IEEE journal of microwaves最新文献

{"title":"Human Activity Recognition Based on Feature Fusion of Millimeter Wave Radar and Inertial Navigation","authors":"Jiajia Shi;Yihan Zhu;Jiaqing He;Zhihuo Xu;Liu Chu;Robin Braun;Quan Shi","doi":"10.1109/JMW.2025.3539957","DOIUrl":"https://doi.org/10.1109/JMW.2025.3539957","url":null,"abstract":"Human activity recognition (HAR) technology is increasingly utilized in domains such as security surveillance, nursing home monitoring, and health assessment. The integration of multi-sensor data improves recognition efficiency and the precision of behavioral analysis by offering a more comprehensive view of human activities. However, challenges arise due to the diversity of data types, dimensions, sampling rates, and environmental disturbances, which complicate feature extraction and data fusion. To address these challenges, we propose a HAR approach that fuses millimeter-wave radar and inertial navigation data using bimodal neural networks. We first design a comprehensive data acquisition framework that integrates both radar and inertial navigation systems, with a focus on ensuring time synchronization. The radar data undergoes range compression, moving target indication (MTI), short-time Fourier transforms (STFT), and wavelet transforms to reduce noise and improve quality and stability. The inertial navigation data is refined through moving average filtering and hysteresis compensation to enhance accuracy and reduce latency. Next, we introduce the Radar-Inertial Navigation Multi-modal Fusion Attention (T-C-RIMFA) model. In this model, a Convolutional Neural Network (CNN) processes the 1D inertial navigation data for feature extraction, while a channel attention mechanism prioritizes features from different convolutional kernels. Simultaneously, a Vision Transformer (ViT) interprets features from radar-derived micro-Doppler images. Experimental results demonstrate significant improvements in HAR tasks, achieving an accuracy of 0.988. This approach effectively leverages the strengths of both sensors, enhancing the accuracy and robustness of HAR systems.","PeriodicalId":93296,"journal":{"name":"IEEE journal of microwaves","volume":"5 2","pages":"409-424"},"PeriodicalIF":6.9,"publicationDate":"2025-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10916995","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143654924","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Analysis of Transmission-Line-Based Quasi-All-Pass Network for Phase-Shifter Design","authors":"Shih-Shen Fan;Tsu-Te Huang;Jia-Shiang Fu","doi":"10.1109/JMW.2025.3540560","DOIUrl":"https://doi.org/10.1109/JMW.2025.3540560","url":null,"abstract":"All-passnetworks (APNs) have long been used in the design of phase shifters. A transmission-line-based quasi-all-pass network (TL-based QAPN) is a series-<inline-formula><tex-math>$C$</tex-math></inline-formula>-configured second-order common-mode APN with its two inductors respectively replaced by two transmission lines. In this work, the TL-based QAPN is, for the first time, analyzed in the context of phase-shifter design. Through the analysis, the conditions for the TL-based QAPN to exhibit zero reflection and the design equations are derived. Two generic switched-network phase-shifter topologies incorporating the TL-based QAPNs are investigated. For experimental verification, a Ka/Q-band 5-bit phase shifter is designed and realized in a 90-nm CMOS technology. The design procedure for using the TL-based QAPN as a phase-shifting bit is described. The measured RMS phase and amplitude errors of the 5-bit phase shifter are less than 4<inline-formula><tex-math>$^{circ }$</tex-math></inline-formula> and 0.3 dB, respectively, from 29.0 to 45.1 GHz, which translates into a bandwidth of 43.5%. The performance is among the best results in the literature, demonstrating the usefulness of the proposed TL-based QAPN in phase-shifter design.","PeriodicalId":93296,"journal":{"name":"IEEE journal of microwaves","volume":"5 2","pages":"462-475"},"PeriodicalIF":6.9,"publicationDate":"2025-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10910119","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143655003","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Simultaneous Localization and Mapping (SLAM) for Room Exploration Using Ultrawideband Millimeterwave FMCW Radar","authors":"Tobias Körner;Aman Batra;Thomas Kaiser;Nils Pohl;Christian Schulz;Ilona Rolfes;Jan Barowski","doi":"10.1109/JMW.2025.3541789","DOIUrl":"https://doi.org/10.1109/JMW.2025.3541789","url":null,"abstract":"<underline>S</u>imultaneous <underline>L</u>ocalization <underline>a</u>nd <underline>M</u>apping (SLAM) of indoor scenarios is usually based on camera or lidar sensors as data sources. However, radar based room scanning offers several complementary advantages to these systems. Among other features, radar sensors are more robust to optical opacities, for example, those caused by smoke and dust in emergency scenarios or in harsh environments. Furthermore, the coherent measurement principle of radar sensors provides highly precise distance information that can be utilized to track the exact position and dimensions of the visible objects. In contrast to camera and lidar, radar applications in room exploration are up to now limited by reduced spatial, i.e. mostly angular/lateral, resolution. This is due to the comparably large wavelength of the utilized signals. This work demonstrates the capabilities of ultrawideband millimeterwave <underline>F</u>requency <underline>M</u>odulated <underline>C</u>ontinuous <underline>W</u>ave (FMCW) radar sensors operating around 80 GHz in conjunction with the <underline>S</u>ynthetic <underline>A</u>perture <underline>R</u>adar (SAR) imaging method. To allow imaging whilst moving, self-localization techniques based on sub-aperture processing are evaluated. Therefore, we demonstrate a detailed mapping procedure for room exploration applications by exploiting large absolute bandwidths of more than 20 GHz with high resolution imaging techniques on a mobile robot platform.","PeriodicalId":93296,"journal":{"name":"IEEE journal of microwaves","volume":"5 2","pages":"344-355"},"PeriodicalIF":6.9,"publicationDate":"2025-03-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10909660","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143654913","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An Electronically Reconfigurable Magnetic Metasurface for Enhanced Low-Frequency Wireless Power Transfer Applications","authors":"Martina Falchi;Angelica Masi;Pierpaolo Usai;Agostino Monorchio;Danilo Brizi","doi":"10.1109/JMW.2025.3539953","DOIUrl":"https://doi.org/10.1109/JMW.2025.3539953","url":null,"abstract":"Resonant inductive Wireless Power Transfer (WPT) offers a practical solution for supplying energy to consumer, industrial and medical devices. However, conventional WPT systems face severe limitations if one is interested to the dynamic and arbitrary control of the magnetic field distribution. Consequently, our paper explores the design and implementation of an electronically reconfigurable 5×5 magnetic metasurface for low-frequency WPT applications, operating at 3 MHz. The reconfigurable array is excited by a resonant transmitting coil operating in its near-field region. Through an analytical approach, the metasurface operation can be arbitrarily driven, obtaining the unit-cells current distribution which optimally reshapes the magnetic field for a desired application. In addition, the method also enables the precise determination of capacitive loads of each unit-cell for effectively synthetizing the metasurface response. Then, the reconfigurability process is accomplished by integrating varactor diodes within each unit-cell, providing real-time control of the currents pattern across the metasurface according to the analytical approach outputs. Finally, numerical simulations and experimental measurements on a fabricated prototype are presented, fully demonstrating the system's capability to efficiently switch between arbitrary configurations, either concentrating the magnetic field in specific areas or creating a uniform distribution. This dynamic adaptability addresses important challenges in WPT, such as reduction in alignment sensitivity and efficiency loss over distance, with enhanced flexibility, reliability, and safety.","PeriodicalId":93296,"journal":{"name":"IEEE journal of microwaves","volume":"5 2","pages":"312-321"},"PeriodicalIF":6.9,"publicationDate":"2025-03-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10908628","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143654895","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Advanced Millimeter Wave Radar-Based Human Pose Estimation Enabled by a Deep Learning Neural Network Trained With Optical Motion Capture Ground Truth Data","authors":"Lukas Engel;Jonas Mueller;Eduardo Javier Feria Rendon;Eva Dorschky;Daniel Krauss;Ingrid Ullmann;Bjoern M. Eskofier;Martin Vossiek","doi":"10.1109/JMW.2025.3535525","DOIUrl":"https://doi.org/10.1109/JMW.2025.3535525","url":null,"abstract":"This paper presents a deep learning-enabled method for human pose estimation using radar target lists, obtained through a low-cost radar system with three transmitters and four receivers in a multiple-input multiple-output setup. We address challenges in previous research that often relied on extracting ground truth poses from RGB data, which are constrained by the need for 3D mapping and vulnerability to occlusions. To overcome these limitations, we utilized optical motion capture, which is widely recognized as the gold standard for precise human motion analysis. We conducted an extensive optical motion capture study involving various recorded movement activities, which resulted in <italic>mmRadPose</i>, a new dataset that enhances existing benchmarks for radar-based pose estimation. This dataset has been made publicly accessible. Building on this approach, we designed an application-tailored radar signal processing chain to generate suitable input for the machine learning algorithm. We further developed an attentional recurrent-based deep learning model, <italic>PntPoseAT</i>, which predicts 24 keypoints of human poses using radar target lists. We employed cross validation to thoroughly evaluate the model. This model surpasses previous approaches and achieves an average mean per-joint position error of <inline-formula><tex-math>$6.49 ,mathrm{c}mathrm{m}$</tex-math></inline-formula> with a standard deviation of <inline-formula><tex-math>$3.74 ,mathrm{c}mathrm{m}$</tex-math></inline-formula> on totally unseen test data. This excellent accuracy of the reconstructed keypoint positions is particularly remarkable when you consider that a very simple radar was used for the measurements. Additionally, we conducted a comprehensive analysis of the model's performance by exploring aspects such as network architecture, the use of long short-term memory versus gated recurrent units, input data selection, and the integration of multi-head self-attention mechanisms.","PeriodicalId":93296,"journal":{"name":"IEEE journal of microwaves","volume":"5 2","pages":"373-387"},"PeriodicalIF":6.9,"publicationDate":"2025-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10904474","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143655019","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Multipactor Breakdown Threshold Estimation Based on Circuital Models and Particle Simulations for Multicarrier Signals in RF Filters","authors":"Miguel Rodríguez;Raúl Cervera;Carlos Alcaide;Pablo González;Pablo Soto;José V. Morro;Vicente E. Boria;César Miquel España;David Raboso","doi":"10.1109/JMW.2025.3533026","DOIUrl":"https://doi.org/10.1109/JMW.2025.3533026","url":null,"abstract":"Multipactor is a harmful effect that may challenge the correct operation of satellite communication systems by limiting the system power-handling capability, and hence its overall performance. Therefore, the development of techniques for predicting the multipactor threshold is of great practical interest. For narrowband components, rough estimations can be obtained from experimental charts, normally resulting in conservative thresholds. More accurate predictions can be obtained with particle simulators, at the expense of a much higher computational effort. This study proposes an approach based on circuital models for swift and accurate multipactor threshold predictions, specifically addressing short-term discharges induced by multicarrier signals in narrowband samples. The use of reduced, but representative, electromagnetic (EM) models of the critical gap region is discussed in detail. Through the use of these models, it is possible to avoid simulating the complete structure, increasing the computational efficiency and enabling the fulfillment of the power requirements at early design stages. The proposed technique is validated through commercial particle simulators, showcasing its efficacy, efficiency, and key benefits.","PeriodicalId":93296,"journal":{"name":"IEEE journal of microwaves","volume":"5 2","pages":"438-450"},"PeriodicalIF":6.9,"publicationDate":"2025-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10904461","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143655081","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Unitary Condition, Group Delay and Quality Factor in Microwave Filters","authors":"Ali Kheirdoost;Maysam Haghparast;Behzad Ahmadi;Matteo Oldoni","doi":"10.1109/JMW.2025.3538856","DOIUrl":"https://doi.org/10.1109/JMW.2025.3538856","url":null,"abstract":"In this paper, the unitary condition of scattering parameters for lossless and lossy filters is investigated. The primary objective is to establish a mathematical framework that explains the limitations observed in filter amplitude response sharpness at passband edges during practical measurements. It is achieved by analytically evaluating the unitary condition using a closed form coupling matrix model. Various numerical examples are presented to demonstrate the impact of loss on the unitary condition and filter sharpness in practical scenarios. Moreover, we propose a mathematical form of the T term based on the extension to the unitary condition, serving as a gauge to quantify the rounded passband edges in filter response. This T term is related to filter design parameters and the resonators' quality factor, enabling a deeper understanding of filter performance in real-world conditions. The developed theory implication is discussed in analyzing the measurement results of three different filter in different frequency bands.","PeriodicalId":93296,"journal":{"name":"IEEE journal of microwaves","volume":"5 2","pages":"451-461"},"PeriodicalIF":6.9,"publicationDate":"2025-02-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10904455","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143654855","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Synthesized Design of Millimeter-Wave Low-Loss Wideband Bandpass Filter and Filtering Impedance Transformer in 90-nm (Bi)-CMOS Technology","authors":"Xiaolong Huang;Zheng Liu;Emir Ali Karahan;Kaushik Sengupta","doi":"10.1109/JMW.2025.3532217","DOIUrl":"https://doi.org/10.1109/JMW.2025.3532217","url":null,"abstract":"This paper introduces a rapid filter synthesis method that utilizes the improved Chebyshev function to design versatile broadband on-chip filters with multiple (N) independently controlled transmission zeros (TZs). It eliminates the constraints of narrow bandwidth associated with traditional filter synthesis method. A set of three universal lumped LC circuit topologies are proposed to achieve arbitrary bandwidth, arbitrary order, and different distributions of N TZs. Additionally, we introduce an innovative approach to simultaneously extract components from both sides of the circuit during lumped LC circuit synthesis, which reduces accumulated numerical errors and improves the design speed. Several filters with the same 50–70 GHz passband but different TZs distributions, and an ultra-wideband filter from 30–90 GHz are successfully synthesized using the proposed circuit topologies and extraction method. Our proposed method can also be extended to design filtering impedance transformers for on-chip systems that surpasses the traditional RF design flow using 50 Ω interface and offers the combined benefits of component reduction and minimized system loss. Using the proposed design methodology, we fabricated a 90-nm SiGe BiCMOS on-chip filter which exhibits a low insertion loss of 1.5 dB at 59.16 GHz and a fractional bandwidth of 34%, achieving one of the best reported loss performances among silicon integrated filters to date. This research contributes to low-loss on-chip filter design methodology for universal design specifications and offers a design tool that can achieve high design speed and desired performance, enabling the promise of on-chip filter synthesis for emerging wireless technologies.","PeriodicalId":93296,"journal":{"name":"IEEE journal of microwaves","volume":"5 2","pages":"487-502"},"PeriodicalIF":6.9,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10892641","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143654911","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Inverse Rendering of Near-Field mmWave MIMO Radar for Material Reconstruction","authors":"Nikolai Hofmann;Vanessa Wirth;Johanna Bräunig;Ingrid Ullmann;Martin Vossiek;Tim Weyrich;Marc Stamminger","doi":"10.1109/JMW.2025.3535077","DOIUrl":"https://doi.org/10.1109/JMW.2025.3535077","url":null,"abstract":"Near-field multiple-input multiple-output (MIMO) radar systems allow for high-resolution spatial imaging by leveraging multiple antennas to transmit and receive signals across multiple perspectives. This capability is particularly advantageous in challenging environments, where optical imaging techniques struggle. We present a novel approach to inverse rendering for near-field MIMO radar systems, aimed at reconstructing material properties such as surface roughness, dielectric constants, and conductivity from radar and ground-truth mesh data, for example obtained from multi-view stereo. Drawing inspiration from physically based rendering techniques in computer graphics, we formalize an advanced inverse rendering algorithm that integrates electromagnetic wave propagation models directly into the optimization process. To avoid bias from conventional radar image reconstruction algorithms in the optimization process, we directly derive gradients from raw radar outputs, resulting in more accurate material characterization. We validate our approach through extensive experiments on both synthetic and real radar datasets, demonstrating its effectiveness in a multitude of scenarios.","PeriodicalId":93296,"journal":{"name":"IEEE journal of microwaves","volume":"5 2","pages":"356-372"},"PeriodicalIF":6.9,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10892639","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143655011","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"In Vitro Epithelial Lung Cell Vitality Measurements With mm-Waves","authors":"Philipp Hinz;Adrian Diepolder;Giorgio Fois;Manfred Frick;Christian Damm","doi":"10.1109/JMW.2025.3527900","DOIUrl":"https://doi.org/10.1109/JMW.2025.3527900","url":null,"abstract":"This work presents details of a novel measurement approach in the mm-wave range which enables the measurement of epithelial lung cells under <italic>in vitro</i> conditions. The setup is able to perform contact- and interaction-free measurements, while providing an air-liquid interface for fully-differentiated human airway epithelial primary cells. The measurement setup is adapted to the biologic state-of-the-art cultivation environment of these cells. Therefore, all relevant components of this environment are discussed regarding their electromagnetic impact on the measurement. The utilized culture media are electrically characterized at <inline-formula><tex-math>$37 ,mathrm{^{circ }C}$</tex-math></inline-formula>. Planar resonators are employed as a sensor structure to translate changes within the cell layer to an electric response. The design process of the resonators is discussed, and a lumped-element model is established and fitted to measured data for evaluating the results. The fabrication process of the sensor structures is verified both biologically and electrically. A dielectric waveguide is utilized to perform temperature-compensated reflection measurements of the sensor structure. First measurement results of epithelial lung cells in the J-band from <inline-formula><tex-math>$220 ,mathrm{G}mathrm{Hz}$</tex-math></inline-formula> to <inline-formula><tex-math>$325 ,mathrm{G}mathrm{Hz}$</tex-math></inline-formula> are presented.","PeriodicalId":93296,"journal":{"name":"IEEE journal of microwaves","volume":"5 2","pages":"257-268"},"PeriodicalIF":6.9,"publicationDate":"2025-02-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10878488","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143654892","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}