inverse sliding spotlight SAR, the proposed inverse sliding spotlight SAR can achieve different azimuth resolution requirements for scanning targets at different positions in the scanned scene. Finally, the correctness of the proposed inverse sliding spotlight SAR is verified by simulation experiment and UAV SAR experiment.

A Spaceborne Inverse Sliding Spotlight SAR for Nonuniform Scanned Scene

2024-10-05

PIER M

Vol. 129, 65-73, 2024

doi:10.2528/PIERM24062502

download: 131

Human Identification Using Near-Field BI-Static Radar at Low Frequencies

Nicole Tan Xin Hui , Ng Oon-Ee , Gobi Vetharatnam , Teoh Chin Soon and Grant Ellis

Near-field scattering of human targets in the view of a bi-static, radar-like sensor operating in the lower radiofrequencies is used as an alternative to traditional biometric identification systems. These radiofrequency-based human sensor systems have emerged as a promising solution to address privacy concerns, particularly those associated with audio and visual data that extract sensitive personally identifiable information. In this paper, we propose a novel method for privacy-preserving human identification using bi-static radar-like sensors. Unlike conventional radar systems that rely on echoes and reflections in the far field, our approach is based on the transmission of signals through and around users as they pass through a transmitter and receiver. Instead of the more commonly used linear or segmented swept frequencies, this work utilizes discrete swept frequencies to transmit and receive radiofrequency signals. We have examined the performance of seven machine learning models in terms of accuracy and processing time and found that the Extra Trees ensemble model produced the best results, with an accuracy rate of 94.25\% for a sample size of 31 individuals using an Intel(R) Core(TM) i5-10300H CPU @ 2.50 GHz processor.

Human Identification Using Near-field Bi-static Radar at Low Frequencies

2024-09-30

PIER M

Vol. 129, 53-64, 2024

doi:10.2528/PIERM24080803

download: 163

Study of an Electric Vehicle WPT System with Ring-Series Passive Magnetic Shielding Based on Dual Transmitting Coils

Xueyi Zhang , Zhibang Luo , Sai Zhang , Bin Li , Ziyue Gan and Zhongqi Li

In the design of wireless power transfer (WPT) systems for electric vehicles, minimizing magnetic leakage while maintaining high transmission efficiency is a challenging problem. To this end, a novel structure featuring dual transmitting coils and a ring-series magnetic shielding coil (RMSDT) is proposed to reduce magnetic leakage during system charging, thereby enhancing system safety performance. Additionally, the Particle Swarm Optimization (PSO) algorithm is employed to optimize system parameters, aiming to achieve high transmission efficiency while maintaining low magnetic leakage. To validate the effectiveness of the proposed design, a shielded WPT system for electric vehicles has been developed. Its performance is verified through a combination of experiments and simulations. The results demonstrate that the PSO algorithm significantly enhances transmission efficiency compared to traditional optimization methods. At an output power of 3.7 kW, the peak transmission efficiency exceeds 95%, representing an improvement of 4.63% compared to the conventional for-loop algorithm. Furthermore, the leakage magnetic field of the RMSDT structure in the target region is only 16.08 μT, which is effectively reduced by 41.8% compared to the conventional WPT structure and sacrifices only 0.21% transmission efficiency. In summary, this paper can provide some references to the safety and efficiency of electric vehicle WPT.

Study of an Electric Vehicle WPT System with Ring-series Passive Magnetic Shielding Based on Dual Transmitting Coils

2024-09-26

PIER M

Vol. 129, 43-52, 2024

doi:10.2528/PIERM24061204

download: 225

YOLOv8 -DEC: Enhancing Brain Tumor Object Detection Accuracy in Magnetic Resonance Imaging

Zekun Lin , Weiming Lin and Fuchun Jiang

Brain tumors are characterized by the fast growth of aberrant brain cells, which poses a considerable risk to an adult's health since it can result in severe organ malfunction or even death. Magnetic resonance imaging (MRI) provides vital information for comprehending the nature of brain tumors, directing treatment approaches, and enhancing diagnostic precision. It displays the diversity and heterogeneity of brain tumors in terms of size, texture, and location. However, manually identifying brain tumors is a difficult and time-consuming process that could result in errors. It is proposed that an enhanced You Only Look Once version 8 (YOLOv8) model aids in mitigating the drawbacks associated with manual tumor detection, with the objective of enhancing the accuracy of brain tumor detection. The model employs the C2f_DySnakeConv module to improve the perception and discrimination of tumors. Additionally, it integrates Content-Aware ReAssembly of FEatures (CARAFE) to efficiently expand the network's receptive area to integrate more global contextual information, and Efficient Multi-Scale Attention (EMA) to improve the network's sensitivity and resolution for lesion features. According to the experimental results, the improved model performs better for brain tumor detection than both the open-source model and the original YOLOv8 model. It also achieves higher detection accuracy on the brain tumor image dataset than the original YOLOv8 model in terms of precision, recall, mAP@0.5, and mAP@0.5~0.95 above, respectively, of 2.71%, 2.34%, 2.24%, and 3.73%.

YOLOv8-DEC: Enhancing Brain Tumor Object Detection Accuracy in Magnetic Resonance Imaging

2024-09-24

PIER M

Vol. 129, 33-41, 2024

doi:10.2528/PIERM24080201

download: 220

A Compact Four Port MIMO Antenna for n261 Millimeter Wave Band Applications

Reena Aggarwal , Ajay Roy and Rajeev Kumar

This article introduces a compact design for a four-element MIMO antenna for millimeter-wave (mmWave) communications for specifically n261 band having range from 27.5 GHz to 28.35 GHz with a bandwidth of 850 MHz. The single antenna structure uses a rectangular patch having four diamond-shaped slots in the feed-plane. On the ground plane, a dumbbell-shaped slot is positioned below the rectangular patch. A Rogers RT/Duroid 5880 substrate with ultra-thin thickness is used in this design. The optimized design for four-port MIMO antenna has small size with dimensions of 20 mm × 19 mm × 0.254 mm. The MIMO parameters such ECC is less than 0.011, and DG is greater than 9.90 dB in the mentioned band, which are within tolerance limits. The isolation between neighbouring MIMO elements is also less than -19.5 dB.

A Compact Four Port MIMO Antenna for n261 Millimeter Wave Band Applications

2024-09-22

PIER M

Vol. 129, 23-32, 2024

doi:10.2528/PIERM24080403

download: 273

Spoof Surface Plasmon Polaritons-Based Feeder for a Dielectric Rod Antenna at Microwave Frequencies

Rishitej Chaparla , Shaik Imamvali , Sreenivasulu Tupakula , Krishna Prakash , Shonak Bansal , Mohd Muzafar Ismail and Ahmed Jamal Abdullah Al-Gburi

This work explores the potential of spoof surface plasmon polaritons (SSPPs) for effectively feeding high-frequency antennas operating in the extremely high-frequency (EHF) range. An innovative approach is introduced in this study to utilize SSPP to feed a dielectric rod antenna. The design incorporates a straightforward dielectric rod antenna fabricated using FR-4 material with a relative permittivity of 4.3. Compared to conventional tapered dielectric rod antennas and their corresponding feeding configurations, this design presents the potential benefit of achieving an improved gain of up to 16.85 dBi using a specific antenna length of 7.6λ₀. Through careful design optimization, we achieved impedance matching and directional radiation characteristics at a frequency of 7.3 GHz. To validate our design and assess its performance, we conducted simulations using the CST Microwave Studio. This study aims to demonstrate the effectiveness and practicality of the proposed dielectric rod antenna with an SSPP feed.

Spoof Surface Plasmon Polaritons-based Feeder for a Dielectric Rod Antenna at Microwave Frequencies

2024-09-13

PIER M

Vol. 129, 11-22, 2024

doi:10.2528/PIERM24071705

download: 239

A Dual Transmission Zero Bandpass Filter Employing Novel Hairpin-Coupled Resonators for Improved Stopband Characteristics Application the Vital Signs Detection Radar

Mingming Gao , Yunshu Yang , Jingchang Nan , Handong Wu , Xiaolin Wang and Xuanye Cui

Conventional hairpin band-pass filters (BPFs) typically have poor stopband performances. Therefore, this paper proposes a BPF with a center frequency of 24 GHz that employs a novel hairpin-coupled structure. An enhanced hairpin-coupled resonator topology is also introduced to improve the stopband suppression characteristics. Specifically, the proposed resonator and filter are configured through a hairpin structure and source-third resonator coupling, which afford a miniaturized size and coupling of the transmission zeros. Then, an equivalent circuit model is simulated to conduct loss analysis of the millimeter-wave (mm-wave) BPF, and the corresponding analytical parameters and result data are extracted. Furthermore, fast synthesis is achieved for the high stopband suppression mm-wave filter. The compact BPF developed is fabricated using the quart glass process, with the corresponding measurements revealing that the insertion Loss (IL) is less than 4.5 dB, and the return loss (RL) exceeds 9 dB within the passband. Meanwhile, the stopband suppression at 20.6 GHz and 28.6 GHz can reach 43 dB and 35 dB, respectively. Those advanced performances demonstrate the promising prospect of the proposed filter for its application in biological radar life feature monitoring.

A Dual Transmission Zero Bandpass Filter Employing Novel Hairpin-coupled Resonators for Improved Stopband Characteristics Application the Vital Signs Detection Radar

2024-09-12

PIER M

Vol. 129, 1-10, 2024

doi:10.2528/PIERM24072405

download: 281

A Compact High-Isolation Tri-Band MIMO Antenna Based on Characteristic Mode Analysis

Jinrong Su , Shiqi Di , Chunhui Yao and Xinwei Chen

This paper presents a compact 3-port multiple-input multiple-output (MIMO) antenna for 5G wireless communication, covering the 2.6 GHz, 3.5 GHz, and 4.8 GHz bands. Three orthogonal modes (TMsub>10, TMsub>01, and TMsub>20 modes) are excited to realize tri-band operation and high isolation simultaneously. Using characteristic mode analysis (CMA), dual-slot structures and I-shaped patches are introduced to block coupling path, and the isolation is improved. Simulated and measured results show that the proposed antenna operates in the frequency bands of 2.57 to 2.64 GHz, 3.4 to 3.5 GHz, and 4.8 to 4.9 GHz with isolation better than 20.6 dB. In addition, it can be calculated that Envelope Correlation Coefficient (ECC) (<0.06), Diversity Gain (DG) (>9.99 dB), Total Active Reflection Coefficient (TARC) (<-10 dB), and Channel Capacity Loss (CCL) (<0.45 bits/Hz/sec) are in acceptable level, implying excellent diversity performance and data transmission quality. It is worth noting that the evolution of the antenna is entirely based on the CMA, which greatly simplifies the design process. The antenna has the advantages of high isolation, compact structure, easy processing, and low cost, positioning it as a compelling candidate for integration into 5G wireless communication systems.