Microwave and Optical Technology Letters最新文献

{"title":"A Low-Profile Diplexing Filtenna Based on Quarter-Mode Substrate Integrated Waveguide","authors":"Dong Yan,&nbsp;Yan-Gang Zhou,&nbsp;Kun-Zhi Hu,&nbsp;Dajiang Li,&nbsp;Zhiyuan Chen","doi":"10.1002/mop.70760","DOIUrl":"https://doi.org/10.1002/mop.70760","url":null,"abstract":"<div>\u0000 \u0000 <p>In this letter, a low-profile diplexing filtenna based on a quarter-mode substrate integrated waveguide (QMSIW) is presented. A cross-shaped slot is etched on the top of the circular substrate integrated waveguide (SIW) cavity, dividing it into four parts, each of which can function independently as a QMSIW resonator. Four metallic perturbation vias are loaded in the cavity to tune the impedance matching. To suppress the cross-polarization generated by the introduction of the cross-shaped slot, four pairs of metallic suppression vias are loaded around the edges of the cross-shaped slot. Finally, a rectangular feeding cavity with a complementary split-ring resonator (CSRR) are utilized to excite the circular SIW cavity, achieving enhanced impedance bandwidth and filtering performance. To validate the design method, a prototype of the diplexing filtenna was fabricated and measured. The measured results are in good agreement with the simulated ones, showing that the diplexing filtenna exhibits fractional impedance bandwidths of 6.8% (3.84–4.11 GHz) and 6.6% (4.8–5.13 GHz) for lower and upper passbands, respectively. The realized gain curves experience good filtering with peak realized gains of 4.69 and 5.11 dBi at the boresight direction, respectively.</p>\u0000 </div>","PeriodicalId":18562,"journal":{"name":"Microwave and Optical Technology Letters","volume":"68 9","pages":""},"PeriodicalIF":1.1,"publicationDate":"2026-09-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148942871","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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-Isolation Two-Port OLAF MIMO Antenna Using Inclined Slotted Decoupling for 5.8 GHz Industrial IoT Sensing and Wireless Monitoring","authors":"Janet Mercy V,&nbsp;Beno A","doi":"10.1002/mop.70779","DOIUrl":"https://doi.org/10.1002/mop.70779","url":null,"abstract":"<div>\u0000 \u0000 <p>A compact two-port Omega Loop Annular Fusion (OLAF) MIMO antenna operating at 5.8 GHz is developed for Industrial Internet of Things (IIoT) sensing and short-range wearable body-centric wireless applications in controlled environments. The antenna is built on a 25.9 × 29.7 × 1.8 mm polyethylene substrate (<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 \u0000 <mrow>\u0000 <msub>\u0000 <mi>ε</mi>\u0000 \u0000 <mi>r</mi>\u0000 </msub>\u0000 </mrow>\u0000 </mrow>\u0000 <annotation> ${varepsilon }_{r}$</annotation>\u0000 </semantics></math> = 2.25, tan <i>δ</i> = 0.001). The proposed design employs an omega-shaped radiating element integrated with an outer annular ring to achieve effective impedance matching. Additionally, a simple inclined slotted decoupling strip is introduced to mitigate coupling between the antenna radiators and improve port isolation without altering the ground plane. The fabricated antenna achieves a measured return loss bandwidth of 5.80–5.84 GHz, high isolation of 43.55 dB, a peak gain of 6.8 dBi, and a radiation efficiency of 96%. Furthermore, the antenna exhibits excellent MIMO performance with low envelope correlation, ideal diversity gain, negligible spectral capacity loss, and optimal active reflection characteristics. The measured and simulated results validate the proposed design, demonstrating its suitability for compact, reliable, and high-performance dedicated wireless links in the 5.8 GHz ISM band for Industrial IoT sensing and wearable body-centric wireless applications in controlled environments.</p>\u0000 </div>","PeriodicalId":18562,"journal":{"name":"Microwave and Optical Technology Letters","volume":"68 9","pages":""},"PeriodicalIF":1.1,"publicationDate":"2026-09-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148942625","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Broadband Co-Polarized Magneto-Electric Dipole Antenna With High Isolation for In-Band Full-Duplex Systems","authors":"Yan-Ming Ren,&nbsp;Rui Wu,&nbsp;Fu-Chang Chen","doi":"10.1002/mop.70780","DOIUrl":"https://doi.org/10.1002/mop.70780","url":null,"abstract":"<div>\u0000 \u0000 <p>A broadband co-polarized magneto-electric (ME) dipole antenna with high isolation is proposed for in-band full-duplex (IBFD) applications. To suppress strong self-interference (SI) between the collocated transmitter (Tx) and receiver (Rx), a decoupling mechanism based on common-mode (CM) and differential-mode (DM) impedance adjusting is analyzed and implemented. The design features two partially overlapped ME dipoles loaded with specific decoupling patch and decoupling loop to cancel mutual coupling. A prototype was fabricated and measured, demonstrating impedance bandwidth of 41.7% (1.9–2.9 GHz). Across this band, the port-to-port isolation exceeds 19 dB, while within the 2.2–2.9 GHz sub-band, it is significantly enhanced to over 38 dB, with a peak isolation of 50 dB. Moreover, the antenna exhibits consistent stable Tx/Rx broadside radiation patterns and a peak realized gain of 6.3 dBi. These features make the proposed design a promising antenna domain of compact IBFD systems.</p>\u0000 </div>","PeriodicalId":18562,"journal":{"name":"Microwave and Optical Technology Letters","volume":"68 9","pages":""},"PeriodicalIF":1.1,"publicationDate":"2026-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148942716","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Surrogate Model-Assisted Grey Wolf Algorithm for Multi-Objective Antenna Optimization Design","authors":"Yukun Fu,&nbsp;Zhengqi Li,&nbsp;Junxia Fu,&nbsp;Juan Xu","doi":"10.1002/mop.70777","DOIUrl":"https://doi.org/10.1002/mop.70777","url":null,"abstract":"<div>\u0000 \u0000 <p>Antenna structures usually involve many strongly coupled geometric parameters. Directly embedding full-wave simulations into swarm-intelligence optimization leads to high computational cost and slow convergence, while making it difficult to balance conflicting objectives such as impedance bandwidth, circular-polarization axial ratio, and gain. To address this issue, this paper proposes a surrogate-model-assisted improved multi-objective grey wolf optimization framework. The framework takes “structural parameters + frequency” as inputs to rapidly predict the swept-frequency responses of |S11|, axial ratio (AR), and realized gain (Gain). By adaptively updating the convergence factor and introducing probabilistic mutation perturbations after position updates to enhance global exploration and avoid premature convergence, an improved grey wolf optimization strategy (IGWO) is constructed. On this basis, the method is extended to a multi-objective framework by introducing an external archive to store non-dominated solutions and combining grid crowding with a leader-selection mechanism to maintain diversity, thereby obtaining a more evenly distributed Pareto-optimal solution set. Using a millimeter-wave circularly polarized magnetoelectric dipole antenna element as an example, the proposed method significantly reduces the number of full-wave simulations while improving impedance bandwidth and axial ratio bandwidth, achieving comprehensive optimization of high gain, demonstrating the effectiveness and practical applicability of the framework.</p>\u0000 </div>","PeriodicalId":18562,"journal":{"name":"Microwave and Optical Technology Letters","volume":"68 9","pages":""},"PeriodicalIF":1.1,"publicationDate":"2026-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148942511","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Design and Performance Evaluation of a Graphene-Based Meandered Slotted Terahertz Antenna for Ultra-High-Speed 6G and Terahertz Wireless Personal Area Network Applications","authors":"KoteswaraRao K,&nbsp;I. Sharath Chandra","doi":"10.1002/mop.70768","DOIUrl":"https://doi.org/10.1002/mop.70768","url":null,"abstract":"<div>\u0000 \u0000 <p>Graphene-based terahertz (THz) antennas have emerged as promising candidates for 6G and Terahertz Wireless Personal Area Network (TWPAN) applications owing to their compact size, high data transmission capability, and wide operating bandwidth. This paper presents the design and performance evaluation of a graphene-based meandered-slotted terahertz multiple-input multiple-output (MIMO) antenna fabricated on a polyimide substrate for compact integration and enhanced electromagnetic performance. The proposed antenna exhibits multiple resonant frequencies, a reflection coefficient below −32 dB, isolation better than −40 dB (reaching a minimum of −65 dB), and an impedance bandwidth of 88.14%. The diversity performance is validated through an envelope correlation coefficient (ECC) below 0.0001, a diversity gain (DG) of approximately 10.03 dB, a channel capacity loss (CCL) below 0.1 bps/Hz, and stable mean effective gain (MEG) characteristics. A parametric analysis is also performed to evaluate the influence of substrate thickness on antenna performance, demonstrating the structural robustness of the proposed design. Simulation results confirm that the proposed antenna provides excellent impedance matching, high isolation, wideband operation, and reliable diversity characteristics, making it a promising candidate for future 6G and terahertz wireless communication systems.</p>\u0000 </div>","PeriodicalId":18562,"journal":{"name":"Microwave and Optical Technology Letters","volume":"68 9","pages":""},"PeriodicalIF":1.1,"publicationDate":"2026-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148942202","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An All-Port-Reflectionless Wideband Filtering Power Divider With High Selectivity and High Stopband Suppression","authors":"Junkuan Wang,&nbsp;Zhongbao Wang,&nbsp;Qiuying Zhang,&nbsp;Hongmei Liu","doi":"10.1002/mop.70769","DOIUrl":"https://doi.org/10.1002/mop.70769","url":null,"abstract":"<div>\u0000 \u0000 <p>This paper presents an all-port-reflectionless wideband filtering power divider (FPD) with high selectivity and high stopband suppression. The proposed structure consists of two pairs of coupled-line sections (CLs), an input absorptive stub, a T-shaped network, and a novel composite absorptive network. The CLs determine the passband characteristics, while the input absorptive stub and the T<i>-</i>shaped network are used to improve the input-port matching performance and the isolation between the output ports. The composite absorptive network can not only effectively absorb the out-of-band reflected energy at the output ports, but also introduce transmission zeros on both sides of the passband, thereby improving frequency selectivity and stopband suppression. A theoretical analysis model of the proposed FPD is established based on the voltage-current node method, and the key electrical parameters of the proposed FPD are discussed in detail. To verify the effectiveness of the design method, a microstrip FPD prototype centered at <i>f</i>₀ = 2.45 GHz is designed, fabricated, and measured. The measured results show that the proposed FPD exhibits a 3 dB fractional bandwidth of 68.6%, an input-port 10 dB reflectionless bandwidth of 260%, an output-port 10 dB reflectionless bandwidth of 225%, an in-band isolation better than 20 dB, stopband suppression better than 27 dB up to 2.6<i>f</i>₀, and the shape factor of 1.21. Compared with previously reported FPDs, the proposed design provides a solution by simultaneously achieving all-port-reflectionless operation, high selectivity, and high stopband suppression within a single circuit topology.</p>\u0000 </div>","PeriodicalId":18562,"journal":{"name":"Microwave and Optical Technology Letters","volume":"68 9","pages":""},"PeriodicalIF":1.1,"publicationDate":"2026-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148942398","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Design of a Ku-Band Filtenna With a Modified Slot Structure for Satellite Communication Applications","authors":"Jannet Gnana Shirley Joseph Paul,&nbsp;Periasamy Paapampalayam Shanmugam,&nbsp;Anitha Periasamy,&nbsp;Veeramani Rajumani","doi":"10.1002/mop.70776","DOIUrl":"https://doi.org/10.1002/mop.70776","url":null,"abstract":"<div>\u0000 \u0000 <p>A Filtenna, also known as a Filter-Antenna Module, is a ground-breaking hybrid device that combines the functions of a filter and an antenna in a single structure. The filtering function is realized through the effective reactive behavior of the integrated parallel-coupled dual-line bandpass filter, which provides frequency selectivity while enabling the antenna to radiate at the desired frequencies. The presented design is an ultra-wideband antenna with an inset feeding network and a dual-line coupling structure that serves as a bandpass filter structure. This construction is augmented with a defected ground structure that uses a shaped slot designed to support narrowband applications, namely Ku-band uplink and downlink satellite communications. This is because the dual-line coupling structure provides stronger coupling between closely spaced lines, enabling precise frequency control. The filtenna is built on a Rogers RT/Duroid 3010 substrate with a thickness of 0.635 mm and a dielectric constant ξr of 3.4, giving it excellent performance and reliability. High-frequency structure simulator software was used to optimize the design and achieve the required operational characteristics. The simulation is confirmed by experimental results that demonstrate that the filtenna is able to work at 11.5 GHz and 14 GHz, which reaches a reflection coefficient (<span></span><math>\u0000 <semantics>\u0000 <mrow>\u0000 \u0000 <mrow>\u0000 <msub>\u0000 <mi>S</mi>\u0000 \u0000 <mn>11</mn>\u0000 </msub>\u0000 </mrow>\u0000 </mrow>\u0000 <annotation> ${S}_{11}$</annotation>\u0000 </semantics></math>) of below −20 dB. The gain values observed are 4.18 dB and 3.59 dB at these respective frequencies, which is good performance. The test was conducted in an anechoic chamber and using a network analyzer (Agilent N5247A: A.09.90.02) to get the correct electromagnetic measurements. The proposed design is compact, with physical dimensions of 20.56 × 16.98 mm (total built-up area of less than 348 mm²), making it highly advantageous for space-constrained Ku-band satellite communication applications, making it highly advantageous for space-constrained Ku-band satellite communication applications. This innovative approach not only reduces system complexity by merging filtering and radiating functions but also enhances overall efficiency, setting a benchmark for future antenna-filter integration designs.</p>\u0000 </div>","PeriodicalId":18562,"journal":{"name":"Microwave and Optical Technology Letters","volume":"68 9","pages":""},"PeriodicalIF":1.1,"publicationDate":"2026-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148943532","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Generative Adversarial Networks for Designing Single-Layer Frequency Selective Surfaces With Ultra-Wideband Parasitic Passband Rejection Characteristics","authors":"Fu-Long Jin,&nbsp;Hao-Chen Guo,&nbsp;Wei-Wei Xu,&nbsp;Xiao Ding","doi":"10.1002/mop.70766","DOIUrl":"https://doi.org/10.1002/mop.70766","url":null,"abstract":"<div>\u0000 \u0000 <p>Parasitic passband rejection has always been a significant issue in the design of frequency selective surfaces (FSS), especially for bandpass-type FSS that require ultra-wideband cutoff characteristics. Conventional suppression methods, such as multilayer structures and miniaturization, can effectively suppress parasitic passbands. However, they are difficult to design, expensive to manufacture, and most importantly, their out-of-band suppression bandwidth is insufficient. To address these problems, an FSS with ultra-wideband parasitic passband suppression effect using a single-layer structure is proposed in this manuscript. First, the Wasserstein Divergence Generative Adversarial Network (WGAN-div) is used to find various FSS units in the multi-solution mapping domain. These FSS units generally have the same principal resonant frequency but different metal patterns. Then, an array of these units is created under the out-of-band energy homogenization constraint. Finally, the measurement results further demonstrate that the designed FSS operating at 3.5 GHz has a good out-of-band rejection beyond the operating frequency. In addition to the single-layer structure, the proposed method also features cheap cost and low insertion loss.</p>\u0000 </div>","PeriodicalId":18562,"journal":{"name":"Microwave and Optical Technology Letters","volume":"68 9","pages":""},"PeriodicalIF":1.1,"publicationDate":"2026-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148943531","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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-Tunable Absorptive Bandpass Filter Controlled by TD3-Based Reinforcement Learning","authors":"Young-Ho Cho,&nbsp;Juhee Jung,&nbsp;Sang-Min Han","doi":"10.1002/mop.70773","DOIUrl":"https://doi.org/10.1002/mop.70773","url":null,"abstract":"<div>\u0000 \u0000 \u0000 <section>\u0000 <p>This letter presents a tunable absorptive bandpass filter controlled by the twin delayed deep deterministic policy gradient (TD3) reinforcement learning algorithm. The TD3 algorithm effectively handles continuous action spaces and stabilizes learning, thereby enabling the continuous tuning of the center frequency and achieving a satisfactory absorptive response. Further, a customized reward function and state structure tailored for tunable absorptive filter are designed for optimizing transfer and reflection responses for the filter. A measurement-based training method is employed to reduce the training time of the TD3 agent. The proposed method successfully tunes the filter over the frequency range of 0.8–1.2 GHz, which achieves a return loss characteristic better than 10.3 dB across the 0.42–1.6 GHz. To the best of our knowledge, this work represents the first application of the TD3 algorithm to tunable absorptive filter control.</p>\u0000 </section>\u0000 </div>","PeriodicalId":18562,"journal":{"name":"Microwave and Optical Technology Letters","volume":"68 9","pages":""},"PeriodicalIF":1.1,"publicationDate":"2026-08-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148943704","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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 of Input Sensitivity and Signal-to-Noise Ratio Characteristics of a Broadband Frequency Divider","authors":"Zengshuang Wang,&nbsp;Xuan Li,&nbsp;Nengxu Zhu,&nbsp;Zenglong Zhao,&nbsp;Yiting Zhang,&nbsp;Keping Wang,&nbsp;Fanyi Meng","doi":"10.1002/mop.70775","DOIUrl":"https://doi.org/10.1002/mop.70775","url":null,"abstract":"<div>\u0000 \u0000 <p>This paper systematically investigates the input-sensitivity characteristics of a frequency divider under broadband input conditions and introduces input signal-to-noise ratio (SNR) as an additional operating constraint. Through theoretical modeling and experimental verification, the relationships among input sensitivity, noise floor, equivalent input noise integration bandwidth, equivalent input-referred noise figure, and SNR are established, clarifying how these quantities jointly constrain divider operation. The technical contribution is to extend the conventional two-dimensional frequency–power sensitivity window by treating input SNR as a third constraint that explains noise-induced division failure under broadband input conditions. To enhance the signal-processing capability of the divider, an improved two-stage buffer amplifier is proposed to strengthen weak-signal amplification and waveform shaping. A broadband divide-by-four frequency-divider chip was fabricated and verified using heterojunction bipolar transistor (HBT) technology. Under a +5 V supply, the divider consumes 95 mA, operates from 0.2 to 12 GHz, and exhibits an input-sensitivity range of −15 to 10 dBm over 1–11 GHz. Under the adopted 8–12 GHz broadband input-noise test condition, stable frequency division requires an input SNR of no less than approximately 10 dB. The planar die dimensions are 1.2 × 0.8 mm. This study provides a theoretical and practical basis for the design and optimization of broadband frequency dividers.</p></div>","PeriodicalId":18562,"journal":{"name":"Microwave and Optical Technology Letters","volume":"68 9","pages":""},"PeriodicalIF":1.1,"publicationDate":"2026-08-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148943397","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}