Pub Date : 2025-11-04DOI: 10.1109/LAWP.2025.3629144
Donghua Zou;Weicong Chen;Wankai Tang;Jun Yan Dai;Qiang Cheng;Shi Jin
Accurate characterization of the reflection coefficient of reconfigurable intelligent surface (RIS) is crucial for the design and optimization of RIS-assisted communication systems. Conventional measurement methods often rely on specialized instruments, which are costly and bulky. In this letter, we propose a novel harmonic-based reflection coefficient measurement method that enables in-situ and low-cost measurement using standard software-defined radio platform. By applying time-varying square-wave control signals to the RIS, the proposed method can obtain the amplitude ratio and the phase difference between two reflection states through harmonic analysis of the reflected signal. A prototype system is developed and experimentally validated, demonstrating that the proposed method achieves comparable measurement results to that of conventional approaches while significantly reducing hardware complexity.
{"title":"Reflection Coefficient Measurement Method for Reconfigurable Intelligent Surface Based on Harmonic Analysis","authors":"Donghua Zou;Weicong Chen;Wankai Tang;Jun Yan Dai;Qiang Cheng;Shi Jin","doi":"10.1109/LAWP.2025.3629144","DOIUrl":"https://doi.org/10.1109/LAWP.2025.3629144","url":null,"abstract":"Accurate characterization of the reflection coefficient of reconfigurable intelligent surface (RIS) is crucial for the design and optimization of RIS-assisted communication systems. Conventional measurement methods often rely on specialized instruments, which are costly and bulky. In this letter, we propose a novel harmonic-based reflection coefficient measurement method that enables in-situ and low-cost measurement using standard software-defined radio platform. By applying time-varying square-wave control signals to the RIS, the proposed method can obtain the amplitude ratio and the phase difference between two reflection states through harmonic analysis of the reflected signal. A prototype system is developed and experimentally validated, demonstrating that the proposed method achieves comparable measurement results to that of conventional approaches while significantly reducing hardware complexity.","PeriodicalId":51059,"journal":{"name":"IEEE Antennas and Wireless Propagation Letters","volume":"25 1","pages":"433-437"},"PeriodicalIF":4.8,"publicationDate":"2025-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145915589","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Acoustically actuated antennas exploit mechanical resonance to achieve electrically small and on-chip implementation. However, these unique traits complicate the accurate characterization of their radiation performance. In this work, we systematically identify and quantify two dominant sources of extrinsic electromagnetic radiation in on-chip measurements: 1) substrate coupling that effectively extends the radiating aperture and 2) parasitic radiation from probes and cables. In typical acoustic antenna measurements, both effects can overestimate the measured gain by more than 10 dB, while leaving the resonance response largely unaffected. This behavior is distinct from that of conventional electrically small antennas. Through controlled experiments, we reveal that improper test conditions, including oversized substrates, probe feeding, near-field and nonanechoic environments, can cause radiation gain errors greater than 20 dB. Based on these findings, we develop and validate a standardized test protocol incorporating die-level isolation, ferrite bead loading, wire-bonded printed circuit board (PCB) feeding, and far-field anechoic measurements. These results reveal critical but previously overlooked artifacts in the characterization of acoustic antennas and establish a framework for their intrinsic evaluation.
{"title":"Accurate Radiation Evaluation of Electrically Small On-Chip Acoustically Actuated Antennas","authors":"Jianle Liu;Chenye Zhang;Kailin Li;Yahui Ji;Peiran Zhang;Dengfeng Ju;Yang Lu;Xianfeng Liang;Tianling Ren;Fan Yang;Tianxiang Nan","doi":"10.1109/LAWP.2025.3628935","DOIUrl":"https://doi.org/10.1109/LAWP.2025.3628935","url":null,"abstract":"Acoustically actuated antennas exploit mechanical resonance to achieve electrically small and on-chip implementation. However, these unique traits complicate the accurate characterization of their radiation performance. In this work, we systematically identify and quantify two dominant sources of extrinsic electromagnetic radiation in on-chip measurements: 1) substrate coupling that effectively extends the radiating aperture and 2) parasitic radiation from probes and cables. In typical acoustic antenna measurements, both effects can overestimate the measured gain by more than 10 dB, while leaving the resonance response largely unaffected. This behavior is distinct from that of conventional electrically small antennas. Through controlled experiments, we reveal that improper test conditions, including oversized substrates, probe feeding, near-field and nonanechoic environments, can cause radiation gain errors greater than 20 dB. Based on these findings, we develop and validate a standardized test protocol incorporating die-level isolation, ferrite bead loading, wire-bonded printed circuit board (PCB) feeding, and far-field anechoic measurements. These results reveal critical but previously overlooked artifacts in the characterization of acoustic antennas and establish a framework for their intrinsic evaluation.","PeriodicalId":51059,"journal":{"name":"IEEE Antennas and Wireless Propagation Letters","volume":"25 1","pages":"423-427"},"PeriodicalIF":4.8,"publicationDate":"2025-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145915572","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-04DOI: 10.1109/LAWP.2025.3628737
Rishi Mishra;A R Harish
A tri-band shared-aperture antenna array is proposed in this letter. Band-1 (3.76 GHz to 4.76 GHz) and Band-2 (5.20 GHz to –6.45 GHz) antennas are designed such that the structure of one band exhibits a surface-wave electromagnetic bandgap (SW-EBG) characteristic for the other band, thereby enhancing inter-element isolation when arranged in a triangular 2 × 4 shared array. Two heterogeneous Band-3 (14.75 GHz to 15.25 GHz) elements—a microstrip patch and a substrate-integrated waveguide (SIW) cavity slot antenna—are designed and integrated into the Band-1 and Band-2 antenna structures, respectively. Each unit cell of the Band-1 structure contains four Band-3 patches, while each Band-2 unit cell incorporates one Band-3 SIW slot antenna. A prototype of a 2 × 4 shared-aperture array consisting of Band-1 and Band-2 elements with 128 (only 1 × 8 populated for testing) Band-3 elements is fabricated and tested. Good agreement between simulated and measured results is observed. For the single element, the simulated –10 dB reflection bandwidth of 23.5%, 21.5%, and 3.4% is achieved with peak gains of 10.7 dBi, 9.2 dBi, and 5.5 dBi in Band-1, Band-2, and Band-3, respectively.
{"title":"Tri-Band Shared-Aperture Array With Improved Isolation Using Heterogeneous Elements and EBG Structures","authors":"Rishi Mishra;A R Harish","doi":"10.1109/LAWP.2025.3628737","DOIUrl":"https://doi.org/10.1109/LAWP.2025.3628737","url":null,"abstract":"A tri-band shared-aperture antenna array is proposed in this letter. Band-1 (3.76 GHz to 4.76 GHz) and Band-2 (5.20 GHz to –6.45 GHz) antennas are designed such that the structure of one band exhibits a surface-wave electromagnetic bandgap (SW-EBG) characteristic for the other band, thereby enhancing inter-element isolation when arranged in a triangular 2 × 4 shared array. Two heterogeneous Band-3 (14.75 GHz to 15.25 GHz) elements—a microstrip patch and a substrate-integrated waveguide (SIW) cavity slot antenna—are designed and integrated into the Band-1 and Band-2 antenna structures, respectively. Each unit cell of the Band-1 structure contains four Band-3 patches, while each Band-2 unit cell incorporates one Band-3 SIW slot antenna. A prototype of a 2 × 4 shared-aperture array consisting of Band-1 and Band-2 elements with 128 (only 1 × 8 populated for testing) Band-3 elements is fabricated and tested. Good agreement between simulated and measured results is observed. For the single element, the simulated –10 dB reflection bandwidth of 23.5%, 21.5%, and 3.4% is achieved with peak gains of 10.7 dBi, 9.2 dBi, and 5.5 dBi in Band-1, Band-2, and Band-3, respectively.","PeriodicalId":51059,"journal":{"name":"IEEE Antennas and Wireless Propagation Letters","volume":"25 1","pages":"413-417"},"PeriodicalIF":4.8,"publicationDate":"2025-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145915487","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this letter, a multibeam reflectarray antenna operating at 16 GHz is proposed. The feed antenna contains 10 p-i-n diodes and 5 ports. By changing the states of the p-i-n diodes and exciting the corresponding port, 15 beams can be obtained. To reduce the sidelobe levels (SLLs) of the beams and achieve the broader beam coverage range (BCR), the multiobjective particle swarm optimization method is introduced to optimize the reflection phase of the reflectarray. Then, the proposed reflectarray is simulated, fabricated and measured. The simulated SLL is below −9.95 dB, and the beam range is from −38.6° to 37.3°. The measured SLL is below −8.74 dB, and the beam range is from −31.5° to 30.6°.
{"title":"A Ku-Band Multibeam Reflectarray With 15 Beams Based on the Phase Center Reconfigurable Feed Antenna","authors":"Wenting Li;Chulou Yang;Yangpeng Liu;Yejun He;Long Zhang;Sai-Wai Wong;Steven Gao","doi":"10.1109/LAWP.2025.3628348","DOIUrl":"https://doi.org/10.1109/LAWP.2025.3628348","url":null,"abstract":"In this letter, a multibeam reflectarray antenna operating at 16 GHz is proposed. The feed antenna contains 10 p-i-n diodes and 5 ports. By changing the states of the p-i-n diodes and exciting the corresponding port, 15 beams can be obtained. To reduce the sidelobe levels (SLLs) of the beams and achieve the broader beam coverage range (BCR), the multiobjective particle swarm optimization method is introduced to optimize the reflection phase of the reflectarray. Then, the proposed reflectarray is simulated, fabricated and measured. The simulated SLL is below −9.95 dB, and the beam range is from −38.6° to 37.3°. The measured SLL is below −8.74 dB, and the beam range is from −31.5° to 30.6°.","PeriodicalId":51059,"journal":{"name":"IEEE Antennas and Wireless Propagation Letters","volume":"25 1","pages":"408-412"},"PeriodicalIF":4.8,"publicationDate":"2025-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145915550","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-31DOI: 10.1109/LAWP.2025.3627774
Chao Feng Ding;Yi Zeng;Zhen-Yuan Zhang;Ming Yu
This letter presents a compact, via-free single-layer filtering microstrip patch antenna realized through strategically etched slots and stubs. First, we analyze the theoretical conditions for generating radiation nulls in the antenna network. Beyond the fundamental TM10 modes, two additional TM10-like resonant modes are introduced to enhance the filtering order and create controllable radiation nulls, enabling a tailored band-pass frequency response. By leveraging these extra modes, both the number and positions of radiation nulls can be precisely tuned. The proposed design is thoroughly validated through simulation, fabrication, and measurement, demonstrating excellent agreement between theoretical predictions and experimental results.
{"title":"A Via-Free Single-Layer Filtering Patch Antenna Using Etched Slots and Stubs","authors":"Chao Feng Ding;Yi Zeng;Zhen-Yuan Zhang;Ming Yu","doi":"10.1109/LAWP.2025.3627774","DOIUrl":"https://doi.org/10.1109/LAWP.2025.3627774","url":null,"abstract":"This letter presents a compact, via-free single-layer filtering microstrip patch antenna realized through strategically etched slots and stubs. First, we analyze the theoretical conditions for generating radiation nulls in the antenna network. Beyond the fundamental TM<sub>10</sub> modes, two additional TM<sub>10</sub>-like resonant modes are introduced to enhance the filtering order and create controllable radiation nulls, enabling a tailored band-pass frequency response. By leveraging these extra modes, both the number and positions of radiation nulls can be precisely tuned. The proposed design is thoroughly validated through simulation, fabrication, and measurement, demonstrating excellent agreement between theoretical predictions and experimental results.","PeriodicalId":51059,"journal":{"name":"IEEE Antennas and Wireless Propagation Letters","volume":"25 1","pages":"399-402"},"PeriodicalIF":4.8,"publicationDate":"2025-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145915606","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-31DOI: 10.1109/LAWP.2025.3627595
Hamza Asif Khan;Yang Jiang
The potential use of transparent metasurfaces in an optical system has driven significant research interest in recent years. However, issues, such as insufficient flexibility and bandwidth, have limited its real-world implementation. This study introduces a flexible and optically transparent metasurface (FAOTM), which is designed and characterized to efficiently convert linear polarization incident waves to circular polarization reflected waves across a broad spectrum of frequencies. The meta-atom of an FAOTM consists of an indium-tin-oxide-based diagonal butterfly-shaped pattern on top of polydimethylsiloxane dielectric substrate along with polyethylene–terephthalate supportive layer. Within the frequency range of 18.4 GHz to 25.0 GHz for x- and y-polarizations, the numerical analysis demonstrates that the axial ratio is less than 3 dB, which corresponds to a fractional bandwidth of 30%. The bandwidth for linear-to-circular polarization conversion is maintained across the specified frequency range at an oblique incidence angle of 30$^{circ }$. In addition, to offer a deeper understanding of the polarization conversion mechanism, a comprehensive analysis is conducted through a combination of theoretical analysis, surface current distribution, and equivalent circuit modeling. Finally, a prototype with 25 × 25 units is fabricated and experimental test is carried out. The experimental results exhibited good agreement with the simulation outcomes, confirming the performance of the proposed design.
{"title":"Design and Experimental Validation of a Flexible and Optically Transparent Metasurface for Broadband Linear-to-Circular Polarization Conversion","authors":"Hamza Asif Khan;Yang Jiang","doi":"10.1109/LAWP.2025.3627595","DOIUrl":"https://doi.org/10.1109/LAWP.2025.3627595","url":null,"abstract":"The potential use of transparent metasurfaces in an optical system has driven significant research interest in recent years. However, issues, such as insufficient flexibility and bandwidth, have limited its real-world implementation. This study introduces a flexible and optically transparent metasurface (FAOTM), which is designed and characterized to efficiently convert linear polarization incident waves to circular polarization reflected waves across a broad spectrum of frequencies. The meta-atom of an FAOTM consists of an indium-tin-oxide-based diagonal butterfly-shaped pattern on top of polydimethylsiloxane dielectric substrate along with polyethylene–terephthalate supportive layer. Within the frequency range of 18.4 GHz to 25.0 GHz for <italic>x</i>- and <italic>y</i>-polarizations, the numerical analysis demonstrates that the axial ratio is less than 3 dB, which corresponds to a fractional bandwidth of 30%. The bandwidth for linear-to-circular polarization conversion is maintained across the specified frequency range at an oblique incidence angle of 30<inline-formula><tex-math>$^{circ }$</tex-math></inline-formula>. In addition, to offer a deeper understanding of the polarization conversion mechanism, a comprehensive analysis is conducted through a combination of theoretical analysis, surface current distribution, and equivalent circuit modeling. Finally, a prototype with 25 × 25 units is fabricated and experimental test is carried out. The experimental results exhibited good agreement with the simulation outcomes, confirming the performance of the proposed design.","PeriodicalId":51059,"journal":{"name":"IEEE Antennas and Wireless Propagation Letters","volume":"25 1","pages":"389-393"},"PeriodicalIF":4.8,"publicationDate":"2025-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145915549","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-31DOI: 10.1109/LAWP.2025.3627585
Ziqing Chu;Yingrui Yu;Zuping Qian;Wen Wu
In this letter, a compact Ku/Ka dual-band shared-aperture endfire beam-scanning antenna array is presented. The proposed shared-aperture array consists of a Ka-band half-mode substrate integrated waveguide (HSIW) frequency-scanning leaky-wave antenna and a Ku-band tapered radiating wedge phased array fed by substrate integrated coaxial line (SICL). Particularly, a pair of tapered radiating wedges, which function as radiators at two separate frequencies, are fed by multiple Γ-shaped probes and an open-ended HSIW at Ku band and Ka band, respectively, to realize full aperture reuse. Also, the Γ-shaped feeding probes function as periodic loading structures for Ka-band frequency-scanning leaky-wave array. Meanwhile, the feeding SICLs are embedded into the HSIW to realize a compact array footprint while not influencing the radiation performance at Ka band. Owing to the differences of electric-field distribution between the fundamental modes of HSIW and SICL, high isolation level can be achieved between two separate bands under the same polarization type. The proposed shared-aperture array enables producing frequency-scanning beams within ±17.5° ranging from 37.5 GHz to 40.5 GHz and phased-scanning radiation beams within ±45° at Ku band, which represents a promising candidate for multifunction wireless applications.
{"title":"A Ku/Ka Dual-Band Shared-Aperture Beam-Scanning Antenna Array With Efficient Aperture Utilization and High Isolation","authors":"Ziqing Chu;Yingrui Yu;Zuping Qian;Wen Wu","doi":"10.1109/LAWP.2025.3627585","DOIUrl":"https://doi.org/10.1109/LAWP.2025.3627585","url":null,"abstract":"In this letter, a compact Ku/Ka dual-band shared-aperture endfire beam-scanning antenna array is presented. The proposed shared-aperture array consists of a Ka-band half-mode substrate integrated waveguide (HSIW) frequency-scanning leaky-wave antenna and a Ku-band tapered radiating wedge phased array fed by substrate integrated coaxial line (SICL). Particularly, a pair of tapered radiating wedges, which function as radiators at two separate frequencies, are fed by multiple Γ-shaped probes and an open-ended HSIW at Ku band and Ka band, respectively, to realize full aperture reuse. Also, the Γ-shaped feeding probes function as periodic loading structures for Ka-band frequency-scanning leaky-wave array. Meanwhile, the feeding SICLs are embedded into the HSIW to realize a compact array footprint while not influencing the radiation performance at Ka band. Owing to the differences of electric-field distribution between the fundamental modes of HSIW and SICL, high isolation level can be achieved between two separate bands under the same polarization type. The proposed shared-aperture array enables producing frequency-scanning beams within ±17.5° ranging from 37.5 GHz to 40.5 GHz and phased-scanning radiation beams within ±45° at Ku band, which represents a promising candidate for multifunction wireless applications.","PeriodicalId":51059,"journal":{"name":"IEEE Antennas and Wireless Propagation Letters","volume":"25 1","pages":"384-388"},"PeriodicalIF":4.8,"publicationDate":"2025-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145915559","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-31DOI: 10.1109/LAWP.2025.3627405
Pei Gan;Yunyan Zhou;Gang Song;Chenglin Yang;WenWen Zhang;Yuxiang Zheng;Jun Li;Qidong Wang
This letter presents a tri-mode magneto-electric (ME) dipole antenna based on high-density-interconnect (HDI) technology, offering high integration capability and manufacturability for W-band applications. The proposed antenna achieves broadband operation through tri-mode excitation of electric and magnetic dipole resonances, ensuring stable radiation performance across the band. Two array prototypes are fabricated and tested: a 2 × 2 parallel-fed array, demonstrating a measured bandwidth of 37.1% (75 GHz to 109.2 GHz) and peak gain of 14.05 dBi; and a 1 × 8 series-fed array exhibits a measured gain of 14.83 dBi and a sidelobe level (SLL) of −15.78 dB at 77 GHz. This letter presents a promising pathway for scalable, broadband, and low SLL antenna-in-package integration at W band.
{"title":"A Tri-Mode Magneto-Electric Dipole Antenna Based on High-Density-Interconnect (HDI) Technology for W-Band Applications","authors":"Pei Gan;Yunyan Zhou;Gang Song;Chenglin Yang;WenWen Zhang;Yuxiang Zheng;Jun Li;Qidong Wang","doi":"10.1109/LAWP.2025.3627405","DOIUrl":"https://doi.org/10.1109/LAWP.2025.3627405","url":null,"abstract":"This letter presents a tri-mode magneto-electric (ME) dipole antenna based on high-density-interconnect (HDI) technology, offering high integration capability and manufacturability for W-band applications. The proposed antenna achieves broadband operation through tri-mode excitation of electric and magnetic dipole resonances, ensuring stable radiation performance across the band. Two array prototypes are fabricated and tested: a 2 × 2 parallel-fed array, demonstrating a measured bandwidth of 37.1% (75 GHz to 109.2 GHz) and peak gain of 14.05 dBi; and a 1 × 8 series-fed array exhibits a measured gain of 14.83 dBi and a sidelobe level (SLL) of −15.78 dB at 77 GHz. This letter presents a promising pathway for scalable, broadband, and low SLL antenna-in-package integration at W band.","PeriodicalId":51059,"journal":{"name":"IEEE Antennas and Wireless Propagation Letters","volume":"25 1","pages":"369-373"},"PeriodicalIF":4.8,"publicationDate":"2025-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145915488","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In this letter, we propose a new structure for liquid crystal reflectarray (LCRA) aimed at improving response time. In LCRA, liquid crystal (LC) serves as a phase-tunable material that can be continuously modulated by an external electric field. However, the inherently slow response time of LC remains a significant limitation for practical applications. To address this issue, we introduce a structure incorporating partition walls with vertical alignment films on the surface of the LCRA. This design induces an additional anchoring force on the LC layer, facilitating faster reorientation of LC molecules, which results in significant reduce of the response time. For validation, an LCRA prototype based on the proposed structure was fabricated and experimentally measured. The results demonstrate a substantial improvement in response performance, with the decay time reduced from 6.62 s to 0.73 s. It is believed that the proposed LCRA structure will be a promising candidate for future reflectarray applications.
{"title":"Response Time Improvement of Liquid Crystal Reflectarray Using Partition Wall Structure","authors":"Yuhao Shang;Hiroyasu Sato;Kai-Da Xu;Masakazu Nakatani;Yasuo Yamamoto;Hideo Fujikake;Qiang Chen","doi":"10.1109/LAWP.2025.3627639","DOIUrl":"https://doi.org/10.1109/LAWP.2025.3627639","url":null,"abstract":"In this letter, we propose a new structure for liquid crystal reflectarray (LCRA) aimed at improving response time. In LCRA, liquid crystal (LC) serves as a phase-tunable material that can be continuously modulated by an external electric field. However, the inherently slow response time of LC remains a significant limitation for practical applications. To address this issue, we introduce a structure incorporating partition walls with vertical alignment films on the surface of the LCRA. This design induces an additional anchoring force on the LC layer, facilitating faster reorientation of LC molecules, which results in significant reduce of the response time. For validation, an LCRA prototype based on the proposed structure was fabricated and experimentally measured. The results demonstrate a substantial improvement in response performance, with the decay time reduced from 6.62 s to 0.73 s. It is believed that the proposed LCRA structure will be a promising candidate for future reflectarray applications.","PeriodicalId":51059,"journal":{"name":"IEEE Antennas and Wireless Propagation Letters","volume":"25 1","pages":"394-398"},"PeriodicalIF":4.8,"publicationDate":"2025-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145915593","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-31DOI: 10.1109/LAWP.2025.3628048
Chao Qun Zhang;Li Ying Feng
Enhancing the gain of circularly polarized (CP) antennas while preserving axial ratio (AR) bandwidth is critical for advanced communication systems. Herein, we present a CP magnetoelectric (ME) dipole antenna augmented with a CP ME-dipole director to achieve improved gain without sacrificing AR bandwidth. Fabricated and tested prototypes show that incorporating the CP ME-dipole director increases the antenna’s average gain from 9.74 (simulated) to 11.04 dBic and achieves a measured 3 dB AR bandwidth of 45.54% (1.95 GHz to 3.1 GHz), closely aligning with simulation results. The proposed design also demonstrates wide impedance bandwidth and favorable radiation patterns with low back lobes. These results confirm the CP ME-dipole director’s effectiveness in enhancing antenna performance, making it highly suitable for long-distance and 5G communication applications.
{"title":"Gain Enhancement of ME-Dipole Antenna by Loading a CP ME-Dipole Director","authors":"Chao Qun Zhang;Li Ying Feng","doi":"10.1109/LAWP.2025.3628048","DOIUrl":"https://doi.org/10.1109/LAWP.2025.3628048","url":null,"abstract":"Enhancing the gain of circularly polarized (CP) antennas while preserving axial ratio (AR) bandwidth is critical for advanced communication systems. Herein, we present a CP magnetoelectric (ME) dipole antenna augmented with a CP ME-dipole director to achieve improved gain without sacrificing AR bandwidth. Fabricated and tested prototypes show that incorporating the CP ME-dipole director increases the antenna’s average gain from 9.74 (simulated) to 11.04 dBic and achieves a measured 3 dB AR bandwidth of 45.54% (1.95 GHz to 3.1 GHz), closely aligning with simulation results. The proposed design also demonstrates wide impedance bandwidth and favorable radiation patterns with low back lobes. These results confirm the CP ME-dipole director’s effectiveness in enhancing antenna performance, making it highly suitable for long-distance and 5G communication applications.","PeriodicalId":51059,"journal":{"name":"IEEE Antennas and Wireless Propagation Letters","volume":"25 1","pages":"403-407"},"PeriodicalIF":4.8,"publicationDate":"2025-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145915587","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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