Pub Date : 2025-02-19DOI: 10.1109/OJAP.2025.3543576
Ting Zang;Gaobiao Xiao
In this paper, the efficient optimization algorithm for synthesizing shaped beams is extended to the synthesis of radiation patterns of planar current sheets that have different beams and polarizations on the two sides of the source plane. The radiation pattern is described with a real-valued function, which is expressed with the superposition of entire functions and its extrema can be quickly located by searching on a fixed uniform grid in the k-space. By flexibly tuning the positions of the extrema, the ripples in the main beam and the levels of the sidelobes can be effectively controlled. As the number of the extrema in the radiation pattern is approximately equal to the effective number of degrees of freedom (NDF) of the far field, the optimization algorithm can converge fast. Numerical examples show that the optimization results can be improved by refining the uniform grids in the k-space.
{"title":"Synthesis of Shaped-Beam Radiation Patterns With Efficient Optimization Algorithm","authors":"Ting Zang;Gaobiao Xiao","doi":"10.1109/OJAP.2025.3543576","DOIUrl":"https://doi.org/10.1109/OJAP.2025.3543576","url":null,"abstract":"In this paper, the efficient optimization algorithm for synthesizing shaped beams is extended to the synthesis of radiation patterns of planar current sheets that have different beams and polarizations on the two sides of the source plane. The radiation pattern is described with a real-valued function, which is expressed with the superposition of entire functions and its extrema can be quickly located by searching on a fixed uniform grid in the k-space. By flexibly tuning the positions of the extrema, the ripples in the main beam and the levels of the sidelobes can be effectively controlled. As the number of the extrema in the radiation pattern is approximately equal to the effective number of degrees of freedom (NDF) of the far field, the optimization algorithm can converge fast. Numerical examples show that the optimization results can be improved by refining the uniform grids in the k-space.","PeriodicalId":34267,"journal":{"name":"IEEE Open Journal of Antennas and Propagation","volume":"6 3","pages":"694-704"},"PeriodicalIF":3.5,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10892263","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144170952","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 : 2025-02-19DOI: 10.1109/OJAP.2025.3543518
Keisuke Matsui;Hiroaki Nakabayashi;Akihiko Hirata
This study examines the seasonal variation in vegetation loss and the effects of moving foliage on signal propagation at the 300 GHz band. The variation in vegetation loss across seasons aligns well with the ITU-R model when parameters are adjusted for the month exhibiting maximum vegetation loss. During leafless seasons, slow fading is characterized by a frequency component below 0.2 Hz and occurs predominantly due to branch vibrations caused by wind. In environments where foliage consistently obstructs the line of sight between transmitter and receiver (quasi-line-of-sight, QLOS), rapid fading occurs due to foliage movement, with frequency components reaching up to 20 Hz. Both slow and rapid fading patterns in vegetation loss approximate the Nakagami distribution. Conversely, when foliage is sparse and wind causes intermittent shifts between line-of-sight and QLOS conditions, neither the Rician nor Nakagami models adequately represent the experimental data. This discrepancy is primarily due to significant variations in median vegetation loss values depending on whether the propagation path is obstructed by foliage. This study provides new insights into the dynamics of vegetation-induced signal fading at the 300 GHz band and demonstrates that seasonal variations significantly influence propagation characteristics.
{"title":"Evaluating Vegetation Attenuation Characteristics at the 300-GHz Band","authors":"Keisuke Matsui;Hiroaki Nakabayashi;Akihiko Hirata","doi":"10.1109/OJAP.2025.3543518","DOIUrl":"https://doi.org/10.1109/OJAP.2025.3543518","url":null,"abstract":"This study examines the seasonal variation in vegetation loss and the effects of moving foliage on signal propagation at the 300 GHz band. The variation in vegetation loss across seasons aligns well with the ITU-R model when parameters are adjusted for the month exhibiting maximum vegetation loss. During leafless seasons, slow fading is characterized by a frequency component below 0.2 Hz and occurs predominantly due to branch vibrations caused by wind. In environments where foliage consistently obstructs the line of sight between transmitter and receiver (quasi-line-of-sight, QLOS), rapid fading occurs due to foliage movement, with frequency components reaching up to 20 Hz. Both slow and rapid fading patterns in vegetation loss approximate the Nakagami distribution. Conversely, when foliage is sparse and wind causes intermittent shifts between line-of-sight and QLOS conditions, neither the Rician nor Nakagami models adequately represent the experimental data. This discrepancy is primarily due to significant variations in median vegetation loss values depending on whether the propagation path is obstructed by foliage. This study provides new insights into the dynamics of vegetation-induced signal fading at the 300 GHz band and demonstrates that seasonal variations significantly influence propagation characteristics.","PeriodicalId":34267,"journal":{"name":"IEEE Open Journal of Antennas and Propagation","volume":"6 2","pages":"621-629"},"PeriodicalIF":3.5,"publicationDate":"2025-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10892210","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143706810","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 : 2025-02-18DOI: 10.1109/OJAP.2025.3543251
Kai Qin;Bingjie Xiang;Kwai-Man Luk
A new 2-D scanning leaky-wave antenna (LWA) design is proposed, with a scanning range larger than competitors. It consists of a 1-bit reconfigurable magneto-electric (ME) dipole array and a pillbox beam-forming network (BFN). The probe-fed ME dipole is minimized to fit the holographic method and is introduced in LWA for the first time. A p-i-n diode is loaded in the L-shaped directly-fed probe to control whether it radiates. The dispersion characteristic of the linear LWA is examined to validate the effectiveness of the holographic method. A procedure is proposed to select the port and hologram for any-angle 2-D beam scanning. The prototype is fabricated and measured, and the results demonstrate the improved scanning range. The scanning range under the 3 dB gain decline condition covers ±54° across the broadside in the H-plane and ±37° in the E-plane in simulation. This design has the advantage of a wider scanning angle, 2-D scanning capability, and low cost. It may find applications in sensing, base stations, and vehicle communications.
{"title":"Fixed-Frequency 2-D Wide-Angle Scanning Leaky-Wave Array With Reconfigurable Probe-Fed Magneto-Electric Dipole","authors":"Kai Qin;Bingjie Xiang;Kwai-Man Luk","doi":"10.1109/OJAP.2025.3543251","DOIUrl":"https://doi.org/10.1109/OJAP.2025.3543251","url":null,"abstract":"A new 2-D scanning leaky-wave antenna (LWA) design is proposed, with a scanning range larger than competitors. It consists of a 1-bit reconfigurable magneto-electric (ME) dipole array and a pillbox beam-forming network (BFN). The probe-fed ME dipole is minimized to fit the holographic method and is introduced in LWA for the first time. A p-i-n diode is loaded in the L-shaped directly-fed probe to control whether it radiates. The dispersion characteristic of the linear LWA is examined to validate the effectiveness of the holographic method. A procedure is proposed to select the port and hologram for any-angle 2-D beam scanning. The prototype is fabricated and measured, and the results demonstrate the improved scanning range. The scanning range under the 3 dB gain decline condition covers ±54° across the broadside in the H-plane and ±37° in the E-plane in simulation. This design has the advantage of a wider scanning angle, 2-D scanning capability, and low cost. It may find applications in sensing, base stations, and vehicle communications.","PeriodicalId":34267,"journal":{"name":"IEEE Open Journal of Antennas and Propagation","volume":"6 2","pages":"613-620"},"PeriodicalIF":3.5,"publicationDate":"2025-02-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10891697","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143706811","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 : 2025-02-12DOI: 10.1109/OJAP.2025.3541235
Xiangyu Yin;Wu Ren;Zhenghui Xue;Weiming Li
In this paper, a wide-angle scanning circularly polarized phased array with stable gain is proposed. The proposed antenna array is composed of truncated microstrip antennas, four rows of mushroom metamaterials, and two tensor holographic metasurfaces. The mushroom metamaterials generate TM10 mode on the same plane as the antenna elements, compensating for the imbalance between horizontal and vertical polarization when the beam pattern of the phased array is steered to a wide-angle point. Meanwhile, the tensor holographic metasurfaces convert surface waves into circularly polarized leaky waves, which superimpose on the radiation of the antenna array, thereby improving the axis ratio and increasing the realized gain. Furthermore, an eight-element linear phased array with the circularly polarized and scanning gain enhanced metamaterials are fabricated. The measured results show that the axial ratio of the proposed wide-angle scanning antenna array remains below 3 dB, the scanning range is from −60° to 65°, and the gain fluctuation is less than 1.8 dB in the operating frequency range 10.1-10.7 GHz. In general, the proposed antenna array loaded metamaterials have the advantages of stable scanning gain, low profile and easy to fabricate, thus satisfying the requirements of satellite and radar applications.
{"title":"Metamaterial-Based Wide-Angle Scanning Circularly Polarized Phased Array With Stable Gain","authors":"Xiangyu Yin;Wu Ren;Zhenghui Xue;Weiming Li","doi":"10.1109/OJAP.2025.3541235","DOIUrl":"https://doi.org/10.1109/OJAP.2025.3541235","url":null,"abstract":"In this paper, a wide-angle scanning circularly polarized phased array with stable gain is proposed. The proposed antenna array is composed of truncated microstrip antennas, four rows of mushroom metamaterials, and two tensor holographic metasurfaces. The mushroom metamaterials generate TM10 mode on the same plane as the antenna elements, compensating for the imbalance between horizontal and vertical polarization when the beam pattern of the phased array is steered to a wide-angle point. Meanwhile, the tensor holographic metasurfaces convert surface waves into circularly polarized leaky waves, which superimpose on the radiation of the antenna array, thereby improving the axis ratio and increasing the realized gain. Furthermore, an eight-element linear phased array with the circularly polarized and scanning gain enhanced metamaterials are fabricated. The measured results show that the axial ratio of the proposed wide-angle scanning antenna array remains below 3 dB, the scanning range is from −60° to 65°, and the gain fluctuation is less than 1.8 dB in the operating frequency range 10.1-10.7 GHz. In general, the proposed antenna array loaded metamaterials have the advantages of stable scanning gain, low profile and easy to fabricate, thus satisfying the requirements of satellite and radar applications.","PeriodicalId":34267,"journal":{"name":"IEEE Open Journal of Antennas and Propagation","volume":"6 2","pages":"594-602"},"PeriodicalIF":3.5,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10883338","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143706697","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 : 2025-02-12DOI: 10.1109/OJAP.2025.3541420
Miguel Fernández;Carlos Vázquez;Samuel Ver Hoeye
In this work, a dual-mode, dual-polarization fully-woven textile antenna for simultaneous wireless information and power transfer in the 2.4 GHz band is presented. It is based on a square patch with two independent ports. The first port is implemented with an offset T-match structure, to which a singlediode rectifier is connected. The selected feeding technique allows to obtain complex-conjugate impedance matching with the rectifier and right-hand circular polarization for the wireless power transfer mode. On the other hand, for the information transfer mode, a coaxial probe is used to excite the antenna with left-hand circular polarization, in order to minimize the coupling between both modes. The combination of fully-woven technology with the implementation of the rectifier on a carrier thread provides a high degree of integration and robustness. A prototype was implemented and experimentally characterized, showing good agreement with simulation results. Furthermore, the measured RF-DC conversion efficiency in the wireless power transfer mode is about 50% when the available power at the rectifier input is -10 dBm, which is comparable with the state of the art for textile rectennas.
{"title":"Dual-Mode, Dual-Polarization Fully-Woven Textile Antenna for Simultaneous Wireless Information and Power Transfer Applications in the 2.4 GHz Band","authors":"Miguel Fernández;Carlos Vázquez;Samuel Ver Hoeye","doi":"10.1109/OJAP.2025.3541420","DOIUrl":"https://doi.org/10.1109/OJAP.2025.3541420","url":null,"abstract":"In this work, a dual-mode, dual-polarization fully-woven textile antenna for simultaneous wireless information and power transfer in the 2.4 GHz band is presented. It is based on a square patch with two independent ports. The first port is implemented with an offset T-match structure, to which a singlediode rectifier is connected. The selected feeding technique allows to obtain complex-conjugate impedance matching with the rectifier and right-hand circular polarization for the wireless power transfer mode. On the other hand, for the information transfer mode, a coaxial probe is used to excite the antenna with left-hand circular polarization, in order to minimize the coupling between both modes. The combination of fully-woven technology with the implementation of the rectifier on a carrier thread provides a high degree of integration and robustness. A prototype was implemented and experimentally characterized, showing good agreement with simulation results. Furthermore, the measured RF-DC conversion efficiency in the wireless power transfer mode is about 50% when the available power at the rectifier input is -10 dBm, which is comparable with the state of the art for textile rectennas.","PeriodicalId":34267,"journal":{"name":"IEEE Open Journal of Antennas and Propagation","volume":"6 2","pages":"603-612"},"PeriodicalIF":3.5,"publicationDate":"2025-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10883645","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143706696","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 : 2025-02-04DOI: 10.1109/OJAP.2025.3538686
Satyajit Chakrabarti;Debatosh Guha
near square Dielectric Resonator Antenna (DRA) geometry with dual-aperture feeding has been explored. This aims in achieving a number of attractive features from a standalone unit as well as a 4-element subarray. Unlike the earlier designs, it demonstrates four reconfigurable polarization states which are realized by conceiving a new near square shape of the DRA along with a novel feeding concept, proposed for the first time. They enable the subarray to significantly enhance the cross-polar discrimination (XPD). The design principles for dual-linear and dual-circular polarizations have been demonstrated and experimentally verified using a set of S-band prototypes. A dedicated digital phase network cum controller incorporating active switches has also been fabricated for practical examinations. A standalone prototype exhibits over 24.59% 10-dB return loss bandwidth at both ports with more than 40 dB inter-port isolation. It promises about 5.9 dBi/dBic consistent peak gain for all polarization states with more than 20 dB XPD. The subarray prototype reveals comparable 10-dB return loss bandwidths with more than 30 dB port-isolation and 25 dB XPD. The peak gain appears consistently around 11 dBi/dBic for all polarization states.
探讨了双孔径馈电的近方形介质谐振器天线几何结构。这样做的目的是从一个独立单元和一个4元素子阵列中获得许多有吸引力的特性。与早期的设计不同，它展示了四种可重构的极化状态，这是通过构想一个新的近方形DRA形状以及首次提出的新颖馈电概念来实现的。它们使子阵列显著增强了交叉极性辨别（XPD）。双线偏振和双圆偏振的设计原理已经被证明，并使用一组s波段原型实验验证。还制作了一个专用的数字相位网络和包含有源开关的控制器，用于实际测试。一个独立的原型在两个端口上显示超过24.59%的10 dB回波损耗带宽，端口间隔离超过40 dB。它承诺在超过20 dB XPD的所有极化状态下都有5.9 dBi/dBic一致的峰值增益。该子阵列原型具有10 dB的回波损耗带宽，具有超过30 dB的端口隔离和25 dB的XPD。在所有偏振态下，峰值增益始终在11 dBi/dBic左右出现。
{"title":"Dual-Fed DRA Subarrays Featuring Versatile Polarization Reconfigurability With High Port Isolation and Suppressed Cross-Polar Radiations","authors":"Satyajit Chakrabarti;Debatosh Guha","doi":"10.1109/OJAP.2025.3538686","DOIUrl":"https://doi.org/10.1109/OJAP.2025.3538686","url":null,"abstract":"near square Dielectric Resonator Antenna (DRA) geometry with dual-aperture feeding has been explored. This aims in achieving a number of attractive features from a standalone unit as well as a 4-element subarray. Unlike the earlier designs, it demonstrates four reconfigurable polarization states which are realized by conceiving a new near square shape of the DRA along with a novel feeding concept, proposed for the first time. They enable the subarray to significantly enhance the cross-polar discrimination (XPD). The design principles for dual-linear and dual-circular polarizations have been demonstrated and experimentally verified using a set of S-band prototypes. A dedicated digital phase network cum controller incorporating active switches has also been fabricated for practical examinations. A standalone prototype exhibits over 24.59% 10-dB return loss bandwidth at both ports with more than 40 dB inter-port isolation. It promises about 5.9 dBi/dBic consistent peak gain for all polarization states with more than 20 dB XPD. The subarray prototype reveals comparable 10-dB return loss bandwidths with more than 30 dB port-isolation and 25 dB XPD. The peak gain appears consistently around 11 dBi/dBic for all polarization states.","PeriodicalId":34267,"journal":{"name":"IEEE Open Journal of Antennas and Propagation","volume":"6 2","pages":"560-577"},"PeriodicalIF":3.5,"publicationDate":"2025-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10870296","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143698172","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 : 2025-02-04DOI: 10.1109/OJAP.2025.3538797
Margaux Bruliard;Marcello Zucchi;Giuseppe Vecchi
The Impedance Boundary Condition (IBC) is a homogenization approximation of great importance, especially in the design of metasurfaces. However, the standard Electric-Field Integral-Equation formulation of the IBC boundary-value problem (EFIE-IBC) has been shown to lead to numerical instabilities for some impedance ranges of practical interest, in particular inductive reactances. This contribution shows that the numerical instabilities are due to an intrinsic ill-conditioning of the EFIE-IBC operator for the concerned surface impedance values, that can degenerate into an ill-posedness that does not allow for definite solution. Hence, the stable discretization of the EFIE-IBC operator requires a regularization. The analysis leads to a proposed regularization by systematically limiting the wavenumber spectrum of the basis functions, which amounts to a spatial filtering. This is implemented using entire-domain basis functions. Given the possible ill-posedness, we devise two “ground truth” test examples starting from a physical metasurface, then approximated via IBC. Comparison to ground truth results shows that the standard EFIE-IBC may lead to significant errors, and that these may be challenging to detect. Conversely, the regularized system yields stable results that well match the ground truth of the physical structure of which the IBC is an approximation.
{"title":"Stability Analysis of the EFIE-IBC Formulation and Regularization via Spatial Filtering","authors":"Margaux Bruliard;Marcello Zucchi;Giuseppe Vecchi","doi":"10.1109/OJAP.2025.3538797","DOIUrl":"https://doi.org/10.1109/OJAP.2025.3538797","url":null,"abstract":"The Impedance Boundary Condition (IBC) is a homogenization approximation of great importance, especially in the design of metasurfaces. However, the standard Electric-Field Integral-Equation formulation of the IBC boundary-value problem (EFIE-IBC) has been shown to lead to numerical instabilities for some impedance ranges of practical interest, in particular inductive reactances. This contribution shows that the numerical instabilities are due to an intrinsic ill-conditioning of the EFIE-IBC operator for the concerned surface impedance values, that can degenerate into an ill-posedness that does not allow for definite solution. Hence, the stable discretization of the EFIE-IBC operator requires a regularization. The analysis leads to a proposed regularization by systematically limiting the wavenumber spectrum of the basis functions, which amounts to a spatial filtering. This is implemented using entire-domain basis functions. Given the possible ill-posedness, we devise two “ground truth” test examples starting from a physical metasurface, then approximated via IBC. Comparison to ground truth results shows that the standard EFIE-IBC may lead to significant errors, and that these may be challenging to detect. Conversely, the regularized system yields stable results that well match the ground truth of the physical structure of which the IBC is an approximation.","PeriodicalId":34267,"journal":{"name":"IEEE Open Journal of Antennas and Propagation","volume":"6 2","pages":"578-593"},"PeriodicalIF":3.5,"publicationDate":"2025-02-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10870329","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143698303","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}
In order to ensure high-resolution angle estimation results, antenna apertures of radar sensors become large relative to the wavelength. To prevent high sidelobe levels, the number of antennas is constantly increased, generally through the employment of multiple-input multiple-output operation. As systems become larger relative to the wavelength, influences of near-field effects in calibration measurements become more critical. To achieve precise calibrations despite near-field effects, calibration algorithms must be developed further. This paper proposes the deployment of sub-apertures to avoid near-field effects and to reduce the calibration effort, which is in this work related to the number of measuring points in the calibration measurement. An algorithm to create beneficial sub-apertures from a large array based on clustering is described. This allows the far-field distance to be reduced, as well as the effort required for state-of-the-art calibration methods, which depends on the aperture size. The trade-off between the benefits and error propagations as well as other limitations by the deployment of an increasing number of sub-apertures is demonstrated by simulations and measurements. Exemplary measurements show that even for large arrays in compact measuring chambers, far-field like conditions can be created. Finally, it is exemplarily demonstrated that the measurement effort is decreased by nearly 93 percent compared to a conventional calibration approach.
{"title":"A Sub-Aperture-Based Calibration Algorithm for MIMO Antenna Arrays","authors":"Matthias Linder;Daniel Schmidt;Dominik Schwarz;Nico Riese;Christian Waldschmidt","doi":"10.1109/OJAP.2025.3537681","DOIUrl":"https://doi.org/10.1109/OJAP.2025.3537681","url":null,"abstract":"In order to ensure high-resolution angle estimation results, antenna apertures of radar sensors become large relative to the wavelength. To prevent high sidelobe levels, the number of antennas is constantly increased, generally through the employment of multiple-input multiple-output operation. As systems become larger relative to the wavelength, influences of near-field effects in calibration measurements become more critical. To achieve precise calibrations despite near-field effects, calibration algorithms must be developed further. This paper proposes the deployment of sub-apertures to avoid near-field effects and to reduce the calibration effort, which is in this work related to the number of measuring points in the calibration measurement. An algorithm to create beneficial sub-apertures from a large array based on clustering is described. This allows the far-field distance to be reduced, as well as the effort required for state-of-the-art calibration methods, which depends on the aperture size. The trade-off between the benefits and error propagations as well as other limitations by the deployment of an increasing number of sub-apertures is demonstrated by simulations and measurements. Exemplary measurements show that even for large arrays in compact measuring chambers, far-field like conditions can be created. Finally, it is exemplarily demonstrated that the measurement effort is decreased by nearly 93 percent compared to a conventional calibration approach.","PeriodicalId":34267,"journal":{"name":"IEEE Open Journal of Antennas and Propagation","volume":"6 2","pages":"548-559"},"PeriodicalIF":3.5,"publicationDate":"2025-01-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10869335","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143698270","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 : 2025-01-29DOI: 10.1109/OJAP.2025.3526037
{"title":"IEEE ANTENNAS AND PROPAGATION SOCIETY","authors":"","doi":"10.1109/OJAP.2025.3526037","DOIUrl":"https://doi.org/10.1109/OJAP.2025.3526037","url":null,"abstract":"","PeriodicalId":34267,"journal":{"name":"IEEE Open Journal of Antennas and Propagation","volume":"6 1","pages":"C2-C2"},"PeriodicalIF":3.5,"publicationDate":"2025-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10857667","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143107005","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 : 2025-01-29DOI: 10.1109/OJAP.2025.3526041
{"title":"IEEE Open Journal of Antennas and Propagation Instructions for authors","authors":"","doi":"10.1109/OJAP.2025.3526041","DOIUrl":"https://doi.org/10.1109/OJAP.2025.3526041","url":null,"abstract":"","PeriodicalId":34267,"journal":{"name":"IEEE Open Journal of Antennas and Propagation","volume":"6 1","pages":"C3-C3"},"PeriodicalIF":3.5,"publicationDate":"2025-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10857666","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143106984","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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