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}
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}
Pub Date : 2025-10-15DOI: 10.1109/TMTT.2025.3617506
Robert C. Crew;Eugene N. Ivanov;Graeme Flower;Michael E. Tobar;Maxim Goryachev
We report a novel X-band loop oscillator, whose resonator is formed from two optimally tuned commercial yttrium iron garnet (YIG) filters. We call this a $Lambda $ -resonator, owing to the characteristic $Lambda $ -shape of its amplitude transfer function (ATF). At offset frequencies greater than 70 Hz, oscillator phase noise is limited by the contribution from the amplifier, as described by Leeson’s model. The effective Q-factor of the $Lambda $ -resonator (2.6 × 103) is determined by the slope of its phase transfer function on resonance, which is directly proportional to the group delay of the filters. With off-the-shelf components, we achieve single-sideband (SSB) phase noise of −151 dBc/Hz at 1 MHz offset for an oscillation frequency of 9.2 GHz. This work points to the potential for improvements with custom built filters optimized for high group delay. The high selectivity of the $Lambda $ -resonator (made of two seventh-order YIG-filters) allowed a strong suppression of both phase and amplitude fluctuations of the transmitted signal at Fourier frequencies outside the resonator’s bandwidth. We also investigated relevant oscillator noise sources, including power-to-frequency conversion as a function of Fourier frequency, and use a novel, highly sensitive technique to characterize the noise.
{"title":"Microwave Oscillator Based on Two Optimally Tuned YIG Filters","authors":"Robert C. Crew;Eugene N. Ivanov;Graeme Flower;Michael E. Tobar;Maxim Goryachev","doi":"10.1109/TMTT.2025.3617506","DOIUrl":"https://doi.org/10.1109/TMTT.2025.3617506","url":null,"abstract":"We report a novel X-band loop oscillator, whose resonator is formed from two optimally tuned commercial yttrium iron garnet (YIG) filters. We call this a <inline-formula> <tex-math>$Lambda $ </tex-math></inline-formula>-resonator, owing to the characteristic <inline-formula> <tex-math>$Lambda $ </tex-math></inline-formula>-shape of its amplitude transfer function (ATF). At offset frequencies greater than 70 Hz, oscillator phase noise is limited by the contribution from the amplifier, as described by Leeson’s model. The effective Q-factor of the <inline-formula> <tex-math>$Lambda $ </tex-math></inline-formula>-resonator (2.6 × 10<sup>3</sup>) is determined by the slope of its phase transfer function on resonance, which is directly proportional to the group delay of the filters. With off-the-shelf components, we achieve single-sideband (SSB) phase noise of −151 dBc/Hz at 1 MHz offset for an oscillation frequency of 9.2 GHz. This work points to the potential for improvements with custom built filters optimized for high group delay. The high selectivity of the <inline-formula> <tex-math>$Lambda $ </tex-math></inline-formula>-resonator (made of two seventh-order YIG-filters) allowed a strong suppression of both phase and amplitude fluctuations of the transmitted signal at Fourier frequencies outside the resonator’s bandwidth. We also investigated relevant oscillator noise sources, including power-to-frequency conversion as a function of Fourier frequency, and use a novel, highly sensitive technique to characterize the noise.","PeriodicalId":13272,"journal":{"name":"IEEE Transactions on Microwave Theory and Techniques","volume":"73 12","pages":"10897-10903"},"PeriodicalIF":4.5,"publicationDate":"2025-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145778171","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 proposes a multibeam-assisted active cross-polarization (X-Pol) suppression technique that leverages auxiliary beams to effectively mitigate X-Pol leakages, thereby supporting polarization-division multiplexing (PDM). Amplitude and phase relationships for optimal cancellation are established, and performance limitations under practical residual array-level errors are quantified through theoretical analysis. To validate the technique, a compact Ka-band 64-element receive (RX) phased array with four fully connected beams is designed and fabricated using an 18-layer printed circuit board (PCB). It integrates 16 eight-channel four-beam beamformers (BFs), a dual-polarized (DP) slot-fed patch antenna array, and four sets of high-isolation 16:1 Wilkinson combining networks. The phased array demonstrates four independently steerable beams with 41.8-dB interbeam isolation at 29.5 GHz. It achieves scanning coverage up to ±50° in both planes with reconfiguration capability between circular [left-handed circular polarization (LHCP)/right-handed circular polarization (RHCP)] and linear (H/V) polarization (Pol) states. The measured gain-to-noise-temperature ratio (G/T) exceeds $mathbf {-7}$ dB/K across all scan angles at 29.5 GHz. Measurement results show that the proposed technique effectively enhances steerable X-Pol discrimination from $mathbf {sim }20$ to $mathbf {gt }40$ dB at the target frequency within a wide bandwidth across the scanning range and significantly improves the error vector magnitude (EVM) under strong interference. To the authors’ best knowledge, this work presents the first Ka-band phased array supporting four concurrent beams with Pol reconfigurability, advancing high-capacity concurrent co-site communication systems with robust interference resilience.
{"title":"Multibeam-Assisted Cross-Polarization Suppression With Ka-Band 64-Element Four-Beam Reconfigurable Phased Array Implementation","authors":"Zixian Ma;Xinhong Xie;Nayu Li;Bing Lan;Haotian Chen;Xiaokang Qi;Chunyi Song;Zhiwei Xu","doi":"10.1109/TMTT.2025.3612979","DOIUrl":"https://doi.org/10.1109/TMTT.2025.3612979","url":null,"abstract":"This article proposes a multibeam-assisted active cross-polarization (X-Pol) suppression technique that leverages auxiliary beams to effectively mitigate X-Pol leakages, thereby supporting polarization-division multiplexing (PDM). Amplitude and phase relationships for optimal cancellation are established, and performance limitations under practical residual array-level errors are quantified through theoretical analysis. To validate the technique, a compact Ka-band 64-element receive (RX) phased array with four fully connected beams is designed and fabricated using an 18-layer printed circuit board (PCB). It integrates 16 eight-channel four-beam beamformers (BFs), a dual-polarized (DP) slot-fed patch antenna array, and four sets of high-isolation 16:1 Wilkinson combining networks. The phased array demonstrates four independently steerable beams with 41.8-dB interbeam isolation at 29.5 GHz. It achieves scanning coverage up to ±50° in both planes with reconfiguration capability between circular [left-handed circular polarization (LHCP)/right-handed circular polarization (RHCP)] and linear (H/V) polarization (Pol) states. The measured gain-to-noise-temperature ratio (G/T) exceeds <inline-formula> <tex-math>$mathbf {-7}$ </tex-math></inline-formula> dB/K across all scan angles at 29.5 GHz. Measurement results show that the proposed technique effectively enhances steerable X-Pol discrimination from <inline-formula> <tex-math>$mathbf {sim }20$ </tex-math></inline-formula> to <inline-formula> <tex-math>$mathbf {gt }40$ </tex-math></inline-formula> dB at the target frequency within a wide bandwidth across the scanning range and significantly improves the error vector magnitude (EVM) under strong interference. To the authors’ best knowledge, this work presents the first Ka-band phased array supporting four concurrent beams with Pol reconfigurability, advancing high-capacity concurrent co-site communication systems with robust interference resilience.","PeriodicalId":13272,"journal":{"name":"IEEE Transactions on Microwave Theory and Techniques","volume":"73 12","pages":"10814-10826"},"PeriodicalIF":4.5,"publicationDate":"2025-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145778120","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 : 2025-10-07DOI: 10.1109/TMTT.2025.3615300
Markku Jokinen;Olli Kursu;Alok Sethi;Rehman Akbar;Zeeshan Siddiqui;Mikko Hietanen;Duccio Delfini;Nuutti Tervo;Janne P. Aikio;Timo Rahkonen;Aarno Pärssinen;Marko E. Leinonen
Array calibration becomes challenging when not only the main lobe gain but also the side lobes become important for interference mitigation from different directions. This article presents an antenna array calibration method that uses multiple variable optimization techniques to calibrate phase errors. A starting point of the calibration method is the radiation pattern without phase calibration. This radiation pattern is set as the target pattern for the phase error search, where phase errors resulting in the best matching radiation pattern are found using simulations to model the antenna array used. The search space increases as a function of the array size, so the multistart search method is used to avoid getting stuck in local optimums. In this article, a prototype millimeter-wave (mmW) antenna array platform is used to verify the functionality of the calibration method. A simulation model of the antenna array is created that can be used for the search. The radiation pattern measurement results show that the proposed method can achieve a similar calibration performance compared with a comprehensive scattering-parameter phase calibration. Comprehensive calibration requires a phase-coherent measurement setup and the control of individual antenna paths. However, the proposed method allows all elements of the antenna array to be active during the calibration measurement, as in the normal operation mode of the array. The method presented uses only amplitude measurement information, simplifying the calibration procedure and measurement setup. Additionally, phase calibration calculations can be performed offline with normal computing hardware.
{"title":"Calibration of 5G Millimeter-Wave Active Antenna Array Platform With Search-Based Optimization Method","authors":"Markku Jokinen;Olli Kursu;Alok Sethi;Rehman Akbar;Zeeshan Siddiqui;Mikko Hietanen;Duccio Delfini;Nuutti Tervo;Janne P. Aikio;Timo Rahkonen;Aarno Pärssinen;Marko E. Leinonen","doi":"10.1109/TMTT.2025.3615300","DOIUrl":"https://doi.org/10.1109/TMTT.2025.3615300","url":null,"abstract":"Array calibration becomes challenging when not only the main lobe gain but also the side lobes become important for interference mitigation from different directions. This article presents an antenna array calibration method that uses multiple variable optimization techniques to calibrate phase errors. A starting point of the calibration method is the radiation pattern without phase calibration. This radiation pattern is set as the target pattern for the phase error search, where phase errors resulting in the best matching radiation pattern are found using simulations to model the antenna array used. The search space increases as a function of the array size, so the multistart search method is used to avoid getting stuck in local optimums. In this article, a prototype millimeter-wave (mmW) antenna array platform is used to verify the functionality of the calibration method. A simulation model of the antenna array is created that can be used for the search. The radiation pattern measurement results show that the proposed method can achieve a similar calibration performance compared with a comprehensive scattering-parameter phase calibration. Comprehensive calibration requires a phase-coherent measurement setup and the control of individual antenna paths. However, the proposed method allows all elements of the antenna array to be active during the calibration measurement, as in the normal operation mode of the array. The method presented uses only amplitude measurement information, simplifying the calibration procedure and measurement setup. Additionally, phase calibration calculations can be performed offline with normal computing hardware.","PeriodicalId":13272,"journal":{"name":"IEEE Transactions on Microwave Theory and Techniques","volume":"73 12","pages":"10884-10896"},"PeriodicalIF":4.5,"publicationDate":"2025-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11195965","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145778170","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}
Pub Date : 2025-10-07DOI: 10.1109/TMTT.2025.3615741
Youngjoo Lee;Juwon Kim;Byung-Wook Min
In this article, a Ka-band $4,times, 2$ switched beam array based on a 2-D Butler matrix for 5G mobile user equipment (UE) is presented. By using a 2-D Butler matrix, the feed lines between the IC and antennas are uniform, which is a crucial problem in integrated Butler matrices for 1-D arrays, as they require complex phase-matched routing on the PCB. The proposed $4times 2$ switched beam array is composed of a signal distribution IC (SDIC), a switched beamformer IC (SBIC) with $2times 2$ transmit/receive (TRX) channels, and stacked patch antennas. The proposed switched beam array can generate 22 beams using reconfigurable switch networks with dual-port excitation. In addition, it achieves an RX system noise figure (NF) of 4.4 dB and can support a TX saturated effective isotropic radiated power (EIRP) of at least 35 dBm for any 3-D spatial angle of ±44° in azimuth and ±43° in elevation directions. Although the proposed $4times 2$ switched beam array exhibits slight gain drops between adjacent beams, it enables simple control without any calibration. To the best of the authors’ knowledge, this is the first 2-D switched beam array with integrated ICs and antennas based on the Butler matrix in millimeter-wave bands.
{"title":"Ka-Band 4×2 Switched Beam Array Based on a 2-D Butler Matrix for 5G Mobile User Equipment","authors":"Youngjoo Lee;Juwon Kim;Byung-Wook Min","doi":"10.1109/TMTT.2025.3615741","DOIUrl":"https://doi.org/10.1109/TMTT.2025.3615741","url":null,"abstract":"In this article, a Ka-band <inline-formula> <tex-math>$4,times, 2$ </tex-math></inline-formula> switched beam array based on a 2-D Butler matrix for 5G mobile user equipment (UE) is presented. By using a 2-D Butler matrix, the feed lines between the IC and antennas are uniform, which is a crucial problem in integrated Butler matrices for 1-D arrays, as they require complex phase-matched routing on the PCB. The proposed <inline-formula> <tex-math>$4times 2$ </tex-math></inline-formula> switched beam array is composed of a signal distribution IC (SDIC), a switched beamformer IC (SBIC) with <inline-formula> <tex-math>$2times 2$ </tex-math></inline-formula> transmit/receive (TRX) channels, and stacked patch antennas. The proposed switched beam array can generate 22 beams using reconfigurable switch networks with dual-port excitation. In addition, it achieves an RX system noise figure (NF) of 4.4 dB and can support a TX saturated effective isotropic radiated power (EIRP) of at least 35 dBm for any 3-D spatial angle of ±44° in azimuth and ±43° in elevation directions. Although the proposed <inline-formula> <tex-math>$4times 2$ </tex-math></inline-formula> switched beam array exhibits slight gain drops between adjacent beams, it enables simple control without any calibration. To the best of the authors’ knowledge, this is the first 2-D switched beam array with integrated ICs and antennas based on the Butler matrix in millimeter-wave bands.","PeriodicalId":13272,"journal":{"name":"IEEE Transactions on Microwave Theory and Techniques","volume":"73 12","pages":"10827-10842"},"PeriodicalIF":4.5,"publicationDate":"2025-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145778182","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 hybrid transmitting and reflecting beyond-diagonal reconfigurable intelligent surface (BD-RIS) design is proposed. Operating in the same aperture, frequency band, and polarization, the proposed BD-RIS features independent beam steering control of its reflected and transmitted waves. In addition, it provides a hybrid mode with both reflected and transmitted waves, using tunable power splitting between beams. The BD-RIS comprises two phase reconfigurable antenna arrays interconnected by an array of tunable two-port power splitters. The two-port power splitter in each BD-RIS cell is built upon a varactor in parallel with a bias inductor, which exerts tunable impedance variations on transmission lines. Provided with variable reverse dc voltages, the two-port power splitter can control the power division ratio (PDR) of S11 over S21 from –26.2 to 23.5 dB, thus allowing tunable power splitting. Concurrently,each antenna is 2-bit phase reconfigurable with 200-MHz bandwidth at 2.4 GHz, so that each cell of BD-RIS can also achieve independent reflection and transmission phase control. To characterize and optimize the electromagnetic response of the proposed BD-RIS design, a Thévenin equivalent model and corresponding analytical method are provided. A BD-RIS with $4{times }4$ cells was also prototyped and tested. Experiments show that in reflection and transmission modes, the fabricated BD-RIS can realize beam steering in reflection and transmission space, respectively. It is also verified that when operating in hybrid mode, the BD-RIS enables independent beam steering of the reflected and transmitted waves. This work helps fill the gap between realizing practical hardware design and establishing an accurate physical model for the hybrid transmitting and reflecting BD-RIS, enabling hybrid transmitting and reflecting BD-RIS-assisted wireless communications.
{"title":"A Hybrid Transmitting and Reflecting Beyond-Diagonal Reconfigurable Intelligent Surface With Independent Beam Control and Power Splitting","authors":"Zhaoyang Ming;Shanpu Shen;Junhui Rao;Zan Li;Jichen Zhang;Chi-Yuk Chiu;Ross Murch","doi":"10.1109/TMTT.2025.3613155","DOIUrl":"https://doi.org/10.1109/TMTT.2025.3613155","url":null,"abstract":"A hybrid transmitting and reflecting beyond-diagonal reconfigurable intelligent surface (BD-RIS) design is proposed. Operating in the same aperture, frequency band, and polarization, the proposed BD-RIS features independent beam steering control of its reflected and transmitted waves. In addition, it provides a hybrid mode with both reflected and transmitted waves, using tunable power splitting between beams. The BD-RIS comprises two phase reconfigurable antenna arrays interconnected by an array of tunable two-port power splitters. The two-port power splitter in each BD-RIS cell is built upon a varactor in parallel with a bias inductor, which exerts tunable impedance variations on transmission lines. Provided with variable reverse dc voltages, the two-port power splitter can control the power division ratio (PDR) of S<sub>11</sub> over S<sub>21</sub> from –26.2 to 23.5 dB, thus allowing tunable power splitting. Concurrently,each antenna is 2-bit phase reconfigurable with 200-MHz bandwidth at 2.4 GHz, so that each cell of BD-RIS can also achieve independent reflection and transmission phase control. To characterize and optimize the electromagnetic response of the proposed BD-RIS design, a Thévenin equivalent model and corresponding analytical method are provided. A BD-RIS with <inline-formula> <tex-math>$4{times }4$ </tex-math></inline-formula> cells was also prototyped and tested. Experiments show that in reflection and transmission modes, the fabricated BD-RIS can realize beam steering in reflection and transmission space, respectively. It is also verified that when operating in hybrid mode, the BD-RIS enables independent beam steering of the reflected and transmitted waves. This work helps fill the gap between realizing practical hardware design and establishing an accurate physical model for the hybrid transmitting and reflecting BD-RIS, enabling hybrid transmitting and reflecting BD-RIS-assisted wireless communications.","PeriodicalId":13272,"journal":{"name":"IEEE Transactions on Microwave Theory and Techniques","volume":"73 12","pages":"10865-10883"},"PeriodicalIF":4.5,"publicationDate":"2025-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145778156","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 : 2025-10-06DOI: 10.1109/TMTT.2025.3613831
Yang Zhang;Kristof Vaesen;Giovanni Mangraviti;Kamil Yavuz Kapusuz;Sehoon Park;Miguel Glassee;Sam Lemey;Piet Wambacq;Giuseppe Gramegna
This article presents a 4-way transmitter (TX) array suitable for beamforming operation at D-band. The transmitter is implemented using zero-IF architecture with LO beamforming. The signal path comprises an I/Q baseband (BB) section, direct up-conversion, and a power amplifier chain, supporting a wideband operation from 118 to 147 GHz. A 5-stage 2-way power amplifier chain provides a saturation output power up to 11 dBm. The probing measurement results demonstrate up to 64 quadrature amplitude modulation (64QAM) [30 Gb/s at −25 dB rms-error vector magnitude (EVM)] and achieve a data rate of 56 Gb/s with a −17 dB rms-EVM at an output power of 3 dBm using 16QAM modulation. The LO chain contains a 14–16 GHz buffer, a cascade of two frequency triplers for LO generation at D-band using an external LO reference. A tunable matching network with 6-bit capacitor-band control is implemented in the buffer stage together with a polarity switch to achieve full range phase control. An efficient I/Q generation scheme is implemented by exploiting the last tripler before the I/Q mixer: two LC buffers after 1st tripler generates ±15° phase offset. This results into ±45° phase offset after the 2nd tripler. The benefits of our sub-harmonic I/Q generation are: 1) no I/Q hybrid operating in D-Band is needed; 2) the limited ±15° phase offset required allows an easy LC tuned buffer implementation with limited amplitude variation across phase range; and 3) this amplitude variation is removed by 2nd tripler and LO buffers that operate at saturation level. This LO beamforming scheme ensures a phase resolution of 0.1° in measurement. A single TX channel draws 232 mW from a 0.8 V supply and has an area of $1.17times 0.3$ mm2 in a 22 nm fully depleted silicon on insulator (FD-SOI) process. The 4-way beamformer IC has been flip-chip mounted on a low-cost 10-layer printed circuit board (PCB) and connected to a planar antenna array integrated at the backside of the PCB. The antennas are placed with 1.1 mm spacing and each antenna contains 4 aperture-coupled patch units to enhance the radiation pattern. The 4-way TX beamformer has been tested over-the-air (OTA) with a reference receiver achieving 24 Gb/s with −25 dB rms-EVM at 0.4 m distance using 5G NR waveforms.
{"title":"A 56 Gb/s Zero-IF D-Band Beamforming Transmitter in 22 nm FD-SOI","authors":"Yang Zhang;Kristof Vaesen;Giovanni Mangraviti;Kamil Yavuz Kapusuz;Sehoon Park;Miguel Glassee;Sam Lemey;Piet Wambacq;Giuseppe Gramegna","doi":"10.1109/TMTT.2025.3613831","DOIUrl":"https://doi.org/10.1109/TMTT.2025.3613831","url":null,"abstract":"This article presents a 4-way transmitter (TX) array suitable for beamforming operation at D-band. The transmitter is implemented using zero-IF architecture with LO beamforming. The signal path comprises an I/Q baseband (BB) section, direct up-conversion, and a power amplifier chain, supporting a wideband operation from 118 to 147 GHz. A 5-stage 2-way power amplifier chain provides a saturation output power up to 11 dBm. The probing measurement results demonstrate up to 64 quadrature amplitude modulation (64QAM) [30 Gb/s at −25 dB rms-error vector magnitude (EVM)] and achieve a data rate of 56 Gb/s with a −17 dB rms-EVM at an output power of 3 dBm using 16QAM modulation. The LO chain contains a 14–16 GHz buffer, a cascade of two frequency triplers for LO generation at D-band using an external LO reference. A tunable matching network with 6-bit capacitor-band control is implemented in the buffer stage together with a polarity switch to achieve full range phase control. An efficient I/Q generation scheme is implemented by exploiting the last tripler before the I/Q mixer: two <italic>LC</i> buffers after 1st tripler generates ±15° phase offset. This results into ±45° phase offset after the 2nd tripler. The benefits of our sub-harmonic I/Q generation are: 1) no I/Q hybrid operating in D-Band is needed; 2) the limited ±15° phase offset required allows an easy <italic>LC</i> tuned buffer implementation with limited amplitude variation across phase range; and 3) this amplitude variation is removed by 2nd tripler and LO buffers that operate at saturation level. This LO beamforming scheme ensures a phase resolution of 0.1° in measurement. A single TX channel draws 232 mW from a 0.8 V supply and has an area of <inline-formula> <tex-math>$1.17times 0.3$ </tex-math></inline-formula> mm<sup>2</sup> in a 22 nm fully depleted silicon on insulator (FD-SOI) process. The 4-way beamformer IC has been flip-chip mounted on a low-cost 10-layer printed circuit board (PCB) and connected to a planar antenna array integrated at the backside of the PCB. The antennas are placed with 1.1 mm spacing and each antenna contains 4 aperture-coupled patch units to enhance the radiation pattern. The 4-way TX beamformer has been tested over-the-air (OTA) with a reference receiver achieving 24 Gb/s with −25 dB rms-EVM at 0.4 m distance using 5G NR waveforms.","PeriodicalId":13272,"journal":{"name":"IEEE Transactions on Microwave Theory and Techniques","volume":"73 12","pages":"10904-10914"},"PeriodicalIF":4.5,"publicationDate":"2025-10-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145778172","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 : 2025-10-01DOI: 10.1109/TMTT.2025.3613357
Jian Hua Jiang;Li Gao;Xiu Yin Zhang
A 0.5–44-GHz ultrawideband (UWB) low-noise amplifier (LNA) with 3.6-dB maximum noise figure (NF) is presented in this article. The LNA employs three-stage amplification structure, with inverter-based amplifiers as the first and third stages, and a cascode amplifier as the second stage. In order to achieve both wideband impedance matching and noise matching simultaneously, a $G_{mathrm {m}}$ -boost resistive feedback structure and a multistage input matching configuration are utilized. To mitigate the effect of parasitic capacitances on gain in the millimeter-wave frequency band, several inductive gain-boost configurations are adopted. To verify the proposed design, the LNA is implemented in TSMC 28-nm CMOS process with 0.14-mm2 core size. The measured result shows that the proposed LNA achieves 3-dB bandwidth of 0.5–44 GHz with a maximum gain of 23 dB with 20.5-mW dc power consumption. The measured NF is 2.5–3.6 dB, and the minimum $K$ -factor is 3.7. The output 1-dB compression point (OP1 dB) is −4 to 0 dBm while the input third-order intercept point (IIP3) is −18.7 to −12 dBm. In summary, this design realized a comprehensive outstanding performance with a simple structure.
{"title":"A 0.5–44-GHz LNA With 23-dB Peak Gain and 3-dB Average NF in 28-nm CMOS Technology","authors":"Jian Hua Jiang;Li Gao;Xiu Yin Zhang","doi":"10.1109/TMTT.2025.3613357","DOIUrl":"https://doi.org/10.1109/TMTT.2025.3613357","url":null,"abstract":"A 0.5–44-GHz ultrawideband (UWB) low-noise amplifier (LNA) with 3.6-dB maximum noise figure (NF) is presented in this article. The LNA employs three-stage amplification structure, with inverter-based amplifiers as the first and third stages, and a cascode amplifier as the second stage. In order to achieve both wideband impedance matching and noise matching simultaneously, a <inline-formula> <tex-math>$G_{mathrm {m}}$ </tex-math></inline-formula>-boost resistive feedback structure and a multistage input matching configuration are utilized. To mitigate the effect of parasitic capacitances on gain in the millimeter-wave frequency band, several inductive gain-boost configurations are adopted. To verify the proposed design, the LNA is implemented in TSMC 28-nm CMOS process with 0.14-mm<sup>2</sup> core size. The measured result shows that the proposed LNA achieves 3-dB bandwidth of 0.5–44 GHz with a maximum gain of 23 dB with 20.5-mW dc power consumption. The measured NF is 2.5–3.6 dB, and the minimum <inline-formula> <tex-math>$K$ </tex-math></inline-formula>-factor is 3.7. The output 1-dB compression point (OP1 dB) is −4 to 0 dBm while the input third-order intercept point (IIP3) is −18.7 to −12 dBm. In summary, this design realized a comprehensive outstanding performance with a simple structure.","PeriodicalId":13272,"journal":{"name":"IEEE Transactions on Microwave Theory and Techniques","volume":"73 12","pages":"10855-10864"},"PeriodicalIF":4.5,"publicationDate":"2025-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145778165","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 : 2025-09-23DOI: 10.1109/TMTT.2025.3610037
Peng Chen;Xiaolong Wang;Lei Zhu;Geyu Lu
In this article, a novel wideband quasi-elliptic bandpass filter (BPF) is presented. The proposed structure comprised of two critical parts: the upper part circuit consisting of two cascaded quarter-wavelength coupled line (CL) structures and two shunted quarter-wavelength short-circuited stubs; the lower part circuit consisting of three types of coupled stub-loaded resonators, that is, coupled stub-loaded half-wavelength resonator (CSHR), coupled stub-loaded T-shaped resonator (CSTR), and coupled stub-loaded $Pi $ -shaped resonator (CS$Pi$ R). A general closed-form synthesis theory is then proposed to realize the quasi-elliptic bandpass filtering response, and the general quasi-elliptic function is given as $F$ ${}_{text {formula}} =$ cos($2phi + xi + 2gamma _{1}$ ) for CSHR and ${F} _{text {formula}} =$ cos($2phi + xi + 2gamma _{1} + 2gamma _{2}$ ) for CSTR and CS$Pi $ R. Distributed parameters are directly used to design wideband bandpass performance without any approximation and optimization procedure. Furthermore, the proposed synthesis theory could not only get equal-ripple performance in the passband but also newly realize equal-ripple response in the stopband. Finally, three prototype circuits were fabricated and measured, respectively. The simulation results are in good agreement with the measured results.
{"title":"Design of Wideband Bandpass Filters Based on Three Types of Coupled Stub-Loaded Resonators","authors":"Peng Chen;Xiaolong Wang;Lei Zhu;Geyu Lu","doi":"10.1109/TMTT.2025.3610037","DOIUrl":"https://doi.org/10.1109/TMTT.2025.3610037","url":null,"abstract":"In this article, a novel wideband quasi-elliptic bandpass filter (BPF) is presented. The proposed structure comprised of two critical parts: the upper part circuit consisting of two cascaded quarter-wavelength coupled line (CL) structures and two shunted quarter-wavelength short-circuited stubs; the lower part circuit consisting of three types of coupled stub-loaded resonators, that is, coupled stub-loaded half-wavelength resonator (CSHR), coupled stub-loaded T-shaped resonator (CSTR), and coupled stub-loaded <inline-formula> <tex-math>$Pi $ </tex-math></inline-formula>-shaped resonator (CS<inline-formula> <tex-math>$Pi$ </tex-math></inline-formula>R). A general closed-form synthesis theory is then proposed to realize the quasi-elliptic bandpass filtering response, and the general quasi-elliptic function is given as <inline-formula> <tex-math>$F$ </tex-math></inline-formula><inline-formula> <tex-math>${}_{text {formula}} =$ </tex-math></inline-formula> cos(<inline-formula> <tex-math>$2phi + xi + 2gamma _{1}$ </tex-math></inline-formula>) for CSHR and <inline-formula> <tex-math>${F} _{text {formula}} =$ </tex-math></inline-formula> cos(<inline-formula> <tex-math>$2phi + xi + 2gamma _{1} + 2gamma _{2}$ </tex-math></inline-formula>) for CSTR and CS<inline-formula> <tex-math>$Pi $ </tex-math></inline-formula>R. Distributed parameters are directly used to design wideband bandpass performance without any approximation and optimization procedure. Furthermore, the proposed synthesis theory could not only get equal-ripple performance in the passband but also newly realize equal-ripple response in the stopband. Finally, three prototype circuits were fabricated and measured, respectively. The simulation results are in good agreement with the measured results.","PeriodicalId":13272,"journal":{"name":"IEEE Transactions on Microwave Theory and Techniques","volume":"73 12","pages":"10617-10631"},"PeriodicalIF":4.5,"publicationDate":"2025-09-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145778242","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}
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