This paper introduces a low distortion radiation pattern ultra-wideband (UWB) transverse electromagnetic (TEM) horn antenna designed to operate in the 2 to 18 GHz frequency range. The modification is achieved using a non-uniform antenna feed without changing the antenna’s flare structure. The main-lobe radiation pattern of the antenna at higher frequencies eliminates ripples by using a non-uniform feeding technique compared to conventional TEM horn antennas, in which this issue exists. The measurement results pursue simulation results with a good agreement. The maximum measurement ga in of the antenna is 15 dBi for the operating range, and a voltage standing ratio (VSWR) of 1:2 has been obtained in the whole frequency band. The final dimensions of the fabricated antenna with the feed section are defined as $3.65, lambda _{0} times 2, lambda _{0} times 2, lambda _{0}$ compared to the previous studies, have smaller dimensions in terms of the free-space wavelength and low distortion, and no fluctuation in the main lobe in the H and E-plane of the radiation pattern between 2 to 18 GHz. The maximum measured ripple of the proposed TEM horn antenna at the main lobe is equal to 0.3 dB. These mentioned features of the proposed antenna are used as a part of ultra-wideband systems.
本文介绍了一种低失真辐射模式超宽带（UWB）横向电磁（TEM）喇叭天线，设计工作频率范围为 2 至 18 千兆赫。这种改进是在不改变天线扩口结构的情况下，利用非均匀天馈实现的。与存在波纹问题的传统 TEM 角天线相比，通过使用非均匀馈电技术，天线在较高频率下的主叶辐射模式消除了波纹。测量结果与仿真结果一致。天线在工作范围内的最大测量值为 15 dBi，整个频段的电压驻波比（VSWR）为 1:2。带馈电部分的制造天线的最终尺寸定义为 3.65 美元，lambda _{0} times 2, lambda _{0}, lambda _{0}, lambda _{0}.times 2, lambda _{0}与之前的研究相比，该天线的自由空间波长尺寸更小、失真度更低，并且在 2 到 18 GHz 之间的辐射模式中，H 平面和 E 平面的主叶没有波动。所提议的 TEM 号角天线在主波段的最大测量波纹等于 0.3 dB。所提天线的上述特点可用作超宽带系统的一部分。
{"title":"A Low Distortion Radiation Pattern Ultra-Wideband TEM Horn Antenna","authors":"Mahdi Zoghi;Farrokh Hodjatkashani;Mir Emad Lajevardi","doi":"10.1109/OJAP.2024.3437340","DOIUrl":"10.1109/OJAP.2024.3437340","url":null,"abstract":"This paper introduces a low distortion radiation pattern ultra-wideband (UWB) transverse electromagnetic (TEM) horn antenna designed to operate in the 2 to 18 GHz frequency range. The modification is achieved using a non-uniform antenna feed without changing the antenna’s flare structure. The main-lobe radiation pattern of the antenna at higher frequencies eliminates ripples by using a non-uniform feeding technique compared to conventional TEM horn antennas, in which this issue exists. The measurement results pursue simulation results with a good agreement. The maximum measurement ga in of the antenna is 15 dBi for the operating range, and a voltage standing ratio (VSWR) of 1:2 has been obtained in the whole frequency band. The final dimensions of the fabricated antenna with the feed section are defined as \u0000<inline-formula> <tex-math>$3.65, lambda _{0} times 2, lambda _{0} times 2, lambda _{0}$ </tex-math></inline-formula>\u0000 compared to the previous studies, have smaller dimensions in terms of the free-space wavelength and low distortion, and no fluctuation in the main lobe in the H and E-plane of the radiation pattern between 2 to 18 GHz. The maximum measured ripple of the proposed TEM horn antenna at the main lobe is equal to 0.3 dB. These mentioned features of the proposed antenna are used as a part of ultra-wideband systems.","PeriodicalId":34267,"journal":{"name":"IEEE Open Journal of Antennas and Propagation","volume":"5 6","pages":"1671-1680"},"PeriodicalIF":3.5,"publicationDate":"2024-08-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10621048","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141886515","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 : 2024-08-01DOI: 10.1109/OJAP.2024.3436557
Xiantao Yang;Elliot Leon Bennett;Ilkan Calisir;Qiang Hua;Jianliang Xiao;Yi Huang
In this paper, a comprehensive study of wideband dielectric resonator antennas (DRAs) loaded with special dispersive materials is given in detail. The concept and theory for a new class of wideband and compact DRAs are introduced for the first time using the new material whose relative permittivity is inversely proportional to the frequency power of n (i.e., $varepsilon _{r }$ (f) ${=} {k}$ / $f^{n}$ , k is a constant). Traditional DRAs are normally of limited bandwidth and unstable radiation patterns. The proposed new DRAs exhibit excellent advantages in bandwidth enhancement, size reduction, single-mode purity (predominantly supporting a single mode with minimal interference from other unwanted modes), and stable radiation patterns. The new dielectric resonator theory with wideband resonance characteristics is developed. Based on this, wideband and compact cylindrical and rectangular DRAs are designed and studied. The simulated and measured results demonstrate the merits of the proposed antennas. It is shown that without changing the structures, the percentage bandwidth of the proposed cylindrical DRA made of a dispersive material can be significantly increased to 120%, compared to the DRA using the traditional material with a constant permittivity (4%). The paper provides a new approach for making wideband and compact DRAs with stable radiation patterns for future wideband wireless communications and radar applications.
{"title":"A Study of Wideband Dielectric Resonator Antennas Loaded With Special Dispersive Materials","authors":"Xiantao Yang;Elliot Leon Bennett;Ilkan Calisir;Qiang Hua;Jianliang Xiao;Yi Huang","doi":"10.1109/OJAP.2024.3436557","DOIUrl":"10.1109/OJAP.2024.3436557","url":null,"abstract":"In this paper, a comprehensive study of wideband dielectric resonator antennas (DRAs) loaded with special dispersive materials is given in detail. The concept and theory for a new class of wideband and compact DRAs are introduced for the first time using the new material whose relative permittivity is inversely proportional to the frequency power of n (i.e., \u0000<inline-formula> <tex-math>$varepsilon _{r }$ </tex-math></inline-formula>\u0000(f) \u0000<inline-formula> <tex-math>${=} {k}$ </tex-math></inline-formula>\u0000 / \u0000<inline-formula> <tex-math>$f^{n}$ </tex-math></inline-formula>\u0000, k is a constant). Traditional DRAs are normally of limited bandwidth and unstable radiation patterns. The proposed new DRAs exhibit excellent advantages in bandwidth enhancement, size reduction, single-mode purity (predominantly supporting a single mode with minimal interference from other unwanted modes), and stable radiation patterns. The new dielectric resonator theory with wideband resonance characteristics is developed. Based on this, wideband and compact cylindrical and rectangular DRAs are designed and studied. The simulated and measured results demonstrate the merits of the proposed antennas. It is shown that without changing the structures, the percentage bandwidth of the proposed cylindrical DRA made of a dispersive material can be significantly increased to 120%, compared to the DRA using the traditional material with a constant permittivity (4%). The paper provides a new approach for making wideband and compact DRAs with stable radiation patterns for future wideband wireless communications and radar applications.","PeriodicalId":34267,"journal":{"name":"IEEE Open Journal of Antennas and Propagation","volume":"5 6","pages":"1658-1670"},"PeriodicalIF":3.5,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10620297","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141886512","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}
This paper presents a novel nondestructive, contactless moisture content sensor based on the Wheeler Cap measurement technique. The sensor comprises an electrically small antenna enclosed within a compact metallic cap, along with the material under test. The operating frequency of the sensor without material under test is 268.25 megahertz. By measuring the reflection coefficient at the input port of the antenna enclosed in the metallic cap, the moisture content of the material under test can be determined. The proposed sensor is aimed for moisture content measurement of the municipal solid waste, the primary feedstock for refuse-derived fuel utilized in waste-to-energy power plants. The moisture content of material under test can be determined using magnitude or frequency of the minimum reflection coefficient from the measured frequency response. Linear regression models are developed to establish the relationship between moisture content and the measured magnitude or frequency yielding coefficient of determination $R^{2}$ of 0.934 and 0.936, respectively. The sensor exhibits a sensitivity of 0.034 dBm decrease in magnitude and 0.097 MHz decrease in frequency per 1% increase in moisture content. This performance demonstrates the sensor’s potential as a reliable and accurate tool for moisture content measurement in WtE applications.
{"title":"Contactless Moisture Content Sensor Based on Wheeler Cap for Waste-to-Energy Plants","authors":"Prakorn Pratoomma;Adam Narbudowicz;Suramate Chalermwisutkul","doi":"10.1109/OJAP.2024.3437209","DOIUrl":"10.1109/OJAP.2024.3437209","url":null,"abstract":"This paper presents a novel nondestructive, contactless moisture content sensor based on the Wheeler Cap measurement technique. The sensor comprises an electrically small antenna enclosed within a compact metallic cap, along with the material under test. The operating frequency of the sensor without material under test is 268.25 megahertz. By measuring the reflection coefficient at the input port of the antenna enclosed in the metallic cap, the moisture content of the material under test can be determined. The proposed sensor is aimed for moisture content measurement of the municipal solid waste, the primary feedstock for refuse-derived fuel utilized in waste-to-energy power plants. The moisture content of material under test can be determined using magnitude or frequency of the minimum reflection coefficient from the measured frequency response. Linear regression models are developed to establish the relationship between moisture content and the measured magnitude or frequency yielding coefficient of determination \u0000<inline-formula> <tex-math>$R^{2}$ </tex-math></inline-formula>\u0000 of 0.934 and 0.936, respectively. The sensor exhibits a sensitivity of 0.034 dBm decrease in magnitude and 0.097 MHz decrease in frequency per 1% increase in moisture content. This performance demonstrates the sensor’s potential as a reliable and accurate tool for moisture content measurement in WtE applications.","PeriodicalId":34267,"journal":{"name":"IEEE Open Journal of Antennas and Propagation","volume":"5 5","pages":"1152-1165"},"PeriodicalIF":3.5,"publicationDate":"2024-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10620316","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141886516","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 : 2024-07-23DOI: 10.1109/OJAP.2024.3432592
Gonzalo Maldonado;Alberto Reyna;Luz. I. Balderas;Marco A. Panduro;Jesús Cruz Garza
This paper proposes an analytical method to calculate the switch-on sequences that provides Time Modulated Antenna Arrays (TMAA) with beam scanning in the sideband region. Such time sequences can be calculated to locate the main beam both in the azimuth and elevation planes. A comparison between H. Shanks’ method and the method proposed in this paper is presented. The radiation patterns of uniform linear, square and circular arrays are presented to demonstrate the efficacy of the proposed method. Additionally, a 6-element circular antenna array prototype for 5G applications was constructed. Such array resonates at the frequency of 3.612 GHz. The radiation patterns were measured in the anechoic chamber, demonstrating the effectiveness of the proposed method.
本文提出了一种分析方法，用于计算在边带区域进行波束扫描的时间调制天线阵列（TMAA）的接通时序。通过计算这种时序，可以在方位角和仰角平面上确定主波束的位置。本文对 H. Shanks 方法和本文提出的方法进行了比较。本文展示了均匀线性、方形和圆形阵列的辐射模式，以证明所提方法的有效性。此外，还构建了一个用于 5G 应用的 6 元圆形天线阵列原型。该阵列的谐振频率为 3.612 GHz。在电波暗室中测量了辐射模式，证明了所提方法的有效性。
{"title":"Beam Steering for Time Modulated Arrays","authors":"Gonzalo Maldonado;Alberto Reyna;Luz. I. Balderas;Marco A. Panduro;Jesús Cruz Garza","doi":"10.1109/OJAP.2024.3432592","DOIUrl":"10.1109/OJAP.2024.3432592","url":null,"abstract":"This paper proposes an analytical method to calculate the switch-on sequences that provides Time Modulated Antenna Arrays (TMAA) with beam scanning in the sideband region. Such time sequences can be calculated to locate the main beam both in the azimuth and elevation planes. A comparison between H. Shanks’ method and the method proposed in this paper is presented. The radiation patterns of uniform linear, square and circular arrays are presented to demonstrate the efficacy of the proposed method. Additionally, a 6-element circular antenna array prototype for 5G applications was constructed. Such array resonates at the frequency of 3.612 GHz. The radiation patterns were measured in the anechoic chamber, demonstrating the effectiveness of the proposed method.","PeriodicalId":34267,"journal":{"name":"IEEE Open Journal of Antennas and Propagation","volume":"5 6","pages":"1649-1657"},"PeriodicalIF":3.5,"publicationDate":"2024-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10606437","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141774384","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 : 2024-07-22DOI: 10.1109/OJAP.2024.3431536
Farzaneh Ahmadi;Jiming Song;Reza Zoughi
Laser powder bed fusion (LPBF) is a cost-effective and relatively fast additive manufacturing (AM) technique, utilizing a laser source to selectively melt metallic powder and produce objects with intricate geometries. Nevertheless, establishing effective real-time monitoring methods for this process remains a notable challenge. The interaction between the laser and metallic powder leads to the ejection of particles, referred to as spatter, with varying sizes, velocities, trajectories, and spatial distributions. Literature indicates that the behavior of these spatters can serve as a potential indicator of defect generation during the AM process. This study investigates the potential for employing a well-established electromagnetic (EM) model to monitor the scattering properties of spatters. This approach serves as a potential tool to identify variations in spattering behavior that might be associated with defect generation during the process. The study explores how parameters, such as spatial distribution and the number of particles (in a given volume), impact the scattering properties, accuracy, and efficiency of the method. Changes in spattering spatial distribution resulting from variations in processing parameters, including laser power, scan speed, and chamber pressure, were investigated. Some of these conditions resulted in the formation of a deep keyhole zone. The results demonstrated that monitoring radar cross-section (RCS) of the spatters could serve as a metric to distinguish between conditions that lead to a deeper keyhole and those that either do not create a keyhole zone or result in a shallower keyhole. Additionally, the concept of the “sphere-of-influence (SoI)” is used as a tool for improving computational efficiency and potential use in method validation. The insights from this study have the potential to contribute to the advancement of real-time LPBF monitoring, presenting possibilities for improved quality control and defect detection in AM processes.
激光粉末床熔融（LPBF）是一种具有成本效益且相对快速的增材制造（AM）技术，它利用激光源选择性地熔化金属粉末，生产出具有复杂几何形状的物体。然而，为这一过程建立有效的实时监控方法仍然是一个显著的挑战。激光与金属粉末之间的相互作用会导致不同大小、速度、轨迹和空间分布的颗粒喷射出来，这些颗粒被称为溅射物。文献表明，这些飞溅物的行为可作为 AM 过程中产生缺陷的潜在指标。本研究探讨了采用成熟的电磁（EM）模型来监测溅射物散射特性的可能性。这种方法是一种潜在的工具，可用于识别可能与工艺过程中缺陷产生有关的散射行为变化。该研究探讨了空间分布和粒子数量（在给定体积内）等参数如何影响该方法的散射特性、准确性和效率。研究调查了激光功率、扫描速度和腔体压力等加工参数变化导致的散射空间分布变化。其中一些条件导致了深锁孔区的形成。结果表明，监测溅射物的雷达横截面 (RCS) 可以作为区分导致较深锁孔的条件和不形成锁孔区或导致较浅锁孔的条件的指标。此外，"影响范围（SoI）"的概念被用作提高计算效率和方法验证的潜在工具。本研究的见解有可能促进实时 LPBF 监测的发展，为改进 AM 工艺的质量控制和缺陷检测提供可能性。
{"title":"Electromagnetic Scattering Properties of Metal Powder Cloud for Laser Powder Bed Fusion (LPBF) Additive Manufacturing (AM)","authors":"Farzaneh Ahmadi;Jiming Song;Reza Zoughi","doi":"10.1109/OJAP.2024.3431536","DOIUrl":"10.1109/OJAP.2024.3431536","url":null,"abstract":"Laser powder bed fusion (LPBF) is a cost-effective and relatively fast additive manufacturing (AM) technique, utilizing a laser source to selectively melt metallic powder and produce objects with intricate geometries. Nevertheless, establishing effective real-time monitoring methods for this process remains a notable challenge. The interaction between the laser and metallic powder leads to the ejection of particles, referred to as spatter, with varying sizes, velocities, trajectories, and spatial distributions. Literature indicates that the behavior of these spatters can serve as a potential indicator of defect generation during the AM process. This study investigates the potential for employing a well-established electromagnetic (EM) model to monitor the scattering properties of spatters. This approach serves as a potential tool to identify variations in spattering behavior that might be associated with defect generation during the process. The study explores how parameters, such as spatial distribution and the number of particles (in a given volume), impact the scattering properties, accuracy, and efficiency of the method. Changes in spattering spatial distribution resulting from variations in processing parameters, including laser power, scan speed, and chamber pressure, were investigated. Some of these conditions resulted in the formation of a deep keyhole zone. The results demonstrated that monitoring radar cross-section (RCS) of the spatters could serve as a metric to distinguish between conditions that lead to a deeper keyhole and those that either do not create a keyhole zone or result in a shallower keyhole. Additionally, the concept of the “sphere-of-influence (SoI)” is used as a tool for improving computational efficiency and potential use in method validation. The insights from this study have the potential to contribute to the advancement of real-time LPBF monitoring, presenting possibilities for improved quality control and defect detection in AM processes.","PeriodicalId":34267,"journal":{"name":"IEEE Open Journal of Antennas and Propagation","volume":"5 6","pages":"1639-1648"},"PeriodicalIF":3.5,"publicationDate":"2024-07-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10605898","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141774385","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}
Within the framework of the recent agri-food technological advancement, the design and validation of a methodology for the water content estimation in the Carasau bread manufacturing process is herein presented. Following a thorough evaluation of the dough dielectric properties, a suitable antenna layout has been selected, pointing out the advantages in the choice of a contactless narrow-band antenna in comparison to wide-band and dual-band ones. The presented simulated results are then validated using a prototype sensor and an ad hoc measurement system to confirm the antenna ability to discriminate among doughs with different water content. In addition, an accurate analysis of possible sources of misinterpretation of the results is presented.
{"title":"Preliminary Design and Test of a Microwave Inline Moisture Sensor for the Carasau Bread Industry","authors":"Giacomo Muntoni;Matteo B. Lodi;Alessandro Fedeli;Andrea Melis;Claudia Macciò;Matteo Pastorino;Andrea Randazzo;Giuseppe Mazzarella;Alessandro Fanti","doi":"10.1109/OJAP.2024.3431092","DOIUrl":"10.1109/OJAP.2024.3431092","url":null,"abstract":"Within the framework of the recent agri-food technological advancement, the design and validation of a methodology for the water content estimation in the Carasau bread manufacturing process is herein presented. Following a thorough evaluation of the dough dielectric properties, a suitable antenna layout has been selected, pointing out the advantages in the choice of a contactless narrow-band antenna in comparison to wide-band and dual-band ones. The presented simulated results are then validated using a prototype sensor and an ad hoc measurement system to confirm the antenna ability to discriminate among doughs with different water content. In addition, an accurate analysis of possible sources of misinterpretation of the results is presented.","PeriodicalId":34267,"journal":{"name":"IEEE Open Journal of Antennas and Propagation","volume":"5 5","pages":"1166-1180"},"PeriodicalIF":3.5,"publicationDate":"2024-07-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10604824","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141737210","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 : 2024-07-11DOI: 10.1109/OJAP.2024.3426651
Xin Guan;Yijing He;Zhenghui Xue;Wu Ren;Weiming Li
To achieve an omnidirectional circularly-polarized antenna mountable on metal platforms such as vehicle and aircraft is challenging work. In this paper, an omnidirectional circularly-polarized antenna is proposed. Specifically, a thin and compact open cavity loaded with a capacitive impedance surface is used to provide the horizontally-polarized electrical-field component. While the verticallypolarized electrical-field component is achieved by a thin open cavity placed above the metal ground with a small gap. Connecting the two radiating cavities with a metal plate, the omnidirectional circularlypolarized antenna can be constructed using one simple feed. Outstanding azimuth gain variation of less than 1 dB and axial ratio less than 3 dB are obtained for the proposed antenna. Owing to the proposed antenna has omnidirectional characteristics, it can be applied to a wide-angle scanning array. The proposed array consists of 1 × 16 omnidirectional circularly-polarized antennas mounted on a metal planform with half-wavelength spacing. The antenna array beam scanning is divided into broadside and endfire modes, achieving wide-angle scanning in the azimuth plane. For validation, a 1 × 16 array prototype is fabricated and experimentally tested. The measured results are consistent with the simulated results. The measured results show that the antenna can achieve good circularly-polarized radiation, with most of the axial ratio less than 3 dB at the main beam direction of the array. With the advantages of omnidirectional circularlypolarized and wide-angle scanning, the proposed antenna can be used in communications between high altitude and ground.
{"title":"Design an Omnidirectional Circularly-Polarized Antenna for Azimuth Wide-Angle Scanning Array","authors":"Xin Guan;Yijing He;Zhenghui Xue;Wu Ren;Weiming Li","doi":"10.1109/OJAP.2024.3426651","DOIUrl":"10.1109/OJAP.2024.3426651","url":null,"abstract":"To achieve an omnidirectional circularly-polarized antenna mountable on metal platforms such as vehicle and aircraft is challenging work. In this paper, an omnidirectional circularly-polarized antenna is proposed. Specifically, a thin and compact open cavity loaded with a capacitive impedance surface is used to provide the horizontally-polarized electrical-field component. While the verticallypolarized electrical-field component is achieved by a thin open cavity placed above the metal ground with a small gap. Connecting the two radiating cavities with a metal plate, the omnidirectional circularlypolarized antenna can be constructed using one simple feed. Outstanding azimuth gain variation of less than 1 dB and axial ratio less than 3 dB are obtained for the proposed antenna. Owing to the proposed antenna has omnidirectional characteristics, it can be applied to a wide-angle scanning array. The proposed array consists of 1 × 16 omnidirectional circularly-polarized antennas mounted on a metal planform with half-wavelength spacing. The antenna array beam scanning is divided into broadside and endfire modes, achieving wide-angle scanning in the azimuth plane. For validation, a 1 × 16 array prototype is fabricated and experimentally tested. The measured results are consistent with the simulated results. The measured results show that the antenna can achieve good circularly-polarized radiation, with most of the axial ratio less than 3 dB at the main beam direction of the array. With the advantages of omnidirectional circularlypolarized and wide-angle scanning, the proposed antenna can be used in communications between high altitude and ground.","PeriodicalId":34267,"journal":{"name":"IEEE Open Journal of Antennas and Propagation","volume":"5 6","pages":"1629-1638"},"PeriodicalIF":3.5,"publicationDate":"2024-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10596057","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141614608","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 : 2024-07-11DOI: 10.1109/OJAP.2024.3426624
Shaojie Wang;He-Xiu Xu;Mingzhao Wang;Shiwei Tang
A novel method to engineer high-gain and polarization-insensitive Fabry-Perot (FP) antenna with low scattering is presented by combining a polarization-insensitive broadband frequency selective rasorber with partially reflective surface (FSRP) and a reflective metasurface. The FSRP element consists of an upper indium tin oxide layer printed on polyethylene glycol terephthalate substrate, a metallic loop, and a metallic patch in the middle and bottom layer, respectively, which is designed to absorb most of out-of-band incidence while achieving in-band reflection. The bottom metallic patch is a partially reflected surface which is utilized to construct an FP resonant cavity with the reflective metasurface to ensure in-band radiation. The excellent performance of proposed FP antenna is demonstrated by simulations and measurements, revealing that the antenna exhibits an in-band peak measured gain of 21.8 dBiC at 12 GHz. Besides, a significant out-of-band scattering reduction is achieved within 9.9-11.3 GHz and 13.3-20 GHz under normal detection. Our paradigm setups a new avenue for low radar cross section of a high-gain antenna, promising great potential in practical applications.
{"title":"A Low-RCS, High-Gain and Polarization-Insensitive FP Antenna Combing Frequency Selective Rasorber and Metasurface","authors":"Shaojie Wang;He-Xiu Xu;Mingzhao Wang;Shiwei Tang","doi":"10.1109/OJAP.2024.3426624","DOIUrl":"10.1109/OJAP.2024.3426624","url":null,"abstract":"A novel method to engineer high-gain and polarization-insensitive Fabry-Perot (FP) antenna with low scattering is presented by combining a polarization-insensitive broadband frequency selective rasorber with partially reflective surface (FSRP) and a reflective metasurface. The FSRP element consists of an upper indium tin oxide layer printed on polyethylene glycol terephthalate substrate, a metallic loop, and a metallic patch in the middle and bottom layer, respectively, which is designed to absorb most of out-of-band incidence while achieving in-band reflection. The bottom metallic patch is a partially reflected surface which is utilized to construct an FP resonant cavity with the reflective metasurface to ensure in-band radiation. The excellent performance of proposed FP antenna is demonstrated by simulations and measurements, revealing that the antenna exhibits an in-band peak measured gain of 21.8 dBiC at 12 GHz. Besides, a significant out-of-band scattering reduction is achieved within 9.9-11.3 GHz and 13.3-20 GHz under normal detection. Our paradigm setups a new avenue for low radar cross section of a high-gain antenna, promising great potential in practical applications.","PeriodicalId":34267,"journal":{"name":"IEEE Open Journal of Antennas and Propagation","volume":"5 6","pages":"1623-1628"},"PeriodicalIF":3.5,"publicationDate":"2024-07-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10594771","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141609656","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 : 2024-07-10DOI: 10.1109/OJAP.2024.3425915
Tobias Doeker;Johannes M. Eckhardt;Carla E. Reinhardt;Thomas Kürner
This article provides a comprehensive overview of calibrating a correlation-based channel sounder designed for the low terahertz (THz) frequency range. The calibration process outlined herein encompasses fundamental aspects, including the calibration of the measured delay and amplitude of the channel impulse response (CIR). Specifically, it discusses the influence of the utilized waveguides during a back-to-back (B2B) calibration, as well as the effects of antennas, and noise floor estimation. Furthermore, the calibration procedure is enhanced through deconvolution to mitigate the impact of the measurement system itself. Specifically, the discussion addresses the windowing technique applied to the deconvolved signal. Lastly, additional considerations such as averaging, interpolation, MIMO configurations, and highresolution measurements are discussed.
{"title":"Time-Domain Channel Sounder Calibration at Low Terahertz Band","authors":"Tobias Doeker;Johannes M. Eckhardt;Carla E. Reinhardt;Thomas Kürner","doi":"10.1109/OJAP.2024.3425915","DOIUrl":"10.1109/OJAP.2024.3425915","url":null,"abstract":"This article provides a comprehensive overview of calibrating a correlation-based channel sounder designed for the low terahertz (THz) frequency range. The calibration process outlined herein encompasses fundamental aspects, including the calibration of the measured delay and amplitude of the channel impulse response (CIR). Specifically, it discusses the influence of the utilized waveguides during a back-to-back (B2B) calibration, as well as the effects of antennas, and noise floor estimation. Furthermore, the calibration procedure is enhanced through deconvolution to mitigate the impact of the measurement system itself. Specifically, the discussion addresses the windowing technique applied to the deconvolved signal. Lastly, additional considerations such as averaging, interpolation, MIMO configurations, and highresolution measurements are discussed.","PeriodicalId":34267,"journal":{"name":"IEEE Open Journal of Antennas and Propagation","volume":"5 6","pages":"1598-1611"},"PeriodicalIF":3.5,"publicationDate":"2024-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10592059","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141586067","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 : 2024-07-10DOI: 10.1109/OJAP.2024.3426608
Amir Jafargholi;Mahmood Safaei;Romain Fleury;Rahim Tafazolli
This paper addresses the 3D nature of traditional Electronically Steerable Parasitic Array Radiators (ESPARs). Additionally, the required distance between the main radiator and the parasitic elements usually affects the antenna’s electrical size and the frequency bandwidth. To overcome these issues, the cylindrical parasitic elements in conventional ESPARs are replaced with Metamaterial-inspired structures that mimic artificial magnetic conductors (AMC). The AMC is realized by a capacitively loaded loop (CLL). PIN diodes electrically control the CLL’s behavior while radially loading a printed loop antenna. Switching ON/OFF the diodes changes the direction of the main lobe, resulting in a compact, single-layer, low-profile, and cost-effective structure. By replacing the PIN diodes with varactors, a dual-band and frequency-reconfigurable ESPAR are designed and implemented, which is not possible in traditional ESPAR structures.
{"title":"Low-Profile ESPAR Using Metamaterial-Inspired Structure","authors":"Amir Jafargholi;Mahmood Safaei;Romain Fleury;Rahim Tafazolli","doi":"10.1109/OJAP.2024.3426608","DOIUrl":"10.1109/OJAP.2024.3426608","url":null,"abstract":"This paper addresses the 3D nature of traditional Electronically Steerable Parasitic Array Radiators (ESPARs). Additionally, the required distance between the main radiator and the parasitic elements usually affects the antenna’s electrical size and the frequency bandwidth. To overcome these issues, the cylindrical parasitic elements in conventional ESPARs are replaced with Metamaterial-inspired structures that mimic artificial magnetic conductors (AMC). The AMC is realized by a capacitively loaded loop (CLL). PIN diodes electrically control the CLL’s behavior while radially loading a printed loop antenna. Switching ON/OFF the diodes changes the direction of the main lobe, resulting in a compact, single-layer, low-profile, and cost-effective structure. By replacing the PIN diodes with varactors, a dual-band and frequency-reconfigurable ESPAR are designed and implemented, which is not possible in traditional ESPAR structures.","PeriodicalId":34267,"journal":{"name":"IEEE Open Journal of Antennas and Propagation","volume":"5 6","pages":"1612-1622"},"PeriodicalIF":3.5,"publicationDate":"2024-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10594769","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141586068","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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