Pub Date : 2025-09-17DOI: 10.1109/TMTT.2025.3596357
Natalia K. Nikolova;Peter H. Aaen
{"title":"NEMO 2024 Special Issue Guest Editorial","authors":"Natalia K. Nikolova;Peter H. Aaen","doi":"10.1109/TMTT.2025.3596357","DOIUrl":"https://doi.org/10.1109/TMTT.2025.3596357","url":null,"abstract":"","PeriodicalId":13272,"journal":{"name":"IEEE Transactions on Microwave Theory and Techniques","volume":"73 9","pages":"6049-6050"},"PeriodicalIF":4.5,"publicationDate":"2025-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11169304","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145073249","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 : 2025-09-17DOI: 10.1109/TMTT.2025.3559914
Jiachen Guo;Yuchen Cao;Kenle Chen
The authors appreciate the comments and corrections made by Wei et al. [1] that point out errors in [2]. Based on the feedback and a thorough rederivation, we have identified and corrected inaccuracies in the theoretical derivation to ensure consistency in the theoretical framework. While the main conclusions of [2] remain valid, we regret any inconvenience caused by these errors.
作者感谢Wei et al.[1]所做的评论和更正，指出[2]中的错误。根据反馈和彻底的重新推导，我们已经确定并纠正了理论推导中的不准确之处，以确保理论框架的一致性。虽然b[2]的主要结论仍然有效，但我们对这些错误造成的任何不便表示歉意。
{"title":"Corrections to “Linear Hybrid Asymmetrical Load-Modulated Balanced Amplifier With Multiband Reconfigurability and Antenna-VSWR Resilience”","authors":"Jiachen Guo;Yuchen Cao;Kenle Chen","doi":"10.1109/TMTT.2025.3559914","DOIUrl":"https://doi.org/10.1109/TMTT.2025.3559914","url":null,"abstract":"The authors appreciate the comments and corrections made by Wei et al. [1] that point out errors in [2]. Based on the feedback and a thorough rederivation, we have identified and corrected inaccuracies in the theoretical derivation to ensure consistency in the theoretical framework. While the main conclusions of [2] remain valid, we regret any inconvenience caused by these errors.","PeriodicalId":13272,"journal":{"name":"IEEE Transactions on Microwave Theory and Techniques","volume":"73 9","pages":"6964-6964"},"PeriodicalIF":4.5,"publicationDate":"2025-09-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11169320","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145073261","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}
Photonics-aided millimeter-wave communication (PMC) offers the advantage of wide bandwidth, enabling the integration of fiber-wireless links for ultralong-distance, high-capacity transmission. However, due to the temperature drift and large linewidth of laser sources, photonics-aided millimeter-wave transmission often requires more complex digital signal processing (DSP) to manage frequency offsets of several hundred megahertz and residual phase offsets of several hundred kilohertz, which significantly increases the resources of the receiver-end DSP. Moreover, in real-time communication scenarios, the sampling frequency offset (SFO) caused by the mismatch between the transmitter and receiver rates affects the symbol synchronization (SS) at the receiver and the performance of the adaptive filter. In this article, we propose an optimized DSP architecture for the photonics-aided millimeter-wave backend, where a novel SS scheme is implemented to address the issue of transceiver-rate mismatch. This scheme leverages the tracking characteristics of a fractional adaptive equalizer. Furthermore, we design a novel frequency offset estimation (FOE) architecture by utilizing phase ambiguity in conventional phase offset estimation algorithm, and we present a variant of this architecture for higher order modulation formats. Both novel SS and FOE method are modulation-format compatible. We have completed the performance evaluation of the new SS and FOE methods in simulations. Finally, we have implemented full-process real-time receiver DSP flow on field-programmable gate array (FPGA), demonstrating real-time equalization and recovery of photonics-aided millimeter-wave signals. This system is experimentally validated and successfully achieved 4.6-km antenna polarization multiplexing photonics-aided millimeter-wave wireless transmission.
{"title":"Photonic MMW Real-Time System: FPGA-Enabled Low-Complexity Frequency Offset Estimation and Symbol Synchronization","authors":"Tianqi Zheng;Kaihui Wang;Sheng Hu;Xiongwei Yang;Mingxu Wang;Chengzhen Bian;Wen Zhou;Jianjun Yu","doi":"10.1109/TMTT.2025.3603455","DOIUrl":"https://doi.org/10.1109/TMTT.2025.3603455","url":null,"abstract":"Photonics-aided millimeter-wave communication (PMC) offers the advantage of wide bandwidth, enabling the integration of fiber-wireless links for ultralong-distance, high-capacity transmission. However, due to the temperature drift and large linewidth of laser sources, photonics-aided millimeter-wave transmission often requires more complex digital signal processing (DSP) to manage frequency offsets of several hundred megahertz and residual phase offsets of several hundred kilohertz, which significantly increases the resources of the receiver-end DSP. Moreover, in real-time communication scenarios, the sampling frequency offset (SFO) caused by the mismatch between the transmitter and receiver rates affects the symbol synchronization (SS) at the receiver and the performance of the adaptive filter. In this article, we propose an optimized DSP architecture for the photonics-aided millimeter-wave backend, where a novel SS scheme is implemented to address the issue of transceiver-rate mismatch. This scheme leverages the tracking characteristics of a fractional adaptive equalizer. Furthermore, we design a novel frequency offset estimation (FOE) architecture by utilizing phase ambiguity in conventional phase offset estimation algorithm, and we present a variant of this architecture for higher order modulation formats. Both novel SS and FOE method are modulation-format compatible. We have completed the performance evaluation of the new SS and FOE methods in simulations. Finally, we have implemented full-process real-time receiver DSP flow on field-programmable gate array (FPGA), demonstrating real-time equalization and recovery of photonics-aided millimeter-wave signals. This system is experimentally validated and successfully achieved 4.6-km antenna polarization multiplexing photonics-aided millimeter-wave wireless transmission.","PeriodicalId":13272,"journal":{"name":"IEEE Transactions on Microwave Theory and Techniques","volume":"73 11","pages":"9605-9615"},"PeriodicalIF":4.5,"publicationDate":"2025-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145595130","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 : 2025-09-16DOI: 10.1109/TMTT.2025.3606886
Chi Jiang;Taixia Shi;Dingding Liang;Lei Gao;Chulun Lin;Yang Chen
In response to the urgent demand for the development of future radar application platforms from single radar functionality toward integrated multifunctional systems, we show an advanced microwave photonic waveform editing method that enables the editing of arbitrary radar waveforms, equipping them with the capability to perform spectrum sensing. This, in turn, expands single-function radar systems into joint radar and spectrum-sensing systems. We theoretically define and calculate the accumulation function of an arbitrary waveform after passing through a specific dispersive medium and utilize this accumulation function to further design a corresponding binary sequence for editing the waveform. After editing, the accumulation function of the edited waveform approximates that of a linearly frequency-modulated (LFM) signal matching the specific dispersive medium. Thus, the edited waveform can be compressed into a narrow pulse after passing through the dispersive medium, realizing the frequency-to-time mapping (FTTM) for achieving frequency measurement or time–frequency analysis. The concept is verified through both simulation and experiment. Using a dispersion-compensating fiber (DCF) with a total dispersion of −6817 ps/nm, arbitrary waveforms, including a 7-bit Barker phase-coded waveform, an LFM waveform, a nonlinearly frequency-modulated (NLFM) waveform, and a waveform with an “E” time–frequency diagram, are edited and further used for microwave frequency measurement and time–frequency analysis in an ultra-wide bandwidth of 36.8 GHz. The temporal resolution and frequency resolution are 2 ns and 0.86 GHz, respectively.
{"title":"Advanced Microwave Photonic Waveform Editing: Enabling the Evolution of Radar Systems Into Joint Radar and Spectrum-Sensing Systems","authors":"Chi Jiang;Taixia Shi;Dingding Liang;Lei Gao;Chulun Lin;Yang Chen","doi":"10.1109/TMTT.2025.3606886","DOIUrl":"https://doi.org/10.1109/TMTT.2025.3606886","url":null,"abstract":"In response to the urgent demand for the development of future radar application platforms from single radar functionality toward integrated multifunctional systems, we show an advanced microwave photonic waveform editing method that enables the editing of arbitrary radar waveforms, equipping them with the capability to perform spectrum sensing. This, in turn, expands single-function radar systems into joint radar and spectrum-sensing systems. We theoretically define and calculate the accumulation function of an arbitrary waveform after passing through a specific dispersive medium and utilize this accumulation function to further design a corresponding binary sequence for editing the waveform. After editing, the accumulation function of the edited waveform approximates that of a linearly frequency-modulated (LFM) signal matching the specific dispersive medium. Thus, the edited waveform can be compressed into a narrow pulse after passing through the dispersive medium, realizing the frequency-to-time mapping (FTTM) for achieving frequency measurement or time–frequency analysis. The concept is verified through both simulation and experiment. Using a dispersion-compensating fiber (DCF) with a total dispersion of −6817 ps/nm, arbitrary waveforms, including a 7-bit Barker phase-coded waveform, an LFM waveform, a nonlinearly frequency-modulated (NLFM) waveform, and a waveform with an “E” time–frequency diagram, are edited and further used for microwave frequency measurement and time–frequency analysis in an ultra-wide bandwidth of 36.8 GHz. The temporal resolution and frequency resolution are 2 ns and 0.86 GHz, respectively.","PeriodicalId":13272,"journal":{"name":"IEEE Transactions on Microwave Theory and Techniques","volume":"73 12","pages":"10711-10723"},"PeriodicalIF":4.5,"publicationDate":"2025-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145778239","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 : 2025-09-16DOI: 10.1109/TMTT.2025.3605931
Yuanzhe Li;Weidong Hu;Hongqi Fan;Xiaoyong Du;Dawei Lu;Peiguo Liu
Nonlinear radar has garnered significant attention in recent years due to its unique advantage in detecting man-made electronics under strong clutter conditions. Currently, nonlinear radars primarily rely on harmonic and intermodulation (IM) signatures, where the generation of new frequency components is the defining feature of nonlinear scattering. However, this work breaks ground by exploiting the discrepancies of power-dependent response as an alternative nonlinear characterization and detection paradigm. We propose simultaneous multipower-scale excitation (SMPSE), which integrates large and small signals to concurrently capture scattering characteristics across different power levels. The intrinsic constraint relationships (ICRs) between the power-dependent scattering parameters and IM efficiency are further revealed, which is validated by the measured data of typical RF front-end targets. Furthermore, a stepped-SMPSE methodology for nonlinear detection is proposed based on ICRs, which successfully achieves simultaneous linear and nonlinear range profile estimation with 4-GHz bandwidth in over-the-air (OTA) experiments. The proposed method holds great potential for precise diagnostic localization of nonlinear nodes and novel radar systems simultaneously integrating linear and nonlinear signatures.
{"title":"Nonlinear Characterization and Detection Using Simultaneous Multipower-Scale Excitation","authors":"Yuanzhe Li;Weidong Hu;Hongqi Fan;Xiaoyong Du;Dawei Lu;Peiguo Liu","doi":"10.1109/TMTT.2025.3605931","DOIUrl":"https://doi.org/10.1109/TMTT.2025.3605931","url":null,"abstract":"Nonlinear radar has garnered significant attention in recent years due to its unique advantage in detecting man-made electronics under strong clutter conditions. Currently, nonlinear radars primarily rely on harmonic and intermodulation (IM) signatures, where the generation of new frequency components is the defining feature of nonlinear scattering. However, this work breaks ground by exploiting the discrepancies of power-dependent response as an alternative nonlinear characterization and detection paradigm. We propose simultaneous multipower-scale excitation (SMPSE), which integrates large and small signals to concurrently capture scattering characteristics across different power levels. The intrinsic constraint relationships (ICRs) between the power-dependent scattering parameters and IM efficiency are further revealed, which is validated by the measured data of typical RF front-end targets. Furthermore, a stepped-SMPSE methodology for nonlinear detection is proposed based on ICRs, which successfully achieves simultaneous linear and nonlinear range profile estimation with 4-GHz bandwidth in over-the-air (OTA) experiments. The proposed method holds great potential for precise diagnostic localization of nonlinear nodes and novel radar systems simultaneously integrating linear and nonlinear signatures.","PeriodicalId":13272,"journal":{"name":"IEEE Transactions on Microwave Theory and Techniques","volume":"73 12","pages":"10758-10770"},"PeriodicalIF":4.5,"publicationDate":"2025-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145778188","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 : 2025-09-16DOI: 10.1109/TMTT.2025.3608854
Ke Huang;Xiaoli Zhi;Yue Yu;Tianhao Lu;Bin Zhang;Qiangli Xi;Zhongbo Zhu;Shixiong Liang;Lixin Ran
Terahertz (THz) large-scale phased arrays for sixth-generation (6G) communication face integration challenges with T/R modules due to their millimeter-scale dimensions. While reconfigurable transmitarrays (RTAs) enable scalable implementations without bulky feed networks, most reported designs are limited to 1-D steering or rely on complex structures that pose challenges for monolithic fabrication. As a solution, we propose and implement a 210–220-GHz amplitude-RTA (ARTA) system. The ARTA features a single-layer, via-free chip design, with a Schottky barrier diode (SBD) monolithically integrated on each element, enabling element-wise reconfigurability of transmittance to incident waves while reducing fabrication cost and complexity. Meanwhile, an optimal 1-bit amplitude modulation strategy for ARTA beam steering is developed with maximized modulation efficiency. A $5.7times 5.7$ -$lambda $ ARTA chip, consisting of $20times 20$ elements, was fabricated on a gallium arsenide (GaAs) wafer. Based on this chip, a compact, portable $20times 20$ ARTA system was implemented by integrating dedicated beam-control circuits and a THz RF chain, enabling high-speed THz communication with real-time 2-D beam steering. Numerical and experimental results validate that, with the proposed modulation strategy, the ARTA system can steer beams over ±30° in the H-plane and from −30° to 20° in the E-plane, demonstrating potential for high-speed beam steering, such as multinode communication in satellite networks.
{"title":"Monolithic GaAs Transmitarray With Amplitude Reconfigurability for 2-D Terahertz Beam Steering","authors":"Ke Huang;Xiaoli Zhi;Yue Yu;Tianhao Lu;Bin Zhang;Qiangli Xi;Zhongbo Zhu;Shixiong Liang;Lixin Ran","doi":"10.1109/TMTT.2025.3608854","DOIUrl":"https://doi.org/10.1109/TMTT.2025.3608854","url":null,"abstract":"Terahertz (THz) large-scale phased arrays for sixth-generation (6G) communication face integration challenges with T/R modules due to their millimeter-scale dimensions. While reconfigurable transmitarrays (RTAs) enable scalable implementations without bulky feed networks, most reported designs are limited to 1-D steering or rely on complex structures that pose challenges for monolithic fabrication. As a solution, we propose and implement a 210–220-GHz amplitude-RTA (ARTA) system. The ARTA features a single-layer, via-free chip design, with a Schottky barrier diode (SBD) monolithically integrated on each element, enabling element-wise reconfigurability of transmittance to incident waves while reducing fabrication cost and complexity. Meanwhile, an optimal 1-bit amplitude modulation strategy for ARTA beam steering is developed with maximized modulation efficiency. A <inline-formula> <tex-math>$5.7times 5.7$ </tex-math></inline-formula>-<inline-formula> <tex-math>$lambda $ </tex-math></inline-formula> ARTA chip, consisting of <inline-formula> <tex-math>$20times 20$ </tex-math></inline-formula> elements, was fabricated on a gallium arsenide (GaAs) wafer. Based on this chip, a compact, portable <inline-formula> <tex-math>$20times 20$ </tex-math></inline-formula> ARTA system was implemented by integrating dedicated beam-control circuits and a THz RF chain, enabling high-speed THz communication with real-time 2-D beam steering. Numerical and experimental results validate that, with the proposed modulation strategy, the ARTA system can steer beams over ±30° in the <italic>H</i>-plane and from −30° to 20° in the <italic>E</i>-plane, demonstrating potential for high-speed beam steering, such as multinode communication in satellite networks.","PeriodicalId":13272,"journal":{"name":"IEEE Transactions on Microwave Theory and Techniques","volume":"73 12","pages":"10799-10813"},"PeriodicalIF":4.5,"publicationDate":"2025-09-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145778232","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}
In this experiment, we demonstrated a photon-assisted terahertz (THz) wireless transmission system based on a field-programmable gate array (FPGA). By utilizing envelope detection and antenna polarization multiplexing, the system successfully achieves 105-Gb/s data transmission over a wireless distance of 3 m. To support this, low-complexity resampling and equalization modules were implemented on the FPGA. For resampling, a nonrecursive cascaded integrator-comb (NR-CIC) filter was used to achieve an upsampling factor of 1.75. For equalization, we innovatively introduced the decision-quantized equalization (DQ-Eq) algorithm. Experimental results indicate that the optimized NR-CIC filter attains antialiasing performance equivalent to a conventional 41-tap time-domain (TD) filter. Moreover, compared to the signsign equalization, DQ-Eq exhibits faster convergence speed and a lower bit error rate (BER). Compared with traditional equalization, DQ-Eq reduces computational complexity by 13.8%, thereby significantly improving the efficiency of hardware implementation. These experimental results fully validate the advantage of the proposed scheme in reducing computational complexity, providing an effective and practical solution for real-time THz wireless communication in future 6G networks.
{"title":"105-Gb/s Photonics-Aided THz Communication With FPGA-Based Low-Complexity Resampling and Equalization","authors":"Yikai Wang;Junjie Ding;Min Zhu;Long Zhang;Jia Meng;Weidong Tong;Zhigang Xin;Yuancheng Cai;Jiao Zhang;Bingchang Hua;Mingzheng Lei;Kaihui Wang;Jianjun Yu","doi":"10.1109/TMTT.2025.3605607","DOIUrl":"https://doi.org/10.1109/TMTT.2025.3605607","url":null,"abstract":"In this experiment, we demonstrated a photon-assisted terahertz (THz) wireless transmission system based on a field-programmable gate array (FPGA). By utilizing envelope detection and antenna polarization multiplexing, the system successfully achieves 105-Gb/s data transmission over a wireless distance of 3 m. To support this, low-complexity resampling and equalization modules were implemented on the FPGA. For resampling, a nonrecursive cascaded integrator-comb (NR-CIC) filter was used to achieve an upsampling factor of 1.75. For equalization, we innovatively introduced the decision-quantized equalization (DQ-Eq) algorithm. Experimental results indicate that the optimized NR-CIC filter attains antialiasing performance equivalent to a conventional 41-tap time-domain (TD) filter. Moreover, compared to the signsign equalization, DQ-Eq exhibits faster convergence speed and a lower bit error rate (BER). Compared with traditional equalization, DQ-Eq reduces computational complexity by 13.8%, thereby significantly improving the efficiency of hardware implementation. These experimental results fully validate the advantage of the proposed scheme in reducing computational complexity, providing an effective and practical solution for real-time THz wireless communication in future 6G networks.","PeriodicalId":13272,"journal":{"name":"IEEE Transactions on Microwave Theory and Techniques","volume":"73 12","pages":"10700-10710"},"PeriodicalIF":4.5,"publicationDate":"2025-09-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145778153","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}
In this work, a design scheme for a tunable waveguide phase shifter is proposed, which utilizes anisotropic artificial electromagnetic materials (AEMs). The configuration scheme consists of a rectangular waveguide integrated with a split-ring resonator (SRR) dielectric substrate. The design scheme treats the SRR on the dielectric substrate as a unit cell of anisotropic AEMs. By optimizing their structural parameters, the material properties (permittivity and permeability) can be systematically engineered, where each parameter set corresponds to a distinct phase-shifting state. This approach theoretically enables high-precision phase-shifter performance. Through theoretical analysis, the impact of material property variations on the phase shifter’s insertion loss and phase shifting is quantitatively analyzed. Ultimately, a 360° tunable waveguide phase shifter is successfully designed based on the proposed AEM unit. The design is further optimized for compactness, realizing 360° continuous phase-tuning capability concurrently with a significant volume reduction of the phase-shifting structure by 50%. The proposed phase shifter demonstrates not only high-precision performance but also cost-effective fabrication advantages. To validate the design effectiveness, prototype testing is conducted, showing excellent agreement between measured results and simulation results.
{"title":"360° Tunable Waveguide Phase Shifter Based on Anisotropic Artificial Electromagnetic Materials","authors":"Shu-Qing Zhang;Sai-Wai Wong;Zhonghe Zhang;Muhammad Uzair","doi":"10.1109/TMTT.2025.3603894","DOIUrl":"https://doi.org/10.1109/TMTT.2025.3603894","url":null,"abstract":"In this work, a design scheme for a tunable waveguide phase shifter is proposed, which utilizes anisotropic artificial electromagnetic materials (AEMs). The configuration scheme consists of a rectangular waveguide integrated with a split-ring resonator (SRR) dielectric substrate. The design scheme treats the SRR on the dielectric substrate as a unit cell of anisotropic AEMs. By optimizing their structural parameters, the material properties (permittivity and permeability) can be systematically engineered, where each parameter set corresponds to a distinct phase-shifting state. This approach theoretically enables high-precision phase-shifter performance. Through theoretical analysis, the impact of material property variations on the phase shifter’s insertion loss and phase shifting is quantitatively analyzed. Ultimately, a 360° tunable waveguide phase shifter is successfully designed based on the proposed AEM unit. The design is further optimized for compactness, realizing 360° continuous phase-tuning capability concurrently with a significant volume reduction of the phase-shifting structure by 50%. The proposed phase shifter demonstrates not only high-precision performance but also cost-effective fabrication advantages. To validate the design effectiveness, prototype testing is conducted, showing excellent agreement between measured results and simulation results.","PeriodicalId":13272,"journal":{"name":"IEEE Transactions on Microwave Theory and Techniques","volume":"73 12","pages":"10590-10605"},"PeriodicalIF":4.5,"publicationDate":"2025-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145830878","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 : 2025-09-05DOI: 10.1109/TMTT.2025.3602740
Samuel Weller;Shyqyri Haxha;Jaione Galdeano;Iain McKenzie
In this article, we explore the use of gradient-based optimization algorithms for automated bias control in Mach–Zehnder modulators (MZMs). We present and demonstrate, experimentally, five gradient descent (GD) algorithms—stochastic GD (SGD), SGD with momentum (SGD+M), Adagrad, RMSProp, and Adam—applied to the bias control problem in MZMs. We present a method of creating an error signal from the measured output of an MZM with a low-frequency pilot tone and provide a detailed explanation of how each algorithm is used to both identify the set bias condition and track the bias condition in the presence of disturbances. Our implementation is capable of identifying and holding the null condition and the quadrature condition. We evaluate the bias point identification for each algorithm by measuring and analyzing the step response for each method. We test the bias tracking of each algorithm using three forms of disturbance—radio frequency (RF) power disturbances, temperature disturbance, and long-term bias drift. All tests were conducted at 20 GHz. To the best of our knowledge, this is the first investigation into the application on gradient-based learning approaches for MZM bias control. This work has great importance on future bias control design and implementations for telecommunications, the space sector, microwave photonics (MWPs), and defense.
在本文中，我们探讨了在马赫-曾德调制器（MZMs）中使用基于梯度的优化算法进行自动偏置控制。我们提出并实验证明了五种梯度下降（GD）算法-随机GD (SGD), SGD with momentum (SGD+M), Adagrad， RMSProp和adam -应用于MZMs中的偏差控制问题。我们提出了一种从具有低频导频音的MZM的测量输出中产生误差信号的方法，并详细解释了如何使用每种算法来识别设置的偏置条件并在存在干扰的情况下跟踪偏置条件。我们的实现能够识别和保持零条件和正交条件。我们通过测量和分析每种方法的阶跃响应来评估每种算法的偏置点识别。我们使用三种形式的干扰——射频（RF）功率干扰、温度干扰和长期偏置漂移——来测试每种算法的偏置跟踪。所有测试均在20 GHz频段进行。据我们所知，这是第一次研究基于梯度的学习方法在MZM偏差控制中的应用。这项工作对未来电信、空间部门、微波光子学（MWPs）和国防的偏置控制设计和实现具有重要意义。
{"title":"Bias Control for Mach–Zehnder Modulators: A Gradient-Based Optimization Approach","authors":"Samuel Weller;Shyqyri Haxha;Jaione Galdeano;Iain McKenzie","doi":"10.1109/TMTT.2025.3602740","DOIUrl":"https://doi.org/10.1109/TMTT.2025.3602740","url":null,"abstract":"In this article, we explore the use of gradient-based optimization algorithms for automated bias control in Mach–Zehnder modulators (MZMs). We present and demonstrate, experimentally, five gradient descent (GD) algorithms—stochastic GD (SGD), SGD with momentum (SGD+M), Adagrad, RMSProp, and Adam—applied to the bias control problem in MZMs. We present a method of creating an error signal from the measured output of an MZM with a low-frequency pilot tone and provide a detailed explanation of how each algorithm is used to both identify the set bias condition and track the bias condition in the presence of disturbances. Our implementation is capable of identifying and holding the null condition and the quadrature condition. We evaluate the bias point identification for each algorithm by measuring and analyzing the step response for each method. We test the bias tracking of each algorithm using three forms of disturbance—radio frequency (RF) power disturbances, temperature disturbance, and long-term bias drift. All tests were conducted at 20 GHz. To the best of our knowledge, this is the first investigation into the application on gradient-based learning approaches for MZM bias control. This work has great importance on future bias control design and implementations for telecommunications, the space sector, microwave photonics (MWPs), and defense.","PeriodicalId":13272,"journal":{"name":"IEEE Transactions on Microwave Theory and Techniques","volume":"73 12","pages":"10678-10690"},"PeriodicalIF":4.5,"publicationDate":"2025-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145778146","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This article presents a 23–30-GHz front end for full-duplex (FD) communication. The front end achieves transmit–receive isolation using an electrical balance duplexer (EBD) that is integrated with a low noise amplifier (LNA) and a power amplifier (PA). The major contributions of this work include presenting a design-oriented approach to analyze EBD–PA cointegration, wherein the EBD is leveraged as part of the PA’s matching network. In addition, this work explores the challenges of achieving simultaneous EBD–PA matching, to maximize power delivery to the antenna, and EBD–antenna matching, to ensure a return loss (RL) greater than 10 dB at the antenna port. As will be demonstrated, reciprocal network constraints for PA matching network, depending on the PA’s output impedance and optimal load, may lead to a suboptimal PA operation to meet these simultaneous matching requirements. The presented EBD is tuned using a programmable balancing network that achieves over 40-dB TX–RX isolation across more than 300-MHz bandwidth, with a simulated IIP3 of +56 dBm while accommodating antenna impedance variations within a 1.22:1 VSWR across the 23–30-GHz band. In addition, a measured isolation exceeding 30 dB over the bandwidth of operation is achieved using a real antenna with a VSWR of up to 1.5:1. The designed PA delivers a simulated output power of +16.5 dBm when loaded by ${Z}_{Ltext {-Opt}}$ at 26 GHz in standalone operation. When integrated with the EBD using the proposed coil design methodology, the delivered power to the EBD’s TX port decreases by 1.3 dB to +15.2 dBm, reflecting the tradeoff associated with simultaneous EBD–PA and EBD–antenna matching. The simulated TX insertion loss (TXIL) of the EBD is 2.3–2.4 dB, and the measured power delivered to the antenna ranges from 11 to 12.9 dBm across the 23–30-GHz band. In the RX path comprising the EBD and LNA, a measured noise figure (NF) of <8.5>2 ($1.98times 1.19$ mm), inclusive of all pads.
{"title":"An mm-Wave Full-Duplex Front End With Integrated LNA, PA, and Electrical Balance Duplexer","authors":"Mohamad Mahdi Rajaei Rizi;Jierui Fu;Mohammad Ghaedi Bardeh;Navid Naseh;Jeyanandh Paramesh;Kamran Entesari","doi":"10.1109/TMTT.2025.3604338","DOIUrl":"https://doi.org/10.1109/TMTT.2025.3604338","url":null,"abstract":"This article presents a 23–30-GHz front end for full-duplex (FD) communication. The front end achieves transmit–receive isolation using an electrical balance duplexer (EBD) that is integrated with a low noise amplifier (LNA) and a power amplifier (PA). The major contributions of this work include presenting a design-oriented approach to analyze EBD–PA cointegration, wherein the EBD is leveraged as part of the PA’s matching network. In addition, this work explores the challenges of achieving simultaneous EBD–PA matching, to maximize power delivery to the antenna, and EBD–antenna matching, to ensure a return loss (RL) greater than 10 dB at the antenna port. As will be demonstrated, reciprocal network constraints for PA matching network, depending on the PA’s output impedance and optimal load, may lead to a suboptimal PA operation to meet these simultaneous matching requirements. The presented EBD is tuned using a programmable balancing network that achieves over 40-dB TX–RX isolation across more than 300-MHz bandwidth, with a simulated IIP<sub>3</sub> of +56 dBm while accommodating antenna impedance variations within a 1.22:1 VSWR across the 23–30-GHz band. In addition, a measured isolation exceeding 30 dB over the bandwidth of operation is achieved using a real antenna with a VSWR of up to 1.5:1. The designed PA delivers a simulated output power of +16.5 dBm when loaded by <inline-formula> <tex-math>${Z}_{Ltext {-Opt}}$ </tex-math></inline-formula> at 26 GHz in standalone operation. When integrated with the EBD using the proposed coil design methodology, the delivered power to the EBD’s TX port decreases by 1.3 dB to +15.2 dBm, reflecting the tradeoff associated with simultaneous EBD–PA and EBD–antenna matching. The simulated TX insertion loss (TXIL) of the EBD is 2.3–2.4 dB, and the measured power delivered to the antenna ranges from 11 to 12.9 dBm across the 23–30-GHz band. In the RX path comprising the EBD and LNA, a measured noise figure (NF) of <8.5>2</sup> (<inline-formula> <tex-math>$1.98times 1.19$ </tex-math></inline-formula> mm), inclusive of all pads.","PeriodicalId":13272,"journal":{"name":"IEEE Transactions on Microwave Theory and Techniques","volume":"73 12","pages":"10724-10743"},"PeriodicalIF":4.5,"publicationDate":"2025-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145778317","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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