Ultra-wideband radar technology (UWB) has demonstrated its vital role through various applications in surveillance, search and rescue, health monitoring, and the military. Unlike conventional radars, UWB radars use high-frequency, wide-bandwidth pulses, enabling long-range detection and penetrating obstacles. This work presents an in-depth review of UWB radar systems for recognizing human activities in a room and through-the-wall (TTW) with other diverse applications. After briefly discussing different UWB radar working principles and architectures, the study explores their role in various TTW applications in real-world scenarios. An extensive performance comparison of the legacy studies is presented, focusing on detection tools, signal processing, and imaging algorithms. The discussion includes an analysis of the integration of machine learning models. The primary focus is on the detection, movement, monitoring of vital signs, and nonhuman classifications in the context of Through-The-Wall (TTW) scenarios. This study contributes to a better understanding of evolving technology capabilities by integrating artificial intelligence (AI) and robotics to automate and precisely locate the target in various scenarios. Furthermore, the discussion includes the impact of UWB technology on society, future industry trends, the commercial landscape, and ethical issues to understand and future research.
{"title":"Through-the-Wall Human Activity Recognition Using Radar Technologies: A Review","authors":"Jawad Yousaf;Satanai Yakoub;Sara Karkanawi;Taimur Hassan;Eqab Almajali;Huma Zia;Mohammed Ghazal","doi":"10.1109/OJAP.2024.3459045","DOIUrl":"10.1109/OJAP.2024.3459045","url":null,"abstract":"Ultra-wideband radar technology (UWB) has demonstrated its vital role through various applications in surveillance, search and rescue, health monitoring, and the military. Unlike conventional radars, UWB radars use high-frequency, wide-bandwidth pulses, enabling long-range detection and penetrating obstacles. This work presents an in-depth review of UWB radar systems for recognizing human activities in a room and through-the-wall (TTW) with other diverse applications. After briefly discussing different UWB radar working principles and architectures, the study explores their role in various TTW applications in real-world scenarios. An extensive performance comparison of the legacy studies is presented, focusing on detection tools, signal processing, and imaging algorithms. The discussion includes an analysis of the integration of machine learning models. The primary focus is on the detection, movement, monitoring of vital signs, and nonhuman classifications in the context of Through-The-Wall (TTW) scenarios. This study contributes to a better understanding of evolving technology capabilities by integrating artificial intelligence (AI) and robotics to automate and precisely locate the target in various scenarios. Furthermore, the discussion includes the impact of UWB technology on society, future industry trends, the commercial landscape, and ethical issues to understand and future research.","PeriodicalId":34267,"journal":{"name":"IEEE Open Journal of Antennas and Propagation","volume":"5 6","pages":"1815-1837"},"PeriodicalIF":3.5,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10679186","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142176041","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-12DOI: 10.1109/OJAP.2024.3456252
Abubakar Muhammad Sadiq;Minglve Liu;Xiao Zhang;Yu Luo;Yan Chen;Kaixue Ma
This article presents a mechanically frequency-reconfigurable monopole antenna and array that offers a wide tuning range, gain enhancement, and stable beamwidth. The monopole is positioned above a large reflector plate to achieve unidirectional radiation and increased gain. By adjusting the height between the monopole and reflector plate at λ/4 according to resonant frequencies, the frequency band and gain stability can be achieved. A single-motor controlled mechanical system enables the reconfiguration of resonant frequencies and gain enhancement. Measured results demonstrate that the frequency can be adjusted from 1.17 to 3.08 GHz (basic mode) with a relative bandwidth of 89% for a single monopole over the reflector. In the tuning frequency band, the gain and radiation efficiency are 7.51±0.88 dBi and 91.9±6%, respectively. To further enhance and stabilize the gain, a method is proposed and implemented in the array application. An advanced single-motor controlled mechanical system is designed to simultaneously adjust the resonant frequencies, height between the monopole and reflector plate, and inter-distance between the elements. Measured results show that the frequency can be adjusted from 1.15 to 3.0 GHz with a relative bandwidth of 86%. The achieved gain is 11.81±0.38 dBi, and the radiation efficiency is 89.9±8.2% at the basic mode. Additionally, the 3 dB beamwidth in the reconfigured band is 61.5o±6.5o and 39.5o±5.5o for E-planes and H-planes, respectively, indicating stable radiation patterns.
{"title":"Single-Motor Controlled Mechanically Frequency Reconfigurable Unidirectional Antenna Array With Stable Radiation Patterns","authors":"Abubakar Muhammad Sadiq;Minglve Liu;Xiao Zhang;Yu Luo;Yan Chen;Kaixue Ma","doi":"10.1109/OJAP.2024.3456252","DOIUrl":"10.1109/OJAP.2024.3456252","url":null,"abstract":"This article presents a mechanically frequency-reconfigurable monopole antenna and array that offers a wide tuning range, gain enhancement, and stable beamwidth. The monopole is positioned above a large reflector plate to achieve unidirectional radiation and increased gain. By adjusting the height between the monopole and reflector plate at λ/4 according to resonant frequencies, the frequency band and gain stability can be achieved. A single-motor controlled mechanical system enables the reconfiguration of resonant frequencies and gain enhancement. Measured results demonstrate that the frequency can be adjusted from 1.17 to 3.08 GHz (basic mode) with a relative bandwidth of 89% for a single monopole over the reflector. In the tuning frequency band, the gain and radiation efficiency are 7.51±0.88 dBi and 91.9±6%, respectively. To further enhance and stabilize the gain, a method is proposed and implemented in the array application. An advanced single-motor controlled mechanical system is designed to simultaneously adjust the resonant frequencies, height between the monopole and reflector plate, and inter-distance between the elements. Measured results show that the frequency can be adjusted from 1.15 to 3.0 GHz with a relative bandwidth of 86%. The achieved gain is 11.81±0.38 dBi, and the radiation efficiency is 89.9±8.2% at the basic mode. Additionally, the 3 dB beamwidth in the reconfigured band is 61.5o±6.5o and 39.5o±5.5o for E-planes and H-planes, respectively, indicating stable radiation patterns.","PeriodicalId":34267,"journal":{"name":"IEEE Open Journal of Antennas and Propagation","volume":"5 6","pages":"1773-1785"},"PeriodicalIF":3.5,"publicationDate":"2024-09-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10679160","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142176039","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-11DOI: 10.1109/OJAP.2024.3457989
Lauri Vähä-Savo;Lorenzo Veggi;Enrico M. Vitucci;Clemens Icheln;Vittorio Degli-Esposti;Katsuyuki Haneda
An analytical model for an antenna-embedded wall, also called signal-transmissive wall, is presented in this work. In the signal-transmissive wall, multiple antenna elements are distributed periodically on both wall sides, and connected back-to-back through coaxial cables. Numerical full-wave simulations of the signal-transmissive wall are computationally demanding due to the fine meshes required in the cables while having an electrically large wall size. Therefore the simulations above 8 GHz are not feasible even with a powerful cluster computer of the authors’ research site. The analytical model is an attractive alternative to the full-wave simulation of the wall, which combines the individual transmission characteristics of the bare wall, realized gains of antenna elements and cable losses. The analytical model accurately reproduces the full-wave simulated transmission coefficient of the signal-transmissive wall up to 8 GHz for arbitrary polarizations and incident angles of a plane wave. The model therefore allows analysis of the signal-transmissive wall beyond 8 GHz, showing more than 70 dB reduction of the transmission loss at 30 GHz compared to a bare wall.
{"title":"Analytical Characterization of a Transmission Loss of an Antenna-Embedded Wall","authors":"Lauri Vähä-Savo;Lorenzo Veggi;Enrico M. Vitucci;Clemens Icheln;Vittorio Degli-Esposti;Katsuyuki Haneda","doi":"10.1109/OJAP.2024.3457989","DOIUrl":"10.1109/OJAP.2024.3457989","url":null,"abstract":"An analytical model for an antenna-embedded wall, also called signal-transmissive wall, is presented in this work. In the signal-transmissive wall, multiple antenna elements are distributed periodically on both wall sides, and connected back-to-back through coaxial cables. Numerical full-wave simulations of the signal-transmissive wall are computationally demanding due to the fine meshes required in the cables while having an electrically large wall size. Therefore the simulations above 8 GHz are not feasible even with a powerful cluster computer of the authors’ research site. The analytical model is an attractive alternative to the full-wave simulation of the wall, which combines the individual transmission characteristics of the bare wall, realized gains of antenna elements and cable losses. The analytical model accurately reproduces the full-wave simulated transmission coefficient of the signal-transmissive wall up to 8 GHz for arbitrary polarizations and incident angles of a plane wave. The model therefore allows analysis of the signal-transmissive wall beyond 8 GHz, showing more than 70 dB reduction of the transmission loss at 30 GHz compared to a bare wall.","PeriodicalId":34267,"journal":{"name":"IEEE Open Journal of Antennas and Propagation","volume":"5 6","pages":"1765-1772"},"PeriodicalIF":3.5,"publicationDate":"2024-09-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10677548","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142176048","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-06DOI: 10.1109/OJAP.2024.3455421
Miguel Poveda-García;Alejandro Gil-Martínez;Astrid Algaba-Brazález;David Cañete-Rebenaque;José Luis Gómez-Tornero
The efficient series connection of planar leaky-wave antennas (LWA) to obtain directive frequency beam scanning, is proposed in this paper. Conditions for the proper performance are here derived, showing that the distance between antennas must be minimized while optimizing the phase shift introduced by the interconnection. Consequently, the methodology to design the transition is presented by an example using SMA connectors and a meander coaxial cable. Such series arrangement is useful to overcome the restricted directivity of planar LWAs in the UHF band due to limited PCB standard manufacturing sizes, while optimizing the radiation efficiency. The presented theory is validated with practical design examples of microstrip LWA arrays operating in the 900 MHz UHF band. Also, the frequency-beam scanning behaviour of the series-fed LWA array is analysed, demonstrating good performance when the proposed design conditions are satisfied, compared to a non-optimized design which can lead to destructive interference in the desired scanning directions.
{"title":"Series Arrangement Technique for Highly-Directive PCB Leaky-Wave Antennas With Application to RFID UHF Frequency Scanning Systems","authors":"Miguel Poveda-García;Alejandro Gil-Martínez;Astrid Algaba-Brazález;David Cañete-Rebenaque;José Luis Gómez-Tornero","doi":"10.1109/OJAP.2024.3455421","DOIUrl":"10.1109/OJAP.2024.3455421","url":null,"abstract":"The efficient series connection of planar leaky-wave antennas (LWA) to obtain directive frequency beam scanning, is proposed in this paper. Conditions for the proper performance are here derived, showing that the distance between antennas must be minimized while optimizing the phase shift introduced by the interconnection. Consequently, the methodology to design the transition is presented by an example using SMA connectors and a meander coaxial cable. Such series arrangement is useful to overcome the restricted directivity of planar LWAs in the UHF band due to limited PCB standard manufacturing sizes, while optimizing the radiation efficiency. The presented theory is validated with practical design examples of microstrip LWA arrays operating in the 900 MHz UHF band. Also, the frequency-beam scanning behaviour of the series-fed LWA array is analysed, demonstrating good performance when the proposed design conditions are satisfied, compared to a non-optimized design which can lead to destructive interference in the desired scanning directions.","PeriodicalId":34267,"journal":{"name":"IEEE Open Journal of Antennas and Propagation","volume":"5 5","pages":"1193-1208"},"PeriodicalIF":3.5,"publicationDate":"2024-09-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10668830","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142176042","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-05DOI: 10.1109/OJAP.2024.3454827
Shi Sun;Meng Wang;Zhang Wen Cheng;Tie Jun Cui;Hui Feng Ma
Previously proposed array antennas with low side-lobe level (SLL) based on amplitudephase metasurface inevitably result in high cross-polarization level (CPL) due to amplitude modulation is achieved by transforming some primary energy to the cross-polarization. This paper proposes a dualband circularly-polarized (CP) transmitarray antenna (TA) with simultaneous low SLL and CPL. The proposed antenna is based on a metasurface with independent amplitude and phase control at dual-band. The element of metasurface consists of dual-band receiver-transmitter (Rx-Tx) structures constructing CP receiving patches and transmitting patches. The amplitude and phase modulations at each band can be achieved dependently by adjusting the impedance-matching characteristics and the rotation angles of the Tx patches, respectively. By applying amplitude-phase modulation at dual-band, the antenna can achieve high directivity, low SLL and CPL simultaneously. Experimental results are in good accordance with the simulation ones, demonstrating that the designed low-side-lobe antenna realizes gains of 24.2 dBic and 25.2 dBic, CPLs of -32.2 dB and -26.6 dB, SLLs of -23.2 dB and -24 dB at 12 GHz and 15 GHz, respectively. The proposed TA shows good SLL and CPL performances at dual-band for dual-CP, which presents great application potential in two-way satellite communication systems with limited volume and space.
以前提出的基于振幅相元面的低侧叶电平（SLL）阵列天线不可避免地会导致高交叉极化电平（CPL），这是因为振幅调制是通过将一些主能量转化为交叉极化来实现的。本文提出了一种同时具有低 SLL 和低 CPL 的双频圆极化（CP）发射天线（TA）。所提议的天线基于双频独立振幅和相位控制的元面。元面元件由双频接收器-发射器（Rx-Tx）结构组成，构建了 CP 接收贴片和发射贴片。每个频段的振幅和相位调制可分别通过调整 Tx 补丁的阻抗匹配特性和旋转角度来实现。通过在双波段应用幅相调制，天线可同时实现高指向性、低 SLL 和 CPL。实验结果与仿真结果相符，表明所设计的低侧叶天线在 12 GHz 和 15 GHz 频率下分别实现了 24.2 dBic 和 25.2 dBic 增益、-32.2 dB 和 -26.6 dB CPL、-23.2 dB 和 -24 dB SLL。所提出的 TA 在双 CP 的双频上具有良好的 SLL 和 CPL 性能，在体积和空间有限的双向卫星通信系统中具有巨大的应用潜力。
{"title":"A Dual-Band Circularly-Polarized Transmitarray Antenna With Simultaneous Low Side-Lobe and Cross-Polarization Level","authors":"Shi Sun;Meng Wang;Zhang Wen Cheng;Tie Jun Cui;Hui Feng Ma","doi":"10.1109/OJAP.2024.3454827","DOIUrl":"10.1109/OJAP.2024.3454827","url":null,"abstract":"Previously proposed array antennas with low side-lobe level (SLL) based on amplitudephase metasurface inevitably result in high cross-polarization level (CPL) due to amplitude modulation is achieved by transforming some primary energy to the cross-polarization. This paper proposes a dualband circularly-polarized (CP) transmitarray antenna (TA) with simultaneous low SLL and CPL. The proposed antenna is based on a metasurface with independent amplitude and phase control at dual-band. The element of metasurface consists of dual-band receiver-transmitter (Rx-Tx) structures constructing CP receiving patches and transmitting patches. The amplitude and phase modulations at each band can be achieved dependently by adjusting the impedance-matching characteristics and the rotation angles of the Tx patches, respectively. By applying amplitude-phase modulation at dual-band, the antenna can achieve high directivity, low SLL and CPL simultaneously. Experimental results are in good accordance with the simulation ones, demonstrating that the designed low-side-lobe antenna realizes gains of 24.2 dBic and 25.2 dBic, CPLs of -32.2 dB and -26.6 dB, SLLs of -23.2 dB and -24 dB at 12 GHz and 15 GHz, respectively. The proposed TA shows good SLL and CPL performances at dual-band for dual-CP, which presents great application potential in two-way satellite communication systems with limited volume and space.","PeriodicalId":34267,"journal":{"name":"IEEE Open Journal of Antennas and Propagation","volume":"5 6","pages":"1758-1764"},"PeriodicalIF":3.5,"publicationDate":"2024-09-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10666860","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142176043","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-04DOI: 10.1109/OJAP.2024.3454330
Jia-Xiang Hao;Hui-Dong Li;Lei Zhu
This article proposes a design method for a circularly-polarized (CP) antenna, which is realized by using coupling effects. Initially, the desired electric(magnetic) coupling between two identical $lambda$ /4 short-circuited microstrip line (MS-L) resonators can be generated when the short-circuited (opencircuited) ends of the resonators are in close proximity to each other. Besides, an orthogonal arrangement in space for these two resonators has been adopted to yield two orthogonal linearly-polarized (LP) waves. Therefore, a desired CP rotation can be achieved by choosing corresponding coupling types. Meanwhile, two equivalent circuit models are established and analyzed to deduce the formulas of the mutual inductance and mutual capacitance for the desired CP radiation. Afterwards, a binary array consisting of a magnetically coupled (MC) pair of resonators and an electrically coupled (EC) pair of resonators is proposed for expanding the axial ratio bandwidth (ARBW) and enhancing peak gain. Finally, a right-handed circularlypolarized (RHCP) antenna with magnetic coupling, a left-handed circularly-polarized (LHCP) antenna with electric coupling and a binary array are fabricated and tested. And an excellent agreement is validated between the experiment and simulation results. The measured results show that the binary array achieves a maximum gain of 5 dBic within its measured ARBW range of 3.535 – 3.615 GHz. In contrast, the single pairs (EC or MC pair) exhibit a gain of 3 dBic. Additionally, the array demonstrates a fivefold expansion in ARBW compared to the single pair.
{"title":"Design of a Circularly-Polarized Microstrip Antenna by Utilizing Mutually-Coupled Resonators","authors":"Jia-Xiang Hao;Hui-Dong Li;Lei Zhu","doi":"10.1109/OJAP.2024.3454330","DOIUrl":"10.1109/OJAP.2024.3454330","url":null,"abstract":"This article proposes a design method for a circularly-polarized (CP) antenna, which is realized by using coupling effects. Initially, the desired electric(magnetic) coupling between two identical \u0000<inline-formula> <tex-math>$lambda$ </tex-math></inline-formula>\u0000/4 short-circuited microstrip line (MS-L) resonators can be generated when the short-circuited (opencircuited) ends of the resonators are in close proximity to each other. Besides, an orthogonal arrangement in space for these two resonators has been adopted to yield two orthogonal linearly-polarized (LP) waves. Therefore, a desired CP rotation can be achieved by choosing corresponding coupling types. Meanwhile, two equivalent circuit models are established and analyzed to deduce the formulas of the mutual inductance and mutual capacitance for the desired CP radiation. Afterwards, a binary array consisting of a magnetically coupled (MC) pair of resonators and an electrically coupled (EC) pair of resonators is proposed for expanding the axial ratio bandwidth (ARBW) and enhancing peak gain. Finally, a right-handed circularlypolarized (RHCP) antenna with magnetic coupling, a left-handed circularly-polarized (LHCP) antenna with electric coupling and a binary array are fabricated and tested. And an excellent agreement is validated between the experiment and simulation results. The measured results show that the binary array achieves a maximum gain of 5 dBic within its measured ARBW range of 3.535 – 3.615 GHz. In contrast, the single pairs (EC or MC pair) exhibit a gain of 3 dBic. Additionally, the array demonstrates a fivefold expansion in ARBW compared to the single pair.","PeriodicalId":34267,"journal":{"name":"IEEE Open Journal of Antennas and Propagation","volume":"5 6","pages":"1747-1757"},"PeriodicalIF":3.5,"publicationDate":"2024-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10664594","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142176044","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-03DOI: 10.1109/OJAP.2024.3454120
Xi Liao;Ping Zhou;Yang Wang;Jie Zhang
Sub-Terahertz communication has broad application prospects for realizing ultra-broadband sixth generation (6G) system. One fundamental challenge when moving to new spectrum is to understand the science of radio propagation and propose an accurate and effective channel prediction method. In this paper, we first conduct extensive vector network analyzer-based radio propagation measurements at 140 GHz and 220 GHz in indoor hallway and lobby environments and at 280 GHz in an indoor laboratory environment. Omnidirectional and best directional path loss are modeled by empirical single-band and multi-band path loss models. Numerical results demonstrate that large-scale close-in model in this paper is simpler and more physically-based compared to floating-intercept model. In particular, a path loss prediction method based on environment features is proposed, which can predict path loss directly by utilizing random forest method, and the propagation environment are defined and extracted by scatterer features and related features of the transmitter and receiver. The performance of the proposed method is better than that of empirical path loss models. The measured results not only enrich the datasets of indoor sub-THz channel propagation, also can guide communication systems, network planning and deployment for 6G and beyond.
{"title":"Path Loss Modeling and Environment Features Powered Prediction for Sub-THz Communication","authors":"Xi Liao;Ping Zhou;Yang Wang;Jie Zhang","doi":"10.1109/OJAP.2024.3454120","DOIUrl":"10.1109/OJAP.2024.3454120","url":null,"abstract":"Sub-Terahertz communication has broad application prospects for realizing ultra-broadband sixth generation (6G) system. One fundamental challenge when moving to new spectrum is to understand the science of radio propagation and propose an accurate and effective channel prediction method. In this paper, we first conduct extensive vector network analyzer-based radio propagation measurements at 140 GHz and 220 GHz in indoor hallway and lobby environments and at 280 GHz in an indoor laboratory environment. Omnidirectional and best directional path loss are modeled by empirical single-band and multi-band path loss models. Numerical results demonstrate that large-scale close-in model in this paper is simpler and more physically-based compared to floating-intercept model. In particular, a path loss prediction method based on environment features is proposed, which can predict path loss directly by utilizing random forest method, and the propagation environment are defined and extracted by scatterer features and related features of the transmitter and receiver. The performance of the proposed method is better than that of empirical path loss models. The measured results not only enrich the datasets of indoor sub-THz channel propagation, also can guide communication systems, network planning and deployment for 6G and beyond.","PeriodicalId":34267,"journal":{"name":"IEEE Open Journal of Antennas and Propagation","volume":"5 6","pages":"1734-1746"},"PeriodicalIF":3.5,"publicationDate":"2024-09-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10663670","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142223267","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-26DOI: 10.1109/OJAP.2024.3449752
Mahrukh Khan;Talha Murad;Nicholas Lusdyk
This paper presents a novel and insightful approach to beamforming a $2times 2$ antenna array using the theory of characteristic modes. The array comprises four rectangular patch antenna elements designed on an FR-4 substrate resonating at 2.4 GHz. The characteristic mode analysis (CMA) presented a fascinating physical insight into the surface current directions and the radiation characteristics of the array structure. The excitation of a specific characteristic mode led to the design of a dual-beam antenna array. After feed excitation, characteristic mode analysis (CMA) was employed to understand multi-beam pattern reconfigurability in the multi-port structure. The information of distinct and orthogonal modal characteristic fields guides the beamforming of multibeam arrays. Modal characteristic fields of specific modes were identified using a modal weighting coefficient that may combine upon port phase change for beamforming at a certain scan angle. The potential of multi-dimensional coverage of a multibeam array is presented by selecting the different phase combinations of feeding ports. The paper discusses the strengths and limitations of beam scanning due to the combination of modes. This physical insight is beneficial for future pattern reconfigurable antenna array design procedures. Measurements on a realized prototype are in a good agreement with simulations, proving the proposed concept.
{"title":"Beamforming Analysis of Dual Beam Antenna Array Using Theory of Characteristic Modes","authors":"Mahrukh Khan;Talha Murad;Nicholas Lusdyk","doi":"10.1109/OJAP.2024.3449752","DOIUrl":"10.1109/OJAP.2024.3449752","url":null,"abstract":"This paper presents a novel and insightful approach to beamforming a \u0000<inline-formula> <tex-math>$2times 2$ </tex-math></inline-formula>\u0000 antenna array using the theory of characteristic modes. The array comprises four rectangular patch antenna elements designed on an FR-4 substrate resonating at 2.4 GHz. The characteristic mode analysis (CMA) presented a fascinating physical insight into the surface current directions and the radiation characteristics of the array structure. The excitation of a specific characteristic mode led to the design of a dual-beam antenna array. After feed excitation, characteristic mode analysis (CMA) was employed to understand multi-beam pattern reconfigurability in the multi-port structure. The information of distinct and orthogonal modal characteristic fields guides the beamforming of multibeam arrays. Modal characteristic fields of specific modes were identified using a modal weighting coefficient that may combine upon port phase change for beamforming at a certain scan angle. The potential of multi-dimensional coverage of a multibeam array is presented by selecting the different phase combinations of feeding ports. The paper discusses the strengths and limitations of beam scanning due to the combination of modes. This physical insight is beneficial for future pattern reconfigurable antenna array design procedures. Measurements on a realized prototype are in a good agreement with simulations, proving the proposed concept.","PeriodicalId":34267,"journal":{"name":"IEEE Open Journal of Antennas and Propagation","volume":"5 6","pages":"1465-1475"},"PeriodicalIF":3.5,"publicationDate":"2024-08-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10646390","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142223268","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-22DOI: 10.1109/OJAP.2024.3448245
Elizvan Juarez;Marco A. Panduro;David H. Covarrubias;Alberto Reyna
This paper presents a new design proposal for the simplification of linear beam-forming networks by applying a novel phase interpolation technique. This paper proposes the strategic utilization of 1-to-3 division nodes and 2-to-1 recombination nodes to reconstructing the cophasal values necessary for radiation beam scanning in linear phased array systems. This novel technique simplifies the beam-forming network, achieving a reduction of phase shifters by up to 60% and ±18° of scan angle. These benefits are obtained using uniform amplitude excitation and without additional amplitude controls. The complete antenna system considers a broadband V-slot as antenna element for obtaining a bandwidth performance of approximately 1.2 GHz. This results in a 22% of bandwidth. This is illustrated by using a prototype with experimental measurement results and simulations based on electromagnetic solver (CST Microwave Studio). These results reveal an interesting reduction of phase shifters for a good trade-off of beam-steering range and bandwidth behavior. The experimental results are analyzed and compared with other techniques and previous works cited in the literature. This novel methodology provides interesting results of a high benefit for wireless applications of phased antenna systems.
{"title":"Simplification of Linear Beam-Forming Networks by Applying a Novel Phase Interpolation Technique","authors":"Elizvan Juarez;Marco A. Panduro;David H. Covarrubias;Alberto Reyna","doi":"10.1109/OJAP.2024.3448245","DOIUrl":"10.1109/OJAP.2024.3448245","url":null,"abstract":"This paper presents a new design proposal for the simplification of linear beam-forming networks by applying a novel phase interpolation technique. This paper proposes the strategic utilization of 1-to-3 division nodes and 2-to-1 recombination nodes to reconstructing the cophasal values necessary for radiation beam scanning in linear phased array systems. This novel technique simplifies the beam-forming network, achieving a reduction of phase shifters by up to 60% and ±18° of scan angle. These benefits are obtained using uniform amplitude excitation and without additional amplitude controls. The complete antenna system considers a broadband V-slot as antenna element for obtaining a bandwidth performance of approximately 1.2 GHz. This results in a 22% of bandwidth. This is illustrated by using a prototype with experimental measurement results and simulations based on electromagnetic solver (CST Microwave Studio). These results reveal an interesting reduction of phase shifters for a good trade-off of beam-steering range and bandwidth behavior. The experimental results are analyzed and compared with other techniques and previous works cited in the literature. This novel methodology provides interesting results of a high benefit for wireless applications of phased antenna systems.","PeriodicalId":34267,"journal":{"name":"IEEE Open Journal of Antennas and Propagation","volume":"5 6","pages":"1714-1723"},"PeriodicalIF":3.5,"publicationDate":"2024-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10643585","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142176045","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-08-22DOI: 10.1109/OJAP.2024.3448253
Demos Serghiou;Mohsen Khalily;Tim W. C. Brown;Rahim Tafazolli
This paper presents wideband channel measurements for indoor Non-Line-of-Sight (NLoS) fixed links operating at sub-Terahertz (sub-THz) frequencies (92.110 GHz) with single scattered reflections. Seemingly “smooth” surfaces generate substantial internal multipath causing frequency selective scattered reflections owing to the short wavelength. Unlike specular reflections, no single well-defined reflection point aligns the incidence angle ( $theta_{{mathrm {i}}}$ ) and reflection angle ( $theta_{{mathrm {r}}}$ ) to form the lowest path loss. This means that the scattering effect of the reflective surface gives reason to search for the best angular alignment of the Receiver (Rx) antenna given a specific angle from the Transmitter (Tx) antenna. The wideband effective Radar Cross Section (RCS) is derived and computed based on the bi-static radar equation, which specifically accounts for the effect of alignment angle on the defined frequency selective RCS. The measurements reveal alignment-variant angular scattering from large-scale discontinuities such as wall partitions, television screens and metallic reinforcement studs, offering valuable insights for the design and deployment of future wireless communications systems operating in the sub-THz band.
{"title":"Characterization of Effective RCS for Fixed NLoS Sub-THz Links With Single Scattered Reflections","authors":"Demos Serghiou;Mohsen Khalily;Tim W. C. Brown;Rahim Tafazolli","doi":"10.1109/OJAP.2024.3448253","DOIUrl":"10.1109/OJAP.2024.3448253","url":null,"abstract":"This paper presents wideband channel measurements for indoor Non-Line-of-Sight (NLoS) fixed links operating at sub-Terahertz (sub-THz) frequencies (92.110 GHz) with single scattered reflections. Seemingly “smooth” surfaces generate substantial internal multipath causing frequency selective scattered reflections owing to the short wavelength. Unlike specular reflections, no single well-defined reflection point aligns the incidence angle (\u0000<inline-formula> <tex-math>$theta_{{mathrm {i}}}$ </tex-math></inline-formula>\u0000) and reflection angle (\u0000<inline-formula> <tex-math>$theta_{{mathrm {r}}}$ </tex-math></inline-formula>\u0000) to form the lowest path loss. This means that the scattering effect of the reflective surface gives reason to search for the best angular alignment of the Receiver (Rx) antenna given a specific angle from the Transmitter (Tx) antenna. The wideband effective Radar Cross Section (RCS) is derived and computed based on the bi-static radar equation, which specifically accounts for the effect of alignment angle on the defined frequency selective RCS. The measurements reveal alignment-variant angular scattering from large-scale discontinuities such as wall partitions, television screens and metallic reinforcement studs, offering valuable insights for the design and deployment of future wireless communications systems operating in the sub-THz band.","PeriodicalId":34267,"journal":{"name":"IEEE Open Journal of Antennas and Propagation","volume":"5 6","pages":"1724-1733"},"PeriodicalIF":3.5,"publicationDate":"2024-08-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10643561","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142176047","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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