High-coherent microwave pulse accumulation enables the significant enhancement of faint target detection capability. With the urban low-altitude economy burgeoning, pulse detection sources with long-term stability and flexibly encodable interpulse phase are effective in addressing increasingly complex electromagnetic environments. Optoelectronic oscillators (OEOs) are typical high-$Q$ dissipative nonlinear resonant loops, which provide excellent testbeds for microwave temporal dissipative soliton (MTDS) generation with ultrashort pulse widths and ultrahigh coherence. Here, we propose a novel paradigm for achieving interpulse phase control of MTDSs in an externally excited time-delayed coupled OEO loop. Through employing amplitude-encoded sawtooth-wave pulses as the excitation signal, both synchronous and asynchronous pulsating of the MTDSs is achieved, enabling precise interpulse phase control in the nonlinear OEO loop. The simulation and experimental results reveal the approximately linear mapping relationship between the excitation amplitude difference and the interpulse phase with a tunable range over 0–$2pi $ . Significantly, the coherent accumulation results in excellent suppression ratios of the external interference signal, and the noise floor indicates the good coherence and phase stability of the generated pulses, which provides a robust solution for phase-programmable coherent microwave pulse generation in high-performance target detection.
{"title":"Microwave Pulse Train Generation With Flexibly Controllable Interpulse Phase in Time-Delayed Coupled Broadband Optoelectronic Oscillator","authors":"Huan Tian;Li Su;Weiqiang Lyu;Ziwei Xu;Wei Du;Yujia Li;Lingjie Zhang;Zhiyao Zhang;Yong Liu;Tao Zhu","doi":"10.1109/TMTT.2025.3631010","DOIUrl":"https://doi.org/10.1109/TMTT.2025.3631010","url":null,"abstract":"High-coherent microwave pulse accumulation enables the significant enhancement of faint target detection capability. With the urban low-altitude economy burgeoning, pulse detection sources with long-term stability and flexibly encodable interpulse phase are effective in addressing increasingly complex electromagnetic environments. Optoelectronic oscillators (OEOs) are typical high-<inline-formula> <tex-math>$Q$ </tex-math></inline-formula> dissipative nonlinear resonant loops, which provide excellent testbeds for microwave temporal dissipative soliton (MTDS) generation with ultrashort pulse widths and ultrahigh coherence. Here, we propose a novel paradigm for achieving interpulse phase control of MTDSs in an externally excited time-delayed coupled OEO loop. Through employing amplitude-encoded sawtooth-wave pulses as the excitation signal, both synchronous and asynchronous pulsating of the MTDSs is achieved, enabling precise interpulse phase control in the nonlinear OEO loop. The simulation and experimental results reveal the approximately linear mapping relationship between the excitation amplitude difference and the interpulse phase with a tunable range over 0–<inline-formula> <tex-math>$2pi $ </tex-math></inline-formula>. Significantly, the coherent accumulation results in excellent suppression ratios of the external interference signal, and the noise floor indicates the good coherence and phase stability of the generated pulses, which provides a robust solution for phase-programmable coherent microwave pulse generation in high-performance target detection.","PeriodicalId":13272,"journal":{"name":"IEEE Transactions on Microwave Theory and Techniques","volume":"74 2","pages":"1800-1811"},"PeriodicalIF":4.5,"publicationDate":"2025-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146154434","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-12DOI: 10.1109/TMTT.2025.3627908
Shaofeng Zhang;Xiangjin Ma;Jiaqi Han;Qifan Li;Song Zhang;Zhenyu Liu;Yicen Li;Haixia Liu;Long Li
This article presents an amplitude-/phase-independent programmable metasurface (A/PIPMS) that achieves decoupled transmission-amplitude and phase control using only embedded p-i-n diodes. The unit-cell features two U-slot patches serving as receiver and transmitter, with a p-i-namp and two p-i-nphs diodes integrated into their respective layers. Leveraging dynamic impedance embedding (DIE) technology, amplitude and phase modulation of transmission are achieved by controlling the magnitude and direction of the dc within these embedded p-i-n diodes. A rectangular waveguide experiment was performed to further validate the effectiveness of the proposed unit element. The experimental results show that a 1-bit phase resolution and 3-bit amplitude resolution are achieved from 5.6 to 5.8 GHz. To further verify the effectiveness of DIE technology, we fabricate a $16times 16$ unit-cell array prototype and performed measurements in a standard microwave anechoic chamber. Experimental results show that the A/PIPMS achieves beam scanning up to 55° and a programmable low sidelobe pattern. In addition, Ring-Airy beams with different curvatures are realized to provide dynamic focal distances and obstacle-avoidance regions for wireless power transfer (WPT) scenarios. The communication and WPT links are also established and verified, respectively. These results demonstrate that the proposed A/PIPMS offers a promising beamforming solution for simultaneous wireless information and power transfer (SWIPT) in low-altitude uncrewed aerial vehicle (UAV) scenarios.
{"title":"Dynamic Impedance Embedding Amplitude-/Phase-Independent Programmable Metasurface for SWIPT Beamforming","authors":"Shaofeng Zhang;Xiangjin Ma;Jiaqi Han;Qifan Li;Song Zhang;Zhenyu Liu;Yicen Li;Haixia Liu;Long Li","doi":"10.1109/TMTT.2025.3627908","DOIUrl":"https://doi.org/10.1109/TMTT.2025.3627908","url":null,"abstract":"This article presents an amplitude-/phase-independent programmable metasurface (A/PIPMS) that achieves decoupled transmission-amplitude and phase control using only embedded p-i-n diodes. The unit-cell features two U-slot patches serving as receiver and transmitter, with a p-i-n<sub>amp</sub> and two p-i-n<sub>phs</sub> diodes integrated into their respective layers. Leveraging dynamic impedance embedding (DIE) technology, amplitude and phase modulation of transmission are achieved by controlling the magnitude and direction of the dc within these embedded p-i-n diodes. A rectangular waveguide experiment was performed to further validate the effectiveness of the proposed unit element. The experimental results show that a 1-bit phase resolution and 3-bit amplitude resolution are achieved from 5.6 to 5.8 GHz. To further verify the effectiveness of DIE technology, we fabricate a <inline-formula> <tex-math>$16times 16$ </tex-math></inline-formula> unit-cell array prototype and performed measurements in a standard microwave anechoic chamber. Experimental results show that the A/PIPMS achieves beam scanning up to 55° and a programmable low sidelobe pattern. In addition, Ring-Airy beams with different curvatures are realized to provide dynamic focal distances and obstacle-avoidance regions for wireless power transfer (WPT) scenarios. The communication and WPT links are also established and verified, respectively. These results demonstrate that the proposed A/PIPMS offers a promising beamforming solution for simultaneous wireless information and power transfer (SWIPT) in low-altitude uncrewed aerial vehicle (UAV) scenarios.","PeriodicalId":13272,"journal":{"name":"IEEE Transactions on Microwave Theory and Techniques","volume":"74 2","pages":"1861-1873"},"PeriodicalIF":4.5,"publicationDate":"2025-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146154449","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A wireless repeater system based on a reconfigurable intelligent surface (RIS) is proposed, which features low-power control, intelligent computation, and Wi-Fi connectivity. The RIS employs a 2-bit reconfigurable reflectarray (RRA) with two radio frequency (RF) switches to control the current path of each element for 2-bit phase shifting. A distributed and integrated control scheme is adopted, dividing the RRA into multiple regions with predefined power and signal lines, reducing control complexity and allowing operation with only a single power supply. A dedicated main–secondary RIS control system is developed for efficient and flexible control, based on a heterogeneous field-programmable gate array (FPGA)-ESP32 architecture. Besides, a custom-designed software based on a state-machine model with a dedicated attention (AT) command set for the RIS data repeater is proposed. As a proof of concept, a RIS-based wireless repeater with a $20times 20$ RRA was fabricated and tested, achieving 18.3 dBi gain and ±60° beam scanning. Experiments are conducted to evaluate the real-time beam reconstruction capability, with the entire process taking 900950 ms. The system is further validated through quadrature phase shift keying (QPSK) communication at a carrier frequency of 11.3 GHz over a distance of 100 m, achieving a maximum data rate of 10 Mbps. The proposed RIS-based wireless repeater is a promising solution for various applications, including vehicular networks, low-altitude platforms, and smart agriculture.
{"title":"An X-Band Wireless Repeater Based on Reconfigurable Intelligent Surface With Control, Computing, and Networking","authors":"Chenyang Meng;Zhendong Wang;Jun Yang;Hao Chen;Yin Li;Guangyin Feng;Xiu Yin Zhang","doi":"10.1109/TMTT.2025.3628385","DOIUrl":"https://doi.org/10.1109/TMTT.2025.3628385","url":null,"abstract":"A wireless repeater system based on a reconfigurable intelligent surface (RIS) is proposed, which features low-power control, intelligent computation, and Wi-Fi connectivity. The RIS employs a 2-bit reconfigurable reflectarray (RRA) with two radio frequency (RF) switches to control the current path of each element for 2-bit phase shifting. A distributed and integrated control scheme is adopted, dividing the RRA into multiple regions with predefined power and signal lines, reducing control complexity and allowing operation with only a single power supply. A dedicated main–secondary RIS control system is developed for efficient and flexible control, based on a heterogeneous field-programmable gate array (FPGA)-ESP32 architecture. Besides, a custom-designed software based on a state-machine model with a dedicated attention (AT) command set for the RIS data repeater is proposed. As a proof of concept, a RIS-based wireless repeater with a <inline-formula> <tex-math>$20times 20$ </tex-math></inline-formula> RRA was fabricated and tested, achieving 18.3 dBi gain and ±60° beam scanning. Experiments are conducted to evaluate the real-time beam reconstruction capability, with the entire process taking 900950 ms. The system is further validated through quadrature phase shift keying (QPSK) communication at a carrier frequency of 11.3 GHz over a distance of 100 m, achieving a maximum data rate of 10 Mbps. The proposed RIS-based wireless repeater is a promising solution for various applications, including vehicular networks, low-altitude platforms, and smart agriculture.","PeriodicalId":13272,"journal":{"name":"IEEE Transactions on Microwave Theory and Techniques","volume":"74 2","pages":"2023-2034"},"PeriodicalIF":4.5,"publicationDate":"2025-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146154473","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-11DOI: 10.1109/TMTT.2025.3628636
Zhouyang Pan;Dan Zhu;Yanghaolin Cao;Ping Li;Fuhui Zhou;Shilong Pan
Radar modulation and state recognition for multifunction radar (MFR) play a vital role in electronic warfare systems. However, in wideband scenarios, traditional digital radar recognition systems are challenged by the massive data volume, making it difficult to achieve wideband, real-time, and high-precision recognition. To address this challenge, a photonics-based parameter measurement model is proposed to simultaneously map time, phase, and frequency parameters of wideband radar signals into low-rate electrical measurement pulses, whose amplitude and timing features are used for radar feature extraction. A two-stage learning back-end is introduced to automatically classify the radar states. By uniting the ultrafast photonics-based feature extraction front-end with the attention-driven neural inference, the proposed system transcends digitization limits and maximizes situational-awareness accuracy. A proof-of-concept experiment is conducted. The proposed work successfully recognizes nine modulation types and five states within a 19–29-GHz frequency range, with SNR varying from −20 to 19 dB. The required sampling rate is significantly reduced from 58 GSa/s to 150 MSa/s, and the computational complexity is reduced from 26 427 to 64.98 GFLOPs.
{"title":"Photonics-Based Automatic Modulation and State Recognition System for Multifunction Radar","authors":"Zhouyang Pan;Dan Zhu;Yanghaolin Cao;Ping Li;Fuhui Zhou;Shilong Pan","doi":"10.1109/TMTT.2025.3628636","DOIUrl":"https://doi.org/10.1109/TMTT.2025.3628636","url":null,"abstract":"Radar modulation and state recognition for multifunction radar (MFR) play a vital role in electronic warfare systems. However, in wideband scenarios, traditional digital radar recognition systems are challenged by the massive data volume, making it difficult to achieve wideband, real-time, and high-precision recognition. To address this challenge, a photonics-based parameter measurement model is proposed to simultaneously map time, phase, and frequency parameters of wideband radar signals into low-rate electrical measurement pulses, whose amplitude and timing features are used for radar feature extraction. A two-stage learning back-end is introduced to automatically classify the radar states. By uniting the ultrafast photonics-based feature extraction front-end with the attention-driven neural inference, the proposed system transcends digitization limits and maximizes situational-awareness accuracy. A proof-of-concept experiment is conducted. The proposed work successfully recognizes nine modulation types and five states within a 19–29-GHz frequency range, with SNR varying from −20 to 19 dB. The required sampling rate is significantly reduced from 58 GSa/s to 150 MSa/s, and the computational complexity is reduced from 26 427 to 64.98 GFLOPs.","PeriodicalId":13272,"journal":{"name":"IEEE Transactions on Microwave Theory and Techniques","volume":"74 2","pages":"1770-1779"},"PeriodicalIF":4.5,"publicationDate":"2025-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146154452","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-11DOI: 10.1109/TMTT.2025.3622320
Dantong Liu;Zehao Zhang;Yifeng Wang;Yunxiao Zhao;Qizhi Wang;Yuanming Shi;Pingqiang Zhou;Xiong Wang
Cerebral disease has always been a major threat to human health, of which hemorrhagic stroke poses one of the greatest dangers. As a novel imaging modality, microwave-induced thermoacoustic tomography (MITAT) serves as a potential noninvasive, time and cost-effective technique to detect cerebral diseases. However, the traditional MITAT technique can only provide qualitative rather than quantitative information of tissues, which limits biomedical applications of MITAT. In this article, a deep-learning-enabled MITAT (DL-MITAT) brain imaging approach is presented to perform transcranial quantitative dual reconstruction of dielectric and acoustic properties of the brain tissues. We design a novel network architecture to extract the tissue properties and mitigate the acoustic inhomogeneity issue caused by the skull. With sufficient simulation and ex vivo experimental testing, we demonstrate that this method can effectively recover the quantitative dielectric constant, conductivity, and speed of sound (SOS) distributions of the applied brain models in a transcranial manner. Different cases are studied to test the generalization ability of the proposed approach. This is the first reported work that can simultaneously and quantitatively reconstruct both the dielectric and acoustic properties. This work provides a viable pathway for transcranial quantitative reconstruction of brain tissues’ dielectric properties and SOS, which is very meaningful for cerebral disease diagnosis. The proposed DL-MITAT technique holds the potential to alleviate the acoustic distortion issue due to the skull-induced acoustic inhomogeneity.
{"title":"Deep-Learning-Based Transcranial Quantitative Microwave-Induced Thermoacoustic Tomography for Dual Reconstruction of Dielectric and Acoustic Properties","authors":"Dantong Liu;Zehao Zhang;Yifeng Wang;Yunxiao Zhao;Qizhi Wang;Yuanming Shi;Pingqiang Zhou;Xiong Wang","doi":"10.1109/TMTT.2025.3622320","DOIUrl":"https://doi.org/10.1109/TMTT.2025.3622320","url":null,"abstract":"Cerebral disease has always been a major threat to human health, of which hemorrhagic stroke poses one of the greatest dangers. As a novel imaging modality, microwave-induced thermoacoustic tomography (MITAT) serves as a potential noninvasive, time and cost-effective technique to detect cerebral diseases. However, the traditional MITAT technique can only provide qualitative rather than quantitative information of tissues, which limits biomedical applications of MITAT. In this article, a deep-learning-enabled MITAT (DL-MITAT) brain imaging approach is presented to perform transcranial quantitative dual reconstruction of dielectric and acoustic properties of the brain tissues. We design a novel network architecture to extract the tissue properties and mitigate the acoustic inhomogeneity issue caused by the skull. With sufficient simulation and ex vivo experimental testing, we demonstrate that this method can effectively recover the quantitative dielectric constant, conductivity, and speed of sound (SOS) distributions of the applied brain models in a transcranial manner. Different cases are studied to test the generalization ability of the proposed approach. This is the first reported work that can simultaneously and quantitatively reconstruct both the dielectric and acoustic properties. This work provides a viable pathway for transcranial quantitative reconstruction of brain tissues’ dielectric properties and SOS, which is very meaningful for cerebral disease diagnosis. The proposed DL-MITAT technique holds the potential to alleviate the acoustic distortion issue due to the skull-induced acoustic inhomogeneity.","PeriodicalId":13272,"journal":{"name":"IEEE Transactions on Microwave Theory and Techniques","volume":"73 12","pages":"10632-10643"},"PeriodicalIF":4.5,"publicationDate":"2025-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145778254","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This article presents a 28-GHz four-element blocker-tolerant digital receiver (RX) array. Each RX achieves high out-of-band (OOB) blocker tolerance with negligible performance and power penalty by utilizing a highly linear, single-stage inverter low-noise amplifier (LNA), followed by an $N$ -path mixer with tunable filtering properties and a baseband (BB) transimpedance amplifier (TIA) for linearity enhancement. Several mm-Wave RXs and LNAs architectures are presented and compared, and mm-Wave $N$ -path mixers design tradeoffs are discussed. The RX array chip was fabricated in TSMC 65-nm CMOS process, occupying an active area of $6.44~text {mm}^{2}$ . The chip was mounted on a custom board with patch antennas for system measurements. In our implementation, each RX achieves a <4-dB noise figure (NF), with an RX gain of 40-dB per chain, in-band (IB) IIP3 of −20- and −3.5-dBm B1dB at a 500-MHz offset, while drawing a total power of 85.8 mW, at a frequency range of 22–31 GHz. Dynamic measurements with modulated IB and an OOB signals demonstrate −40-dB error vector magnitude (EVM) for −12-dBm blocker power. Over-the-air (OTA) measurements showcase up to ±60° reception angle, with spatial tolerance achieved with beam-nulling capability, improving signal-to-interference-and-noise ratio (SINR) from −6 to 31 dB.
{"title":"A 65-nm CMOS mm-Wave Blocker-Tolerant Digital Receiver Array","authors":"Erez Zolkov;Yuval Ginzberg;Nimrod Ginzberg;Emanuel Cohen","doi":"10.1109/TMTT.2025.3628958","DOIUrl":"https://doi.org/10.1109/TMTT.2025.3628958","url":null,"abstract":"This article presents a 28-GHz four-element blocker-tolerant digital receiver (RX) array. Each RX achieves high out-of-band (OOB) blocker tolerance with negligible performance and power penalty by utilizing a highly linear, single-stage inverter low-noise amplifier (LNA), followed by an <inline-formula> <tex-math>$N$ </tex-math></inline-formula>-path mixer with tunable filtering properties and a baseband (BB) transimpedance amplifier (TIA) for linearity enhancement. Several mm-Wave RXs and LNAs architectures are presented and compared, and mm-Wave <inline-formula> <tex-math>$N$ </tex-math></inline-formula>-path mixers design tradeoffs are discussed. The RX array chip was fabricated in TSMC 65-nm CMOS process, occupying an active area of <inline-formula> <tex-math>$6.44~text {mm}^{2}$ </tex-math></inline-formula>. The chip was mounted on a custom board with patch antennas for system measurements. In our implementation, each RX achieves a <4-dB noise figure (NF), with an RX gain of 40-dB per chain, in-band (IB) IIP3 of −20- and −3.5-dBm B1dB at a 500-MHz offset, while drawing a total power of 85.8 mW, at a frequency range of 22–31 GHz. Dynamic measurements with modulated IB and an OOB signals demonstrate −40-dB error vector magnitude (EVM) for −12-dBm blocker power. Over-the-air (OTA) measurements showcase up to ±60° reception angle, with spatial tolerance achieved with beam-nulling capability, improving signal-to-interference-and-noise ratio (SINR) from −6 to 31 dB.","PeriodicalId":13272,"journal":{"name":"IEEE Transactions on Microwave Theory and Techniques","volume":"74 2","pages":"1981-1993"},"PeriodicalIF":4.5,"publicationDate":"2025-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146154470","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-10DOI: 10.1109/TMTT.2025.3627440
Francesco Lestini;Alessandro DiCarlofelice;Piero Tognolatti;Gaetano Marrocco;Cecilia Occhiuzzi
This article introduces a passive reconfiguration strategy for RF networks based on radio frequency identification (RFID) integrated circuits (ICs) embedded within guided-wave structures. Each RFID IC is repurposed as a batteryless, addressable dc voltage source capable of biasing RF components, such as varactors and GaAs switches. Unlike conventional over-the-air (OTA) architectures, the proposed approach eliminates tag antennas by integrating the ICs directly into microwave transmission lines, where power, control, and signal share the same RF path. A dedicated multichip test platform is developed to experimentally characterize the IC behavior in this novel configuration, evaluating impedance variation, activation thresholds, and output stability. Measurements on a commercial RFID chip demonstrate reliable operation with only −15 dBm of incident RF power, and sufficient dc output to drive over 1000 GaAs SPST switches or 10 000 varactors. To validate the concept, a fully passive, four-element monopole array operating at 900 MHz is demonstrated, where each element is gated by an RFID-controlled SPST switch. The array performs beam steering through selective element activation, using a single RF feed to simultaneously energize the array, power the ICs, and transmit EPC Gen2 control commands.
{"title":"An RFID-Based Guided Control Node for Batteryless Reconfigurable RF Architectures","authors":"Francesco Lestini;Alessandro DiCarlofelice;Piero Tognolatti;Gaetano Marrocco;Cecilia Occhiuzzi","doi":"10.1109/TMTT.2025.3627440","DOIUrl":"https://doi.org/10.1109/TMTT.2025.3627440","url":null,"abstract":"This article introduces a passive reconfiguration strategy for RF networks based on radio frequency identification (RFID) integrated circuits (ICs) embedded within guided-wave structures. Each RFID IC is repurposed as a batteryless, addressable dc voltage source capable of biasing RF components, such as varactors and GaAs switches. Unlike conventional over-the-air (OTA) architectures, the proposed approach eliminates tag antennas by integrating the ICs directly into microwave transmission lines, where power, control, and signal share the same RF path. A dedicated multichip test platform is developed to experimentally characterize the IC behavior in this novel configuration, evaluating impedance variation, activation thresholds, and output stability. Measurements on a commercial RFID chip demonstrate reliable operation with only −15 dBm of incident RF power, and sufficient dc output to drive over 1000 GaAs SPST switches or 10 000 varactors. To validate the concept, a fully passive, four-element monopole array operating at 900 MHz is demonstrated, where each element is gated by an RFID-controlled SPST switch. The array performs beam steering through selective element activation, using a single RF feed to simultaneously energize the array, power the ICs, and transmit EPC Gen2 control commands.","PeriodicalId":13272,"journal":{"name":"IEEE Transactions on Microwave Theory and Techniques","volume":"74 2","pages":"1883-1892"},"PeriodicalIF":4.5,"publicationDate":"2025-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146154457","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A W-band frequency-modulated continuous-wave (FMCW) radar, implemented in 65-nm CMOS, is proposed for intelligent transportation system (ITS) applications in this article. The system integrates four transmitters (TXs) and four receivers (RXs), along with a frequency synthesizer and a local oscillator (LO) distribution network. Both the low-noise amplifier (LNA) and the power amplifier (PA) adopt multistage cascaded topologies with magnetically coupled resonators (MCRs) to enable broadband operation. An ultrawideband class-B mixer, implemented with only an active switching core, supports continuous operation from 20 to 110 GHz. Furthermore, an LO distribution network featuring three cascaded frequency doublers achieves frequency octupling from an 11–13-GHz synthesizer, enabling wide-bandwidth (BW) modulation. Under the default configuration, the four TX and RX channels achieve a maximum TX output power of 13.4 dBm with 12.8% drain efficiency, an RX conversion gain (CG) of 64.4 dB, a minimum RX $text {NF}_{text {ssb}}$ of 8.4 dB, an RX in-band (IB) IP1dB from −49.4 to −43.6 dBm @3 MHz offset, and an RX out-of-band (OOB) IP1dB from −17 to −11.1 dBm at 10-kHz offset across 90–98 GHz. The measured phase noise is −94.06 dBc/Hz at 1-MHz offset with a 90.4-GHz carrier. The root-mean-square (rms) error is 3.52 MHz (0.044%) for a sawtooth chirp with an 8-GHz range and a 20-MHz/$mu $ s chirp rate. Each TX/RX element consumes 208.5/76.5 mW, respectively, and the entire chip occupies a $4.5times 3.8$ mm2 area. To validate the radar operation, a slot substrate-integrated waveguide (SIW) antenna array, with a flip-chip chip-scale package (FCCSP) transceiver, is designed and fabricated on a Rogers 3003G2 PCB. The multiple-input–multiple-output (MIMO) radar prototype achieves a distance resolution of 2.85 cm and an angular resolution of 13° with a field of view (FOV) of 144°.
{"title":"A W-Band FMCW Radar Transceiver Supporting Broadband Modulation in 65-nm CMOS for Intelligent Transportation System Applications","authors":"Shengjie Wang;Jiangbo Chen;Quanyong Li;Jingwen Xu;Wenyan Zhao;Nayu Li;Huaicheng Zhao;Xiaokang Qi;Yen-Cheng Kuan;Gaopeng Chen;Chunyi Song;Qun Jane Gu;Zhiwei Xu","doi":"10.1109/TMTT.2025.3621072","DOIUrl":"https://doi.org/10.1109/TMTT.2025.3621072","url":null,"abstract":"A W-band frequency-modulated continuous-wave (FMCW) radar, implemented in 65-nm CMOS, is proposed for intelligent transportation system (ITS) applications in this article. The system integrates four transmitters (TXs) and four receivers (RXs), along with a frequency synthesizer and a local oscillator (LO) distribution network. Both the low-noise amplifier (LNA) and the power amplifier (PA) adopt multistage cascaded topologies with magnetically coupled resonators (MCRs) to enable broadband operation. An ultrawideband class-B mixer, implemented with only an active switching core, supports continuous operation from 20 to 110 GHz. Furthermore, an LO distribution network featuring three cascaded frequency doublers achieves frequency octupling from an 11–13-GHz synthesizer, enabling wide-bandwidth (BW) modulation. Under the default configuration, the four TX and RX channels achieve a maximum TX output power of 13.4 dBm with 12.8% drain efficiency, an RX conversion gain (CG) of 64.4 dB, a minimum RX <inline-formula> <tex-math>$text {NF}_{text {ssb}}$ </tex-math></inline-formula> of 8.4 dB, an RX in-band (IB) IP1dB from −49.4 to −43.6 dBm @3 MHz offset, and an RX out-of-band (OOB) IP1dB from −17 to −11.1 dBm at 10-kHz offset across 90–98 GHz. The measured phase noise is −94.06 dBc/Hz at 1-MHz offset with a 90.4-GHz carrier. The root-mean-square (rms) error is 3.52 MHz (0.044%) for a sawtooth chirp with an 8-GHz range and a 20-MHz/<inline-formula> <tex-math>$mu $ </tex-math></inline-formula>s chirp rate. Each TX/RX element consumes 208.5/76.5 mW, respectively, and the entire chip occupies a <inline-formula> <tex-math>$4.5times 3.8$ </tex-math></inline-formula> mm2 area. To validate the radar operation, a slot substrate-integrated waveguide (SIW) antenna array, with a flip-chip chip-scale package (FCCSP) transceiver, is designed and fabricated on a Rogers 3003G2 PCB. The multiple-input–multiple-output (MIMO) radar prototype achieves a distance resolution of 2.85 cm and an angular resolution of 13° with a field of view (FOV) of 144°.","PeriodicalId":13272,"journal":{"name":"IEEE Transactions on Microwave Theory and Techniques","volume":"74 1","pages":"1037-1053"},"PeriodicalIF":4.5,"publicationDate":"2025-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146049268","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Microwave dielectric spectroscopy (MDS) is a powerful technique for analyzing the electromagnetic properties of biological substances, offering advantages over lower-frequency methods such as impedometry, which are prone to concentration polarization effects. While flexible MDS sensors and broadband MDS sensors have been independently demonstrated, no prior work has successfully combined both capabilities into a single platform. In this work, we present the first flexible, broadband MDS sensor capable of measuring the complex permittivity of biological liquids directly within their original vials, across a frequency range of 2–$19{,}$ GHz. The novelty of this sensor is enabled by a theoretical framework that describes the excitation of waveguide modes in cylindrical coplanar waveguides (CCPWs). By accurately modeling the influence of these modes on the device’s scattering parameters, we establish a reliable method for extracting the complex permittivity of liquid samples contained within standard laboratory vials. The sensor’s mechanical flexibility allows it to conform to vials of varying shapes and sizes, facilitating noninvasive, contactless measurements. This feature is particularly advantageous for hazardous materials, where minimizing human exposure is essential, and for sensitive biological samples, which are susceptible to contamination if transferred from the containers in which they were originally collected. The proposed sensor addresses key limitations of existing MDS platforms, providing a safe, accurate, and practical solution for broadband dielectric characterization of biological and chemical substances.
{"title":"Broadband Flexible Sensor for Microwave Dielectric Spectroscopy of Liquids in Vials","authors":"Benyamin Harkinezhad;Tomislav Markovic;Robin Evans;Kamran Ghorbani;Efstratios Skafidas;Dominique Schreurs","doi":"10.1109/TMTT.2025.3624149","DOIUrl":"https://doi.org/10.1109/TMTT.2025.3624149","url":null,"abstract":"Microwave dielectric spectroscopy (MDS) is a powerful technique for analyzing the electromagnetic properties of biological substances, offering advantages over lower-frequency methods such as impedometry, which are prone to concentration polarization effects. While flexible MDS sensors and broadband MDS sensors have been independently demonstrated, no prior work has successfully combined both capabilities into a single platform. In this work, we present the first flexible, broadband MDS sensor capable of measuring the complex permittivity of biological liquids directly within their original vials, across a frequency range of 2–<inline-formula> <tex-math>$19{,}$ </tex-math></inline-formula> GHz. The novelty of this sensor is enabled by a theoretical framework that describes the excitation of waveguide modes in cylindrical coplanar waveguides (CCPWs). By accurately modeling the influence of these modes on the device’s scattering parameters, we establish a reliable method for extracting the complex permittivity of liquid samples contained within standard laboratory vials. The sensor’s mechanical flexibility allows it to conform to vials of varying shapes and sizes, facilitating noninvasive, contactless measurements. This feature is particularly advantageous for hazardous materials, where minimizing human exposure is essential, and for sensitive biological samples, which are susceptible to contamination if transferred from the containers in which they were originally collected. The proposed sensor addresses key limitations of existing MDS platforms, providing a safe, accurate, and practical solution for broadband dielectric characterization of biological and chemical substances.","PeriodicalId":13272,"journal":{"name":"IEEE Transactions on Microwave Theory and Techniques","volume":"74 1","pages":"893-904"},"PeriodicalIF":4.5,"publicationDate":"2025-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146049286","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-03DOI: 10.1109/TMTT.2025.3619548
Zehao Zhang;Dantong Liu;Yunxiao Zhao;Hongjia Liu;Guoqiang Liu;Xufeng Kou;Xiong Wang
Transcranial imaging is an indispensable method for the diagnosis of cerebral diseases that are major threats to human health. Microwave-induced thermoacoustic tomography (MITAT) is a promising hybrid technique for nonionizing, noninvasive, and time and cost-effective modality for transcranial imaging with a compact hardware system. Nevertheless, the conventional MITAT technique cannot efficiently deal with the acoustic inhomogeneity issue caused by the skull, which leads to low image quality. Although MITAT combined with deep learning (DL) has shown compelling ability in reconstructing high-quality images in a transcranial manner, the requirement for too many training datasets may hinder potential applications. In this work, we propose a new DL-based MITAT modality that leverages a physics-informed neural network (PINN) to improve the image quality of transcranial imaging using much less training data. The PINN is based on the acoustic reciprocity theorem (ART), and the proposed method is named as DL-MITAT-ART. We perform ex vivo 2-D experimental testing employing intact cynomolgus monkey skulls and blood vessel phantoms. The imaging results demonstrate that the proposed DL-MITAT-ART method can faithfully recover the blood vessel phantoms in a transcranial manner applying only 175 training datasets, more than ten times fewer than those for the traditional DL-MITAT methods. This work provides a novel paradigm for PINN-based MITAT technique for transcranial imaging. It is highly meaningful for cerebral disease diagnosis based on MITAT or ultrasonography and microwave imaging applications involving an inhomogeneous environment.
{"title":"Transcranial Blood Vessel Imaging Through Intact Cynomolgus Monkey Skulls Applying Microwave-Induced Thermoacoustic Tomography Based on a Physics-Informed Neural Network","authors":"Zehao Zhang;Dantong Liu;Yunxiao Zhao;Hongjia Liu;Guoqiang Liu;Xufeng Kou;Xiong Wang","doi":"10.1109/TMTT.2025.3619548","DOIUrl":"https://doi.org/10.1109/TMTT.2025.3619548","url":null,"abstract":"Transcranial imaging is an indispensable method for the diagnosis of cerebral diseases that are major threats to human health. Microwave-induced thermoacoustic tomography (MITAT) is a promising hybrid technique for nonionizing, noninvasive, and time and cost-effective modality for transcranial imaging with a compact hardware system. Nevertheless, the conventional MITAT technique cannot efficiently deal with the acoustic inhomogeneity issue caused by the skull, which leads to low image quality. Although MITAT combined with deep learning (DL) has shown compelling ability in reconstructing high-quality images in a transcranial manner, the requirement for too many training datasets may hinder potential applications. In this work, we propose a new DL-based MITAT modality that leverages a physics-informed neural network (PINN) to improve the image quality of transcranial imaging using much less training data. The PINN is based on the acoustic reciprocity theorem (ART), and the proposed method is named as DL-MITAT-ART. We perform ex vivo 2-D experimental testing employing intact cynomolgus monkey skulls and blood vessel phantoms. The imaging results demonstrate that the proposed DL-MITAT-ART method can faithfully recover the blood vessel phantoms in a transcranial manner applying only 175 training datasets, more than ten times fewer than those for the traditional DL-MITAT methods. This work provides a novel paradigm for PINN-based MITAT technique for transcranial imaging. It is highly meaningful for cerebral disease diagnosis based on MITAT or ultrasonography and microwave imaging applications involving an inhomogeneous environment.","PeriodicalId":13272,"journal":{"name":"IEEE Transactions on Microwave Theory and Techniques","volume":"73 12","pages":"10644-10656"},"PeriodicalIF":4.5,"publicationDate":"2025-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11224392","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145778178","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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