IEEE Transactions on Microwave Theory and Techniques最新文献

{"title":"A Highly Compact Metasurface Absorber Incorporating Piezoelectrics for Hybrid RF–Vibration Energy Harvesting","authors":"Mahsa Zabetiakmal;Güneş Karabulut Kurt;Elham Baladi","doi":"10.1109/TMTT.2026.3652088","DOIUrl":"https://doi.org/10.1109/TMTT.2026.3652088","url":null,"abstract":"This work presents an innovative compact metasurface perfect absorber (MPA) for hybrid energy harvesting (EH), marking a substantial breakthrough in the advancement of sustainable power sources. The unique design integrates two distinct EH techniques [radio frequency (RF) and vibration] through the use of a piezoelectric material as the substrate for the metasurface. The metasurface elements additionally serve as electrodes to capture the voltage generated from vibrations, with the entire structure functioning as a cantilever resonator, a widely recognized mechanical resonator used in vibration harvesting applications. The interdigitated geometry of the metasurface elements and the incorporation of a high-dielectric-constant piezoelectric material allow for the creation of a miniaturized metasurface element, measuring only <inline-formula> <tex-math>$0.12 lambda $ </tex-math></inline-formula> at 2.4 GHz. The design achieves an absorption efficiency exceeding 96%, while ensuring robust performance and insensitivity to changes in polarization and incident angles. Experimental validations demonstrate that the proposed hybrid harvester operates efficiently under both microwave and mechanical excitations, providing a reliable and sustainable power solution. This novelty in design and approach establishes the proposed hybrid energy harvester as a sustainable power source with significant potential impact.","PeriodicalId":13272,"journal":{"name":"IEEE Transactions on Microwave Theory and Techniques","volume":"74 4","pages":"3918-3932"},"PeriodicalIF":4.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147665258","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}

{"title":"2025 Reviewer List","authors":"Almudena Suarez;Changzhi Li","doi":"10.1109/TMTT.2026.3675311","DOIUrl":"https://doi.org/10.1109/TMTT.2026.3675311","url":null,"abstract":"","PeriodicalId":13272,"journal":{"name":"IEEE Transactions on Microwave Theory and Techniques","volume":"74 4","pages":"3945-3957"},"PeriodicalIF":4.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11480774","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147665421","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}

{"title":"2-D Flexible Phased Array Shape Reconstruction","authors":"Oren S. Mizrahi;Ali Hajimiri","doi":"10.1109/TMTT.2025.3649052","DOIUrl":"https://doi.org/10.1109/TMTT.2025.3649052","url":null,"abstract":"Flexible phased arrays can address new applications and provide new capabilities in communications, radar, sensing, and wireless power transfer due to their novel form factor, which enables rapid deployment, conformity, and mass and size advantages. However, the variable position of their elements makes them vulnerable to the deleterious effects of incoherence. This problem can be addressed by reconstructing the shape of the array and compensating for the change in the position of the radiator at the system level. This article presents a method for reconstructing the shape of a 2-D flexible phased array using only measurements of mutual coupling between the array elements. The method consists of an optimization loop: predicting the coupling for a given shape, comparing the prediction to measurement, and iterating through shape perturbations using the Levenberg–Marquardt algorithm. Shape reconstruction is demonstrated with a <inline-formula> <tex-math>$approx 0.08~lambda $ </tex-math></inline-formula> mean position error across a wide variety of shape configurations on a passive <inline-formula> <tex-math>$8times 8$ </tex-math></inline-formula> flexible patch antenna array operating at <inline-formula> <tex-math>$approx 5$ </tex-math></inline-formula> GHz.","PeriodicalId":13272,"journal":{"name":"IEEE Transactions on Microwave Theory and Techniques","volume":"74 4","pages":"3870-3888"},"PeriodicalIF":4.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147665418","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}

{"title":"Analysis and Experiment of a Low-Cost Multipanel Reconfigurable Intelligent Surface System for Signal Enhancement at mm-wave","authors":"Peyman Aghabeyki;Peng Mei;Zhinong Ying;Gert Frølund Pedersen;Shuai Zhang","doi":"10.1109/TMTT.2026.3653631","DOIUrl":"https://doi.org/10.1109/TMTT.2026.3653631","url":null,"abstract":"This study presents a novel approach to enhance the power level at millimeter waves (mm-waves) with very low cost. Considering an mm-wave base station (BS) in a fixed location and the user equipment (UE) in the far-field (FF) region, a plane wave with a known direction of propagation reaches a specific region. A very large, predesigned fixed focal spot passive surface (S1) is designed and installed within the viewing angle of the plane wave to reflect and focus it in the near-field (NF) region on another wall. A small reconfigurable intelligent surface (RIS) device is installed on the other wall to be illuminated by the focused beam, and the RIS steers the beam dynamically inside the desired region toward the UE. By using this scheme, a large amount of power can be focused on the UEs to enhance the signal level. The components are modeled with full-wave electromagnetic simulation, and the best approach to design the mm-wave system is discussed. A prototype was fabricated and measured at 26 GHz to demonstrate the 2-D beam steering. The large passive fixed-beam surface is a single-layer printed circuit board (PCB) with <inline-formula> <tex-math>$20times 20$ </tex-math></inline-formula> cm, and the RIS is <inline-formula> <tex-math>$7times 7$ </tex-math></inline-formula> cm (<inline-formula> <tex-math>$14times 14$ </tex-math></inline-formula> elements). For demonstration, 1-bit mechanical tuning elements are used for simplicity. Measurement results show <inline-formula> <tex-math>$approx pm 50^{circ }$ </tex-math></inline-formula> of 2-D beam steering with around 10% gain bandwidth. The radiation characteristics of both surfaces are analyzed, and an expression for received power under the general condition is obtained. The entire system can be implemented at a very low cost due to its simple PCB design and small-scale RIS. Moreover, due to the large passive surface and small RIS, the power consumption can be significantly reduced compared to conventional RIS.","PeriodicalId":13272,"journal":{"name":"IEEE Transactions on Microwave Theory and Techniques","volume":"74 4","pages":"3889-3903"},"PeriodicalIF":4.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147665415","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}

{"title":"A Double L-Shaped 4-D MIMO Radar Array With Optimal Subspace-Based Angular Resolution","authors":"Yuchen Li;Jiayu Zhang;Changzhan Gu","doi":"10.1109/TMTT.2025.3649652","DOIUrl":"https://doi.org/10.1109/TMTT.2025.3649652","url":null,"abstract":"This article presents an optimal angular resolution array design method for 4-D multiple-input and multiple-output (MIMO) radar systems, leveraging subspace-based direction-of-arrival (DOA) estimation algorithms. In MIMO radar, the array configuration is a key factor determining angular resolution. Among various topologies, the L-shaped structure provides a favorable balance between aperture use and noise robustness. Specifically, for a uniform planar array, the angular resolution improves with larger apertures along two orthogonal axes, while the L-shaped configuration achieves the best angular antinoise performance under the same aperture size. To maximize the virtual L-shaped aperture, both the transmit and receive arrays are configured in identical L-shaped orientations, forming a virtual array that preserves the optimal structure. Detailed modeling of angular resolution for 1-D linear and 2-D planar arrays is conducted, introducing an angular resolution discriminant (ARD) to evaluate the angular performance of different configurations. The impact of noise on array signals is explored, along with the concept of redundant elements. By combining the ARD with the properties of redundant elements, the double L-shaped array design is shown to achieve optimal angular resolution in both the theta and phi planes using subspace-based methods. Following the proposed approach, a 4T8R MIMO radar prototype is designed and fabricated, demonstrating angular resolutions of 8.4° and 6.1° in the theta and phi planes, respectively. Several indoor multitarget detection experiments highlight the proposed technique’s potential for indoor tracking and multipeople vital sign monitoring applications. The proposed technique is well-suited for super-resolution subspace-based angle estimation algorithms, providing a balance between simplicity and low computational complexity. This array design approach provides a solid theoretical foundation for future 4-D millimeter-wave radar applications.","PeriodicalId":13272,"journal":{"name":"IEEE Transactions on Microwave Theory and Techniques","volume":"74 4","pages":"3933-3944"},"PeriodicalIF":4.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147665397","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}

{"title":"Frequency Agile Analog Kramers–Kronig Receiver in Silicon","authors":"Shiyuan Yu;Yutian Zhao;Letian Li;Xiepeng Chen;Yuxiang Han;Suresh Venkatesh;Xuyang Lu","doi":"10.1109/TMTT.2026.3652833","DOIUrl":"https://doi.org/10.1109/TMTT.2026.3652833","url":null,"abstract":"Direct detection (DD) receivers (RXs) offer low power and complexity for high-frequency wireless communication but suffer from signal-to-signal beat interference (SSBI), which degrades signal quality. Kramers–Kronig (KK)-based RXs mitigate SSBI by recovering phase from amplitude, but conventional implementations are hindered by heavy reliance on digital signal processing (DSP), non-real-time operation, and spectrum broadening, limiting hardware integration. This article introduces an innovative fully analog detection scheme for a CMOS integrated circuit (IC) KK RX. Our solution employs Taylor-series expansion for nonlinear circuits, a poly-phase filter (PPF) for Hilbert transform, and an entirely analog RF signal chain. These techniques enable a low-power, local oscillator (LO)-free coherent DD RX capable of real-time signal reception without spectrum broadening, and they support coherent reception across various carrier frequencies. We demonstrate this technique with a W-band KK-based RX in a 65-nm CMOS process, achieving a 200-Mb/s modulation rate. The design shows a 1.8-dB error vector magnitude (EVM) improvement, 82.89% bit-error-rate (BER) improvement, and 0.8-dB carrier-to-signal power ratio (CSPR) reduction compared with conventional methods. The RF frontend exhibits 3.4-kV/W responsivity and 14.2-dB noise figure at 90 GHz, with the core module consuming 29 mW of dc power and occupying 0.132 mm2. These results highlight the potential for enhanced energy efficiency and local oscillator-free, coherent reception in high-frequency communication.","PeriodicalId":13272,"journal":{"name":"IEEE Transactions on Microwave Theory and Techniques","volume":"74 4","pages":"3904-3917"},"PeriodicalIF":4.5,"publicationDate":"2026-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147665376","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}

{"title":"High-Power Dual-Band RF Rectifier With Multifocus GaN Techniques for WPT Applications","authors":"Xiaochen Yu;Haoran Wang;Ya-Xun Lin;Xiantao Yang;Yeke Liu;Shawn S. H. Hsu;Ta-Jen Yen;Ivona Z. Mitrovic;Yi Huang;Jiafeng Zhou;Yejun He;Chaoyun Song","doi":"10.1109/TMTT.2025.3637595","DOIUrl":"https://doi.org/10.1109/TMTT.2025.3637595","url":null,"abstract":"This article presents a spatially adaptive dual-band rectifier leveraging multifocus gallium nitride (GaN) techniques, specifically designed for high-power wireless power transfer (WPT) applications. To address the challenges of watt-level power handling, frequency-specific performance optimization, and high RF-to-dc conversion efficiency, two custom-fabricated GaN Schottky barrier diodes (SBDs) are codesigned with dedicated matching networks for their respective frequency bands. For low-frequency operation at 0.875 GHz, a quasi-vertical GaN-on-Si SBD is developed, achieving a high breakdown voltage of 145 V and a near-ideal ideality factor of 1.03, ensuring both watt-level robustness and high efficiency under low-power excitation, which is particularly critical for sub-GHz IoT scenarios. For high-frequency operation at 5.8 GHz, a GaN-on-SiC SBD with a Y-shaped anode features a breakdown voltage of 205 V and an ultralow junction capacitance of 0.19 pF, extending the cutoff frequency while maintaining excellent power stability. A compact band-optimized matching network incorporating short-circuited stubs enables efficient impedance transformation across both frequency bands. The proposed rectifier achieves a peak RF-to-dc efficiency exceeding 65% at input powers above 6.3 W across both bands. This work addresses the unmet need for rectifiers capable of watt-level RF-to-dc conversion using frequency-specific GaN SBDs. The key contribution lies in the device-circuit codesign of high-power GaN rectifiers, which has not been previously demonstrated.","PeriodicalId":13272,"journal":{"name":"IEEE Transactions on Microwave Theory and Techniques","volume":"74 3","pages":"3006-3019"},"PeriodicalIF":4.5,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147557610","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}

{"title":"Corrections to “45°/90° Broadband Phase Shifter MMICs Using Switchable Electric–Magnetic Coupling Path Architecture”","authors":"Na Ji;Guangxu Shen;Dingyuan Zeng;Wenjie Feng;Wenquan Che","doi":"10.1109/TMTT.2026.3655127","DOIUrl":"https://doi.org/10.1109/TMTT.2026.3655127","url":null,"abstract":"In the above article [1], there were errors on pages 2 and 8. They are explained below, and the corrections are provided.","PeriodicalId":13272,"journal":{"name":"IEEE Transactions on Microwave Theory and Techniques","volume":"74 5","pages":"4879-4879"},"PeriodicalIF":4.5,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11513600","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147828850","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}

{"title":"Sustainable, 3D-Printed Liquid Metal Reprogrammable Resonator Toward Fully Circular RF Sensing and Identification","authors":"Xiaochuan Fang;Mahmoud Wagih","doi":"10.1109/TMTT.2025.3638629","DOIUrl":"https://doi.org/10.1109/TMTT.2025.3638629","url":null,"abstract":"Microwave resonators are widely used for spectral RF sensing and identification, but their sustainability and circularity are hindered by a lack of reconfigurability. Herein, we present the first sustainable, fully recyclable, and reprogrammable microwave sensing resonator, based on liquid metal and additively manufactured, modular multilayered fluidic channels. The proposed structure leverages a capacitively coupled 3D-printed liquid resonator layer over a microstrip transmission line layer, with additional sensing layers integrated vertically above the recodable identification liquid Galinstan resonators. The resonators’ layer and its subsequent sensing layers are printed using semi-transparent stereolithography (SLA) resin. Five identification bits are implemented using refillable resonators, allowing the resonator to be recoded by filling or emptying liquid metal within different channels. Circularity is demonstrated over 12 cycles, with the liquid metal recovered with under 1.5% waste at the end of life. The encoding and sensing notch filters are implemented using five bandstop resonators at 2–7 GHz. The resonator is demonstrated in two exemplary sensing applications, including real-permittivity-based liquid detection and touch sensing, showing the potential uses in human–RFID interaction.","PeriodicalId":13272,"journal":{"name":"IEEE Transactions on Microwave Theory and Techniques","volume":"74 3","pages":"3020-3029"},"PeriodicalIF":4.5,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147557754","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}

{"title":"A U6G Frequency-Division Multiplexing Fully Connected MIMO Transmitter Based on the LO Phase Shifting Technique","authors":"Hongji Fan;Yiqiu Liang;Weiheng Chen;Zhaoyi Wang;Zhiqiang Yu;Jianyi Zhou;Wei Hong","doi":"10.1109/TMTT.2025.3643513","DOIUrl":"https://doi.org/10.1109/TMTT.2025.3643513","url":null,"abstract":"In this article, a local-oscillator-phase-shifting (LOPS)-based frequency-division multiplexing MIMO (FD-MIMO) architecture is proposed. It can achieve the same multibeam performance as the fully connected system without the complex crossover connection network. Different from traditional superheterodyne systems, multiple data streams are allocated to different intermediate frequency (IF) bands, and the LO is a multitone signal instead of a single-tone signal. The multitone LO phase shifting is used to realize flexible multibeam forming. To validate the feasibility of the proposed scheme, an eight-element, four-stream U6G FD-multi-input multi-output (MIMO) transmitter is designed with a 400-MHz signal bandwidth. In circuit implementations, the FD-MIMO framework is perfectly integrated with the traditional fully connected scheme to further improve the communication capacity. Finally, during indoor measurements, the MIMO system achieves a 9.6-Gb/s data rate with 64-QAM modulation.","PeriodicalId":13272,"journal":{"name":"IEEE Transactions on Microwave Theory and Techniques","volume":"74 3","pages":"2991-3005"},"PeriodicalIF":4.5,"publicationDate":"2026-03-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147557767","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}