Pub Date : 2025-08-18DOI: 10.1109/LMWT.2025.3597414
Jeong-Hun Park;Seon-Hwa Yun;Moon-Que Lee
In this letter, a new electromagnetic field (EMF) exposure application adopting the chamber of a coaxial line at 433 MHz designed for eight Alzheimer’s transgenic mice. Its structure consists of three types of coaxial lines: the first is standard coaxial line (e.g., N-type) for RF signal input or dummy load termination; the second has a characteristic impedance of $50~Omega $ for mode-matching between both standard coaxial line and chamber; and the third is used for the EMF exposure chamber. The mode-matching coaxial line features its dielectric diameter comparable to that of the chamber coaxial line. The EMF exposure chamber based on the coaxial line has the advantages of the wide impedance bandwidth and no external EMF emissions. The measured return loss for the system with eight phantoms was demonstrated as 20.9 dB at 433 MHz with a wide bandwidth. The estimated SAR at the target region was achieved as 0.051 W/kg/Winc.
{"title":"EMF Exposure Application Using the Chamber of a Coaxial Line for 433-MHz ISM Band","authors":"Jeong-Hun Park;Seon-Hwa Yun;Moon-Que Lee","doi":"10.1109/LMWT.2025.3597414","DOIUrl":"https://doi.org/10.1109/LMWT.2025.3597414","url":null,"abstract":"In this letter, a new electromagnetic field (EMF) exposure application adopting the chamber of a coaxial line at 433 MHz designed for eight Alzheimer’s transgenic mice. Its structure consists of three types of coaxial lines: the first is standard coaxial line (e.g., N-type) for RF signal input or dummy load termination; the second has a characteristic impedance of <inline-formula> <tex-math>$50~Omega $ </tex-math></inline-formula> for mode-matching between both standard coaxial line and chamber; and the third is used for the EMF exposure chamber. The mode-matching coaxial line features its dielectric diameter comparable to that of the chamber coaxial line. The EMF exposure chamber based on the coaxial line has the advantages of the wide impedance bandwidth and no external EMF emissions. The measured return loss for the system with eight phantoms was demonstrated as 20.9 dB at 433 MHz with a wide bandwidth. The estimated SAR at the target region was achieved as 0.051 W/kg/W<sub>inc</sub>.","PeriodicalId":73297,"journal":{"name":"IEEE microwave and wireless technology letters","volume":"35 12","pages":"2093-2096"},"PeriodicalIF":3.4,"publicationDate":"2025-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145766182","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 : 2025-08-05DOI: 10.1109/LMWT.2025.3591716
Xu Zhu;Shaoyue Wang;Da He;Liping Yan;Jianan Hu;Changjun Liu
Conventional microwave heating techniques are limited due to inherent thermal point residency effects and inadequate control over the heating process. A novel method is proposed to enhance microwave heating uniformity using the injection-pulling technique. In this method, the injection-pulling technique is used to achieve simultaneous modulation of both the output phase and frequency of the magnetron, thereby extending the locking bandwidth of the injection-locking technique. The output characteristics of the injection-pulled magnetron were validated through numerical calculations and experiments. Microwave heating experiments were conducted under both a five-cup water load and an absorbent paper load. Compared with conventional injection-locking frequency sweeping, the proposed method not only expands the sweeping bandwidth from 8 to 18 MHz but also further improves heating uniformity, offering more options for magnetron applications in microwave heating.
{"title":"Study on Improving Microwave Heating Uniformity Based on Phase–Frequency Simultaneous Modulation Technique","authors":"Xu Zhu;Shaoyue Wang;Da He;Liping Yan;Jianan Hu;Changjun Liu","doi":"10.1109/LMWT.2025.3591716","DOIUrl":"https://doi.org/10.1109/LMWT.2025.3591716","url":null,"abstract":"Conventional microwave heating techniques are limited due to inherent thermal point residency effects and inadequate control over the heating process. A novel method is proposed to enhance microwave heating uniformity using the injection-pulling technique. In this method, the injection-pulling technique is used to achieve simultaneous modulation of both the output phase and frequency of the magnetron, thereby extending the locking bandwidth of the injection-locking technique. The output characteristics of the injection-pulled magnetron were validated through numerical calculations and experiments. Microwave heating experiments were conducted under both a five-cup water load and an absorbent paper load. Compared with conventional injection-locking frequency sweeping, the proposed method not only expands the sweeping bandwidth from 8 to 18 MHz but also further improves heating uniformity, offering more options for magnetron applications in microwave heating.","PeriodicalId":73297,"journal":{"name":"IEEE microwave and wireless technology letters","volume":"35 11","pages":"1871-1874"},"PeriodicalIF":3.4,"publicationDate":"2025-08-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145455858","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 : 2025-08-04DOI: 10.1109/LMWT.2025.3591250
Mattia Mengozzi;Wissam Saabe;Alberto M. Angelotti;Wafae El Fennouri;Christophe Mazière;Tony Gasseling;Gian Piero Gibiino
This work validates a behavioral modeling and measurement-based emulation framework for active phased arrays (APAs). Dataset collection time for power amplifier (PA) modeling is minimized using fast active load–pull, while validation employs measurement-based APA emulation to replicate beam steering operating conditions. Simulations closely match the measurement-based emulation of a $2 times 2$ patch-antenna APA for a 64-QAM orthogonal frequency-division multiplexing (OFDM) signal at 27 GHz across a wide range of beam angles, demonstrating the framework’s effectiveness for APA design and analysis.
{"title":"Experimental Validation of a System-Level Model for Active Arrays Under Emulated Beam Steering","authors":"Mattia Mengozzi;Wissam Saabe;Alberto M. Angelotti;Wafae El Fennouri;Christophe Mazière;Tony Gasseling;Gian Piero Gibiino","doi":"10.1109/LMWT.2025.3591250","DOIUrl":"https://doi.org/10.1109/LMWT.2025.3591250","url":null,"abstract":"This work validates a behavioral modeling and measurement-based emulation framework for active phased arrays (APAs). Dataset collection time for power amplifier (PA) modeling is minimized using fast active load–pull, while validation employs measurement-based APA emulation to replicate beam steering operating conditions. Simulations closely match the measurement-based emulation of a <inline-formula> <tex-math>$2 times 2$ </tex-math></inline-formula> patch-antenna APA for a 64-QAM orthogonal frequency-division multiplexing (OFDM) signal at 27 GHz across a wide range of beam angles, demonstrating the framework’s effectiveness for APA design and analysis.","PeriodicalId":73297,"journal":{"name":"IEEE microwave and wireless technology letters","volume":"35 11","pages":"1863-1866"},"PeriodicalIF":3.4,"publicationDate":"2025-08-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145455872","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 : 2025-08-01DOI: 10.1109/LMWT.2025.3592473
Bangji Wang;Xin Li;Song Qiu;Yuping Shang
Traditional chokes in high-power microwaves (HPMs) often suffer from electromagnetic resonances and strict shape dependence. A conformal and miniaturized choke incorporating special slot structures is proposed in this letter. The narrow Slot 1 loaded perpendicular to the noncontact gap forms a surface with resonance suppression capabilities. In addition, the introduction of Slot 2 establishes an electromagnetic bandgap (EBG) with high-power handling capabilities, effectively preventing leakage. More importantly, the conformal and miniaturized design schemes of the proposed choke were analyzed and developed. A practical implementation case was evaluated through simulations and experiments, confirming its significant performance. Compared to conventional designs, this choke exhibits significant advantages in adapting complex geometrical configurations of HPM.
{"title":"A Conformal and Miniaturized Choke for Resonance Suppression and Leakage Prevention in High-Power Microwaves","authors":"Bangji Wang;Xin Li;Song Qiu;Yuping Shang","doi":"10.1109/LMWT.2025.3592473","DOIUrl":"https://doi.org/10.1109/LMWT.2025.3592473","url":null,"abstract":"Traditional chokes in high-power microwaves (HPMs) often suffer from electromagnetic resonances and strict shape dependence. A conformal and miniaturized choke incorporating special slot structures is proposed in this letter. The narrow Slot 1 loaded perpendicular to the noncontact gap forms a surface with resonance suppression capabilities. In addition, the introduction of Slot 2 establishes an electromagnetic bandgap (EBG) with high-power handling capabilities, effectively preventing leakage. More importantly, the conformal and miniaturized design schemes of the proposed choke were analyzed and developed. A practical implementation case was evaluated through simulations and experiments, confirming its significant performance. Compared to conventional designs, this choke exhibits significant advantages in adapting complex geometrical configurations of HPM.","PeriodicalId":73297,"journal":{"name":"IEEE microwave and wireless technology letters","volume":"35 9","pages":"1332-1335"},"PeriodicalIF":3.4,"publicationDate":"2025-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145078627","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 : 2025-07-30DOI: 10.1109/LMWT.2025.3592189
Jingzhan Shi;Zeyu Wang;Dan Zhu;Qiang Liu;Dongdong Lin;Na Zhang;Bindong Gao;Yiping Cui;Yiping Wang
Microwave photonic frequency-to-phase-slope mapping (FTPSM) is susceptible to frequency measurement errors, primarily induced by delay-rate uncertainty and fluctuations. To address this limitation, we propose a novel frequency-to-phase-slope-ratio mapping (FTPSRM) method that incorporates a reference signal sharing the same time-varying delay path as the signal under test (SUT). By leveraging the phase-slope ratio, this approach eliminates the need for delay-rate calibration while mitigating the impact of delay-rate fluctuations on measurement accuracy. The FTPSRM is implemented in a microwave photonic system utilizing polarization-division multiplexing of time-varying delay. The experimental results demonstrate that the FTPSRM reduces the maximum frequency error from 602 to 234 MHz and the standard deviation from 743 to 301 MHz across the 1–10-GHz range, significantly improving both accuracy and stability under delay fluctuations.
{"title":"Microwave Frequency-to-Phase-Slope-Ratio Mapping via Photonic Polarization-Division Multiplexing of Time-Varying Delay","authors":"Jingzhan Shi;Zeyu Wang;Dan Zhu;Qiang Liu;Dongdong Lin;Na Zhang;Bindong Gao;Yiping Cui;Yiping Wang","doi":"10.1109/LMWT.2025.3592189","DOIUrl":"https://doi.org/10.1109/LMWT.2025.3592189","url":null,"abstract":"Microwave photonic frequency-to-phase-slope mapping (FTPSM) is susceptible to frequency measurement errors, primarily induced by delay-rate uncertainty and fluctuations. To address this limitation, we propose a novel frequency-to-phase-slope-ratio mapping (FTPSRM) method that incorporates a reference signal sharing the same time-varying delay path as the signal under test (SUT). By leveraging the phase-slope ratio, this approach eliminates the need for delay-rate calibration while mitigating the impact of delay-rate fluctuations on measurement accuracy. The FTPSRM is implemented in a microwave photonic system utilizing polarization-division multiplexing of time-varying delay. The experimental results demonstrate that the FTPSRM reduces the maximum frequency error from 602 to 234 MHz and the standard deviation from 743 to 301 MHz across the 1–10-GHz range, significantly improving both accuracy and stability under delay fluctuations.","PeriodicalId":73297,"journal":{"name":"IEEE microwave and wireless technology letters","volume":"35 11","pages":"1867-1870"},"PeriodicalIF":3.4,"publicationDate":"2025-07-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145455870","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 : 2025-07-29DOI: 10.1109/LMWT.2025.3591525
Pujan K. C. Mishu;Ebrahim M. Al Seragi;Waleed Ahmad;Alireza Kiyaei;Saeed Zeinolabedinzadeh
This letter presents a SiGe heterojunction bipolar transistor (SiGe HBT)-based N-path receiver with a simple noise-reduction feedback path to improve the overall noise of the receiver. Noise from local oscillator (LO) switches constitutes a significant portion of the total noise in N-path architecture at millimeter-wave (mmW) frequencies. The switch noise increases when sinusoidal LO signals are used, particularly in the absence of a perfect nonoverlapping LO signal at mmW frequencies. To reduce the switch noise, we implemented a negative feedback path, which helps reduce the noise from the switch and LO buffers. In this work, two SiGe HBT-based N-path receivers with and without feedback networks were fabricated in 130-nm SiGe BiCMOS technology, where the receiver with feedback network shows 8-dB lower noise figure (NF) compared to the architecture without feedback system at 28 GHz. The fabricated chip shows a conversion gain of −5.9 dB and P1dB of −16.42 dBm at 30 GHz.
{"title":"SiGe HBT-Based N-Path Receiver With Improved Noise Figure","authors":"Pujan K. C. Mishu;Ebrahim M. Al Seragi;Waleed Ahmad;Alireza Kiyaei;Saeed Zeinolabedinzadeh","doi":"10.1109/LMWT.2025.3591525","DOIUrl":"https://doi.org/10.1109/LMWT.2025.3591525","url":null,"abstract":"This letter presents a SiGe heterojunction bipolar transistor (SiGe HBT)-based <italic>N</i>-path receiver with a simple noise-reduction feedback path to improve the overall noise of the receiver. Noise from local oscillator (LO) switches constitutes a significant portion of the total noise in <italic>N</i>-path architecture at millimeter-wave (mmW) frequencies. The switch noise increases when sinusoidal LO signals are used, particularly in the absence of a perfect nonoverlapping LO signal at mmW frequencies. To reduce the switch noise, we implemented a negative feedback path, which helps reduce the noise from the switch and LO buffers. In this work, two SiGe HBT-based <italic>N</i>-path receivers with and without feedback networks were fabricated in 130-nm SiGe BiCMOS technology, where the receiver with feedback network shows 8-dB lower noise figure (NF) compared to the architecture without feedback system at 28 GHz. The fabricated chip shows a conversion gain of −5.9 dB and P1dB of −16.42 dBm at 30 GHz.","PeriodicalId":73297,"journal":{"name":"IEEE microwave and wireless technology letters","volume":"35 11","pages":"1851-1854"},"PeriodicalIF":3.4,"publicationDate":"2025-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145455871","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 : 2025-07-29DOI: 10.1109/LMWT.2025.3590791
Shuoguo Huang;Ximing Lv;Yongwen Yin;Tianyang Zhong;Junfu Guo;Cheng Zhong;Chuan Li;Songbai He
In this letter, an inline mismatch measurement and correction system is proposed to address production inconsistencies in compact RF links. The system aims to restore the performance of RF link affected by manufacturing errors and assembly inconsistencies. Based on a neural network (NN)-enhanced calculation algorithm that accounts for nonidealities, the mismatch of PA is accurately measured and then corrected using a laser-etching tunable matching network (LE-TMN) with low insertion loss. Experimental results demonstrate that the proposed system achieves a high-accuracy mismatch measurement, with absolute errors in reflection coefficient magnitude below 1.11 dB and absolute phase errors within 5° across the 1.5–2.5 GHz, for reflection coefficient magnitudes ranging from −5 to −35 dB. Furthermore, a prototype is set up, and its effectiveness in restoring link performance is validated through continuous wave (CW) and modulated signal tests, demonstrating notable improvements in output power, efficiency, and linearity.
{"title":"Inline Impedance Mismatch Measurement and Correction System With Enhanced Accuracy and Low Insertion Loss for Mass Production of Compact RF Links","authors":"Shuoguo Huang;Ximing Lv;Yongwen Yin;Tianyang Zhong;Junfu Guo;Cheng Zhong;Chuan Li;Songbai He","doi":"10.1109/LMWT.2025.3590791","DOIUrl":"https://doi.org/10.1109/LMWT.2025.3590791","url":null,"abstract":"In this letter, an inline mismatch measurement and correction system is proposed to address production inconsistencies in compact RF links. The system aims to restore the performance of RF link affected by manufacturing errors and assembly inconsistencies. Based on a neural network (NN)-enhanced calculation algorithm that accounts for nonidealities, the mismatch of PA is accurately measured and then corrected using a laser-etching tunable matching network (LE-TMN) with low insertion loss. Experimental results demonstrate that the proposed system achieves a high-accuracy mismatch measurement, with absolute errors in reflection coefficient magnitude below 1.11 dB and absolute phase errors within 5° across the 1.5–2.5 GHz, for reflection coefficient magnitudes ranging from −5 to −35 dB. Furthermore, a prototype is set up, and its effectiveness in restoring link performance is validated through continuous wave (CW) and modulated signal tests, demonstrating notable improvements in output power, efficiency, and linearity.","PeriodicalId":73297,"journal":{"name":"IEEE microwave and wireless technology letters","volume":"35 11","pages":"1859-1862"},"PeriodicalIF":3.4,"publicationDate":"2025-07-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145455935","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}
This letter presents a novel online power measurement method for high-power millimeter-wave (MMW) systems. By investigating a model of electromagnetic wave incidence on the multilayer dielectric media, an analytical relationship between the power loss in the dielectric and the incident power was theoretically derived. Combined with temperature-dependent measurements of key parameters, this method enables the power measurement of millisecond level, 100-kW single-pulse high-power MMWs. This approach is expected to complement existing measurement methods, providing a versatile tool for power measurement across different time scales.
{"title":"A Novel Online Power Testing Method for High-Power Millimeter-Wave Systems","authors":"Qili Huang;Linlin Hu;Yi Jiang;Peng Hu;Luqi Zhang;Lijun Yi;Shenggang Gong;Dimin Sun;Guowu Ma;Xiao Jin;Hao Xu","doi":"10.1109/LMWT.2025.3591022","DOIUrl":"https://doi.org/10.1109/LMWT.2025.3591022","url":null,"abstract":"This letter presents a novel online power measurement method for high-power millimeter-wave (MMW) systems. By investigating a model of electromagnetic wave incidence on the multilayer dielectric media, an analytical relationship between the power loss in the dielectric and the incident power was theoretically derived. Combined with temperature-dependent measurements of key parameters, this method enables the power measurement of millisecond level, 100-kW single-pulse high-power MMWs. This approach is expected to complement existing measurement methods, providing a versatile tool for power measurement across different time scales.","PeriodicalId":73297,"journal":{"name":"IEEE microwave and wireless technology letters","volume":"35 11","pages":"1855-1858"},"PeriodicalIF":3.4,"publicationDate":"2025-07-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145455823","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 : 2025-07-18DOI: 10.1109/LMWT.2025.3588842
Wei Xiao;Xinyue Gao;Yawen Wang
This letter introduces an effective method to enhance microwave heating uniformity by equipping an active frequency selective surface (AFSS) working at 2.45 GHz within microwave cavities. By changing the on/off states of p-i-n diodes embedded at different locations on the AFSS, the proposed method achieves the redistribution of the electric field in the microwave cavity. Simulations demonstrate an increase of over 36% in heating uniformity across different heated samples through diode state control. To validate this method, a microwave heating system is customized to conduct temperature measurements. Good agreement is achieved between simulations and experiments, verifying the validity of this method.
{"title":"Loading an Active Frequency Selective Surface in Microwave Cavities to Enhance Heating Uniformity","authors":"Wei Xiao;Xinyue Gao;Yawen Wang","doi":"10.1109/LMWT.2025.3588842","DOIUrl":"https://doi.org/10.1109/LMWT.2025.3588842","url":null,"abstract":"This letter introduces an effective method to enhance microwave heating uniformity by equipping an active frequency selective surface (AFSS) working at 2.45 GHz within microwave cavities. By changing the <sc>on</small>/<sc>off</small> states of p-i-n diodes embedded at different locations on the AFSS, the proposed method achieves the redistribution of the electric field in the microwave cavity. Simulations demonstrate an increase of over 36% in heating uniformity across different heated samples through diode state control. To validate this method, a microwave heating system is customized to conduct temperature measurements. Good agreement is achieved between simulations and experiments, verifying the validity of this method.","PeriodicalId":73297,"journal":{"name":"IEEE microwave and wireless technology letters","volume":"35 10","pages":"1642-1645"},"PeriodicalIF":3.4,"publicationDate":"2025-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145242606","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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