Pub Date : 2025-06-16DOI: 10.1109/LMWT.2025.3578128
Weiyuan Wang;Jingxiong Chen;Yuanxi Jiang;Xiao Ma;Yuanda Zheng;Hong Wang
We propose a self-aligned contact ledge structure to achieve the small ohmic contact resistance ($R_{text {c}}$ ) of GaN-based high electron mobility transistors (HEMTs) on Si for low-voltage RF applications. Without additional photolithography processes, the ledge structure is achieved by magnetron sputtering with good particle filling on the sidewall. Due to the good coverage of sputtered Ta, the self-aligned TaN contact ledge not only has a clear boundary after high-temperature annealing but also introduces an additional current path to reduce on-resistance (${R} _{text {on}}$ ), which is important for fabricating devices for low-voltage RF applications. Benefiting from the contact ledge structure and the low sheet resistance high Al component Al0.6Ga0.4N/GaN epitaxy, a low ${R} _{text {on}}$ of $1.12~Omega cdot $ mm is obtained and the peak transconductance increased by 13%. At 3.5 GHz and operating voltage 5 V, the power-added efficiency (PAE) is 67.0% and the output power density (${P} _{text {out}}$ ) is 0.75 W/mm. The PAE is 8.5% higher than that of noncontact ledge.
{"title":"AlGaN/GaN HEMTs on Si by Self-Aligned TaN Contact Ledge for Low-Voltage RF Applications","authors":"Weiyuan Wang;Jingxiong Chen;Yuanxi Jiang;Xiao Ma;Yuanda Zheng;Hong Wang","doi":"10.1109/LMWT.2025.3578128","DOIUrl":"https://doi.org/10.1109/LMWT.2025.3578128","url":null,"abstract":"We propose a self-aligned contact ledge structure to achieve the small ohmic contact resistance (<inline-formula> <tex-math>$R_{text {c}}$ </tex-math></inline-formula>) of GaN-based high electron mobility transistors (HEMTs) on Si for low-voltage RF applications. Without additional photolithography processes, the ledge structure is achieved by magnetron sputtering with good particle filling on the sidewall. Due to the good coverage of sputtered Ta, the self-aligned TaN contact ledge not only has a clear boundary after high-temperature annealing but also introduces an additional current path to reduce <sc>on</small>-resistance (<inline-formula> <tex-math>${R} _{text {on}}$ </tex-math></inline-formula>), which is important for fabricating devices for low-voltage RF applications. Benefiting from the contact ledge structure and the low sheet resistance high Al component Al<sub>0.6</sub>Ga<sub>0.4</sub>N/GaN epitaxy, a low <inline-formula> <tex-math>${R} _{text {on}}$ </tex-math></inline-formula> of <inline-formula> <tex-math>$1.12~Omega cdot $ </tex-math></inline-formula>mm is obtained and the peak transconductance increased by 13%. At 3.5 GHz and operating voltage 5 V, the power-added efficiency (PAE) is 67.0% and the output power density (<inline-formula> <tex-math>${P} _{text {out}}$ </tex-math></inline-formula>) is 0.75 W/mm. The PAE is 8.5% higher than that of noncontact ledge.","PeriodicalId":73297,"journal":{"name":"IEEE microwave and wireless technology letters","volume":"35 9","pages":"1388-1391"},"PeriodicalIF":3.4,"publicationDate":"2025-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145078675","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-06-16DOI: 10.1109/LMWT.2025.3576687
{"title":"IEEE Microwave and Wireless Technology Letters Information for Authors","authors":"","doi":"10.1109/LMWT.2025.3576687","DOIUrl":"https://doi.org/10.1109/LMWT.2025.3576687","url":null,"abstract":"","PeriodicalId":73297,"journal":{"name":"IEEE microwave and wireless technology letters","volume":"35 6","pages":"C3-C3"},"PeriodicalIF":0.0,"publicationDate":"2025-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11036842","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144299217","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-06-16DOI: 10.1109/LMWT.2025.3576706
{"title":"IEEE Microwave and Wireless Technology Letters Information for Authors","authors":"","doi":"10.1109/LMWT.2025.3576706","DOIUrl":"https://doi.org/10.1109/LMWT.2025.3576706","url":null,"abstract":"","PeriodicalId":73297,"journal":{"name":"IEEE microwave and wireless technology letters","volume":"35 6","pages":"C3-C3"},"PeriodicalIF":0.0,"publicationDate":"2025-06-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11036846","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144299069","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-06-11DOI: 10.1109/LMWT.2025.3573897
Joel Mesas;Jordi Verdú;Pedro de Paco
This work extends a matrix-based numerical methodology to cover fully canonical generalized Chevyshev (GC) transfer functions by reconfiguring canonical filter topologies into dangling inline structures, with a direct impact on the consideration of ladder circuit filters. The transformation matrix that maps a canonical matrix to the dangling inline is defined in such a way that, within a mathematical matrix completion framework, it can nullify the source-load coupling, modify the source and load reactances to accommodate the phase at the first and last extracted-pole sections of the network, and capture the response information in a different size matrix.
{"title":"Synthesis of In-Line Fully Canonical Filters by Solving a Matrix Completion Problem Under AW Ladder Constraints","authors":"Joel Mesas;Jordi Verdú;Pedro de Paco","doi":"10.1109/LMWT.2025.3573897","DOIUrl":"https://doi.org/10.1109/LMWT.2025.3573897","url":null,"abstract":"This work extends a matrix-based numerical methodology to cover fully canonical generalized Chevyshev (GC) transfer functions by reconfiguring canonical filter topologies into dangling inline structures, with a direct impact on the consideration of ladder circuit filters. The transformation matrix that maps a canonical matrix to the dangling inline is defined in such a way that, within a mathematical matrix completion framework, it can nullify the source-load coupling, modify the source and load reactances to accommodate the phase at the first and last extracted-pole sections of the network, and capture the response information in a different size matrix.","PeriodicalId":73297,"journal":{"name":"IEEE microwave and wireless technology letters","volume":"35 9","pages":"1272-1275"},"PeriodicalIF":3.4,"publicationDate":"2025-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11030593","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145078593","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-06-11DOI: 10.1109/LMWT.2025.3575467
Ze Du;Zhi-Yu Duan;Ke Zhan;Zhen-Hua Wu;Ji-Sheng Chen;Hu Li;Ming-Zhou Zhan
In this letter, a large chip-width terahertz monolithic integrated circuits (TMICs) packaging solution at terahertz (THz) frequencies is presented. The proposed electromagnetic bandgap (EBG) structure in this design can effectively suppress various interference modes generated when the slit width increases. The mode conversion and interconnection between coplanar waveguide with ground (CPWG) and waveguide are realized using integrated on-chip dipole antenna transition model. To verify the proposed solution, a packaging structure accommodating a chip width of 3760 $mu $ m and an on-chip integrated dipole antenna transition model were designed and fabricated. The test results show that in the frequency range of 214–242 GHz, the return loss is better than 9 dB and the insertion loss is better than 4 dB, the de-embedded average loss is less than 1 dB.
{"title":"A Large Chip-Width TMICs Packaging Solution for THz Applications","authors":"Ze Du;Zhi-Yu Duan;Ke Zhan;Zhen-Hua Wu;Ji-Sheng Chen;Hu Li;Ming-Zhou Zhan","doi":"10.1109/LMWT.2025.3575467","DOIUrl":"https://doi.org/10.1109/LMWT.2025.3575467","url":null,"abstract":"In this letter, a large chip-width terahertz monolithic integrated circuits (TMICs) packaging solution at terahertz (THz) frequencies is presented. The proposed electromagnetic bandgap (EBG) structure in this design can effectively suppress various interference modes generated when the slit width increases. The mode conversion and interconnection between coplanar waveguide with ground (CPWG) and waveguide are realized using integrated on-chip dipole antenna transition model. To verify the proposed solution, a packaging structure accommodating a chip width of 3760 <inline-formula> <tex-math>$mu $ </tex-math></inline-formula>m and an on-chip integrated dipole antenna transition model were designed and fabricated. The test results show that in the frequency range of 214–242 GHz, the return loss is better than 9 dB and the insertion loss is better than 4 dB, the de-embedded average loss is less than 1 dB.","PeriodicalId":73297,"journal":{"name":"IEEE microwave and wireless technology letters","volume":"35 9","pages":"1440-1443"},"PeriodicalIF":3.4,"publicationDate":"2025-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145078633","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-06-11DOI: 10.1109/LMWT.2025.3575160
Xingyue Guo;He Ming Yao;Yuan’an Liu;Michael Ng;Shiji Song
This article proposes a novel deep learning (DL) approach to realize quantitative real-time microwave imaging (MWI) in the extremely broad frequency band. The proposed DL approach is based on the deep convolutional V-net structure, which employs the residual block and deep convolutional operation to improve its generality and performance. To integrate the physics-based prior to DL model, the inverse-forward closed-loop training framework is introduced to compute the training loss, which comprises two fundamental components: 1) the inverse process for computing data-driven loss, which directly quantifies the dissimilarity between the predictions of our proposed V-net and the actual target contrasts and 2) the forward process for computing physics-driven loss, which evaluates the distinctions between the input EM scattered field and the computed EM scattered field derived from the prediction of V-net. Consequently, the proposed DL method can work with excellent accuracy even for heterogeneous and high-contrast targets, only requiring the single-frequency far-field-measured EM scattered field at the arbitrary frequency in the extremely broad frequency band. Moreover, the proposed DL method can present satisfactory robust on the extremely broad frequency band and provide nearly the same excellent inversion performance on totally different frequencies for one target scatterer. Numerical benchmarks illustrate the feasibility of this proposed DL method.
{"title":"Deep Learning Approach for Microwave Imaging in Broad Frequency Band Based on Physics-Driven Loss and Deep Convolutional V-Net Structure","authors":"Xingyue Guo;He Ming Yao;Yuan’an Liu;Michael Ng;Shiji Song","doi":"10.1109/LMWT.2025.3575160","DOIUrl":"https://doi.org/10.1109/LMWT.2025.3575160","url":null,"abstract":"This article proposes a novel deep learning (DL) approach to realize quantitative real-time microwave imaging (MWI) in the extremely broad frequency band. The proposed DL approach is based on the deep convolutional V-net structure, which employs the residual block and deep convolutional operation to improve its generality and performance. To integrate the physics-based prior to DL model, the inverse-forward closed-loop training framework is introduced to compute the training loss, which comprises two fundamental components: 1) the inverse process for computing data-driven loss, which directly quantifies the dissimilarity between the predictions of our proposed V-net and the actual target contrasts and 2) the forward process for computing physics-driven loss, which evaluates the distinctions between the input EM scattered field and the computed EM scattered field derived from the prediction of V-net. Consequently, the proposed DL method can work with excellent accuracy even for heterogeneous and high-contrast targets, only requiring the single-frequency far-field-measured EM scattered field at the arbitrary frequency in the extremely broad frequency band. Moreover, the proposed DL method can present satisfactory robust on the extremely broad frequency band and provide nearly the same excellent inversion performance on totally different frequencies for one target scatterer. Numerical benchmarks illustrate the feasibility of this proposed DL method.","PeriodicalId":73297,"journal":{"name":"IEEE microwave and wireless technology letters","volume":"35 9","pages":"1264-1267"},"PeriodicalIF":3.4,"publicationDate":"2025-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145078567","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-06-11DOI: 10.1109/LMWT.2025.3574501
Mehmet Emin Arslan;Ulrich Nordmeyer;Niels Neumann
Reconfigurable intelligent surfaces (RISs) play a significant role in 6G wireless communications by dynamically controlling the reflections of electromagnetic (EM) waves. In this work, p-i-n diodes are used to achieve the necessary phase shifts in the 1-bit RIS unit cells. In order to characterize these diodes over a frequency range from 10 to 30 GHz, de-embedding structures are carefully designed and analytically modeled. By de-embedding the test structure and matching the model parameters with empirical measurements, the behavior of p-i-n diodes within RIS unit cells is accurately determined. The developed characterization method can be easily adapted to other RF measurement tasks involving complex designs at high frequencies, thus broadening its applicability.
{"title":"General Method for Characterizing Switchable Elements for RIS Using De-Embedding Structures","authors":"Mehmet Emin Arslan;Ulrich Nordmeyer;Niels Neumann","doi":"10.1109/LMWT.2025.3574501","DOIUrl":"https://doi.org/10.1109/LMWT.2025.3574501","url":null,"abstract":"Reconfigurable intelligent surfaces (RISs) play a significant role in 6G wireless communications by dynamically controlling the reflections of electromagnetic (EM) waves. In this work, p-i-n diodes are used to achieve the necessary phase shifts in the 1-bit RIS unit cells. In order to characterize these diodes over a frequency range from 10 to 30 GHz, de-embedding structures are carefully designed and analytically modeled. By de-embedding the test structure and matching the model parameters with empirical measurements, the behavior of p-i-n diodes within RIS unit cells is accurately determined. The developed characterization method can be easily adapted to other RF measurement tasks involving complex designs at high frequencies, thus broadening its applicability.","PeriodicalId":73297,"journal":{"name":"IEEE microwave and wireless technology letters","volume":"35 9","pages":"1444-1447"},"PeriodicalIF":3.4,"publicationDate":"2025-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145078651","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-06-10DOI: 10.1109/LMWT.2025.3575715
Fachun He;Shuang Liu;Longfang Ye;Huali Zhu;Dan Lei;Jun Yan
We propose a novel F-fold spoof surface plasmon polaritons (SSPPs) unit with independently tunable high-order rejection bands. The dispersion characteristics of the proposed F-fold SSPPs are analyzed. The results show that the cutoff frequencies of Modes 2 and 3 can be precisely adjusted through structural parameters, enabling independent control of the stopband position formed by these two modes, without affecting the fundamental mode (Mode 0) or Mode 1. Therefore, the passband number, bandwidth, and stopband width can be flexibly manipulated for the design of multiple passband filters. For verification, a tri-passband, quad-passband filter, and wide stopband filter are designed, fabricated, and measured. The wide stopband filter achieves a 547% increase in the stopband width compared to the tri-passband filter. Good agreement between the simulations and measurements confirms the feasibility of the proposed structure and design method.
{"title":"Multipassband and Wide-Stopband Filters via Independent Tuning of High-Order SSPP Modes","authors":"Fachun He;Shuang Liu;Longfang Ye;Huali Zhu;Dan Lei;Jun Yan","doi":"10.1109/LMWT.2025.3575715","DOIUrl":"https://doi.org/10.1109/LMWT.2025.3575715","url":null,"abstract":"We propose a novel <italic>F</i>-fold spoof surface plasmon polaritons (SSPPs) unit with independently tunable high-order rejection bands. The dispersion characteristics of the proposed <italic>F</i>-fold SSPPs are analyzed. The results show that the cutoff frequencies of Modes 2 and 3 can be precisely adjusted through structural parameters, enabling independent control of the stopband position formed by these two modes, without affecting the fundamental mode (Mode 0) or Mode 1. Therefore, the passband number, bandwidth, and stopband width can be flexibly manipulated for the design of multiple passband filters. For verification, a tri-passband, quad-passband filter, and wide stopband filter are designed, fabricated, and measured. The wide stopband filter achieves a 547% increase in the stopband width compared to the tri-passband filter. Good agreement between the simulations and measurements confirms the feasibility of the proposed structure and design method.","PeriodicalId":73297,"journal":{"name":"IEEE microwave and wireless technology letters","volume":"35 9","pages":"1288-1291"},"PeriodicalIF":3.4,"publicationDate":"2025-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145078697","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-06-09DOI: 10.1109/LMWT.2025.3565314
Li Qian;Liyu Zhu;Jun Xu;Weiheng Chen;Zhiqiang Yu;Jianyi Zhou;Wei Hong
This letter proposes manufacture-friendly millimeter-wave (mm-Wave) bandpass filter (BPF) based on double-folded substrate integrated waveguide (DFSIW) cavities. Using an incompletely folded structure and parallel rectangular slots as coupling structures, the BPF achieves reduced insertion loss (IL) and enhanced robustness against processing errors. Furthermore, the compact space between adjacent folded slots was transformed into a cross-coupling structure, which significantly improves frequency selectivity without introducing additional radiation loss. In addition, high-quality (Q) factor layer stacking is implemented to further minimize IL. A Ka-band filter prototype based on the multilayer printed circuit board (PCB) is fabricated and measured to confirm the feasibility.
{"title":"Manufacture-Friendly Millimeter-Wave Filter Based on Double-Folded SIW Resonators","authors":"Li Qian;Liyu Zhu;Jun Xu;Weiheng Chen;Zhiqiang Yu;Jianyi Zhou;Wei Hong","doi":"10.1109/LMWT.2025.3565314","DOIUrl":"https://doi.org/10.1109/LMWT.2025.3565314","url":null,"abstract":"This letter proposes manufacture-friendly millimeter-wave (mm-Wave) bandpass filter (BPF) based on double-folded substrate integrated waveguide (DFSIW) cavities. Using an incompletely folded structure and parallel rectangular slots as coupling structures, the BPF achieves reduced insertion loss (IL) and enhanced robustness against processing errors. Furthermore, the compact space between adjacent folded slots was transformed into a cross-coupling structure, which significantly improves frequency selectivity without introducing additional radiation loss. In addition, high-quality (<italic>Q</i>) factor layer stacking is implemented to further minimize IL. A <italic>Ka</i>-band filter prototype based on the multilayer printed circuit board (PCB) is fabricated and measured to confirm the feasibility.","PeriodicalId":73297,"journal":{"name":"IEEE microwave and wireless technology letters","volume":"35 9","pages":"1296-1299"},"PeriodicalIF":3.4,"publicationDate":"2025-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145078623","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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