Pub Date : 2025-03-12DOI: 10.1109/OJAP.2025.3568926
Haoqing Wen;Qi Wu
In integrated communications and navigation systems on hypersonic vehicles, circularly polarized (CP) antennas require wide axial-ratio (AR) beamwidths to ensure the reception of signals at low elevation angles, even when embedded in a thermal protection system (TPS). This paper analyzes electromagnetic interactions between CP antennas and TPS through the reciprocal and transmission line (TL) theories. A method is proposed to design an artificial reflecting surface (ARS) by calculating its optimal equivalent circuit. The designed ARS restores the CP properties of an embedded antenna by substituting its perfect electric conductor (PEC) ground. A dual-band 3/7 GHz CP antenna is designed and fabricated to verify the proposed theoretical method. By loading a double-layer ARS with serpentine loop and serpentine slot units, several negative effects of TPS are mitigated, resulting in resonance depth restoration and AR bandwidth widening. In particular, the 3 dB AR beamwidth of the proposed CP antenna covered by a double-layer TPS is significantly broadened, whose AR beams are widened to 110° on average in the frequency range of 2.91-3.16 GHz and to 65° on average in the frequency range of 6.69-7.22 GHz. The realized CP gains of the antenna are more than 5.0 dBc throughout the working bands.
{"title":"Dual-Band, Wide-AR Beamwidth, CP Antenna With Artificial Reflecting Surface for Hypersonic Vehicles","authors":"Haoqing Wen;Qi Wu","doi":"10.1109/OJAP.2025.3568926","DOIUrl":"https://doi.org/10.1109/OJAP.2025.3568926","url":null,"abstract":"In integrated communications and navigation systems on hypersonic vehicles, circularly polarized (CP) antennas require wide axial-ratio (AR) beamwidths to ensure the reception of signals at low elevation angles, even when embedded in a thermal protection system (TPS). This paper analyzes electromagnetic interactions between CP antennas and TPS through the reciprocal and transmission line (TL) theories. A method is proposed to design an artificial reflecting surface (ARS) by calculating its optimal equivalent circuit. The designed ARS restores the CP properties of an embedded antenna by substituting its perfect electric conductor (PEC) ground. A dual-band 3/7 GHz CP antenna is designed and fabricated to verify the proposed theoretical method. By loading a double-layer ARS with serpentine loop and serpentine slot units, several negative effects of TPS are mitigated, resulting in resonance depth restoration and AR bandwidth widening. In particular, the 3 dB AR beamwidth of the proposed CP antenna covered by a double-layer TPS is significantly broadened, whose AR beams are widened to 110° on average in the frequency range of 2.91-3.16 GHz and to 65° on average in the frequency range of 6.69-7.22 GHz. The realized CP gains of the antenna are more than 5.0 dBc throughout the working bands.","PeriodicalId":34267,"journal":{"name":"IEEE Open Journal of Antennas and Propagation","volume":"6 5","pages":"1622-1631"},"PeriodicalIF":3.6,"publicationDate":"2025-03-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10999100","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145449316","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 : 2025-03-11DOI: 10.1109/OJAP.2025.3550271
Constant M. A. Niamien
This paper presents a new design concept for improving active antennas’ performances beyond the standard impedance matching technique. The proposed approach expands the mismatch at the antenna-amplifier interface to create a voltage excess, transferred to the matched output receiver using a voltage-type amplifier instead of a power type. Compared with a standard dual-input-output matching, this leads to comparable bandwidth and DC consumption but significantly improves the peak gain, gain-bandwidth-product (GBWP), stability, and noise figure. Experiments with a conventional dipole antenna confirm an improvement factor near two on gain and GBWP. Stability improves by 10°, tending to reach the reference value of 60° phase margin for sound systems. Also, the noise figure significantly decreases by 4.5 dB on average. In addition, the newly introduced performance metric, typically normalized gain-bandwidth-product (NGBWP), dividing GBWP by the average amplifying stage’s gain and the passive antenna’s GBWP, is NGBWP ${=}6.84$ , far higher than the existing works peaking at 2. Finally, the proposed active dipole shows GBWP ${=}2.68$ , which is 15 times the passive dipole. These attractive characteristics make the present approach suitable for most wireless systems.
{"title":"Active Antennas Beyond the Standard Impedance Matching Technique: Concepts and Applications","authors":"Constant M. A. Niamien","doi":"10.1109/OJAP.2025.3550271","DOIUrl":"https://doi.org/10.1109/OJAP.2025.3550271","url":null,"abstract":"This paper presents a new design concept for improving active antennas’ performances beyond the standard impedance matching technique. The proposed approach expands the mismatch at the antenna-amplifier interface to create a voltage excess, transferred to the matched output receiver using a voltage-type amplifier instead of a power type. Compared with a standard dual-input-output matching, this leads to comparable bandwidth and DC consumption but significantly improves the peak gain, gain-bandwidth-product (GBWP), stability, and noise figure. Experiments with a conventional dipole antenna confirm an improvement factor near two on gain and GBWP. Stability improves by 10°, tending to reach the reference value of 60° phase margin for sound systems. Also, the noise figure significantly decreases by 4.5 dB on average. In addition, the newly introduced performance metric, typically normalized gain-bandwidth-product (NGBWP), dividing GBWP by the average amplifying stage’s gain and the passive antenna’s GBWP, is NGBWP <inline-formula> <tex-math>${=}6.84$ </tex-math></inline-formula>, far higher than the existing works peaking at 2. Finally, the proposed active dipole shows GBWP <inline-formula> <tex-math>${=}2.68$ </tex-math></inline-formula>, which is 15 times the passive dipole. These attractive characteristics make the present approach suitable for most wireless systems.","PeriodicalId":34267,"journal":{"name":"IEEE Open Journal of Antennas and Propagation","volume":"6 3","pages":"821-836"},"PeriodicalIF":3.5,"publicationDate":"2025-03-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10922756","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144170917","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 : 2025-03-10DOI: 10.1109/OJAP.2025.3549446
Yihong Su;Yulei Yang;Xian Qi Lin;Yong Fan
With the advent of Internet of Things (IoT) technology, intelligent devices have greatly enhanced people’s daily lives by providing greater convenience, efficiency, and connectivity. In this context, communication between vehicles, as well as between vehicles and satellite navigation systems, base stations, and other infrastructures, is crucial. These communications utilize millimeter wave frequency bands to achieve faster response times and more accurate target tracking and identification. In this paper, the design guidelines of a stacked dual-band (28/35 GHz) substrate integrated waveguide (SIW) slot antenna array are proposed to achieve the optimal aperture reuse ratio and high aperture efficiency. The dual-band array consists of two-layer substrates, and each layer acts as an independent SIW slot antenna array. The upper substrate is composed of nonadjacent SIW slot sub-arrays for the high band operation, while the low band array is located in the lower substrate radiating through the gap between the high band sub-arrays. A dual-band antenna array with an $8times 8$ array in each band is designed and demonstrated as an example, where the center frequencies of the two bands are chosen to be 28 GHz and 35 GHz. The maximum aperture reuse ratio is achieved by the rational array arrangement, and the improvement in aperture efficiency is accomplished by a periodic grid structure. The measured maximum aperture efficiency reaches 55% and 58% in the desired lower and higher bands, respectively. The measured results of the antenna show superior performance, validating the design guidelines of the antenna topology.
{"title":"Design Guidelines of Stacked Dual-Band SIW Slot Array With Optimal Aperture Reuse Ratio and High Aperture Efficiency","authors":"Yihong Su;Yulei Yang;Xian Qi Lin;Yong Fan","doi":"10.1109/OJAP.2025.3549446","DOIUrl":"https://doi.org/10.1109/OJAP.2025.3549446","url":null,"abstract":"With the advent of Internet of Things (IoT) technology, intelligent devices have greatly enhanced people’s daily lives by providing greater convenience, efficiency, and connectivity. In this context, communication between vehicles, as well as between vehicles and satellite navigation systems, base stations, and other infrastructures, is crucial. These communications utilize millimeter wave frequency bands to achieve faster response times and more accurate target tracking and identification. In this paper, the design guidelines of a stacked dual-band (28/35 GHz) substrate integrated waveguide (SIW) slot antenna array are proposed to achieve the optimal aperture reuse ratio and high aperture efficiency. The dual-band array consists of two-layer substrates, and each layer acts as an independent SIW slot antenna array. The upper substrate is composed of nonadjacent SIW slot sub-arrays for the high band operation, while the low band array is located in the lower substrate radiating through the gap between the high band sub-arrays. A dual-band antenna array with an <inline-formula> <tex-math>$8times 8$ </tex-math></inline-formula> array in each band is designed and demonstrated as an example, where the center frequencies of the two bands are chosen to be 28 GHz and 35 GHz. The maximum aperture reuse ratio is achieved by the rational array arrangement, and the improvement in aperture efficiency is accomplished by a periodic grid structure. The measured maximum aperture efficiency reaches 55% and 58% in the desired lower and higher bands, respectively. The measured results of the antenna show superior performance, validating the design guidelines of the antenna topology.","PeriodicalId":34267,"journal":{"name":"IEEE Open Journal of Antennas and Propagation","volume":"6 3","pages":"797-809"},"PeriodicalIF":3.5,"publicationDate":"2025-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10919047","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144170829","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 : 2025-03-10DOI: 10.1109/OJAP.2025.3549922
David Cabornero;Lorena Lozano;Iván González;Álvaro Somolinos;Felipe Cátedra
A new ray-tracing acceleration technique is presented for electromagnetic simulation problems using the Uniform Theory of Diffraction and meshes of planar facets. The innovation involves using relational databases to accurately store spatial information, enabling spatial indexing through space partitioning with R-trees. This technique effectively reduces the computational cost of several critical phases, including the shadowing test. Additionally, there are multiple advantages to utilizing this technology, such as automated memory and disk management along with a query planner that organizes the instructions automatically. Direct rays, multiple reflections, multiple transmissions, simple diffraction, and combinations of these effects have been implemented in PostgreSQL and its spatial library PostGIS. Compared to traditional techniques that employ Angular Z-Buffer acceleration and store information solely in RAM using a low-level language, this approach decreases memory usage by more than 90% in complex scenarios. It also shows a decrease in execution time by more than half when the scenario is sufficiently complex.
{"title":"Application of Relational Databases to the Acceleration of Ray Tracing in High Frequency Asymptotic Techniques","authors":"David Cabornero;Lorena Lozano;Iván González;Álvaro Somolinos;Felipe Cátedra","doi":"10.1109/OJAP.2025.3549922","DOIUrl":"https://doi.org/10.1109/OJAP.2025.3549922","url":null,"abstract":"A new ray-tracing acceleration technique is presented for electromagnetic simulation problems using the Uniform Theory of Diffraction and meshes of planar facets. The innovation involves using relational databases to accurately store spatial information, enabling spatial indexing through space partitioning with R-trees. This technique effectively reduces the computational cost of several critical phases, including the shadowing test. Additionally, there are multiple advantages to utilizing this technology, such as automated memory and disk management along with a query planner that organizes the instructions automatically. Direct rays, multiple reflections, multiple transmissions, simple diffraction, and combinations of these effects have been implemented in PostgreSQL and its spatial library PostGIS. Compared to traditional techniques that employ Angular Z-Buffer acceleration and store information solely in RAM using a low-level language, this approach decreases memory usage by more than 90% in complex scenarios. It also shows a decrease in execution time by more than half when the scenario is sufficiently complex.","PeriodicalId":34267,"journal":{"name":"IEEE Open Journal of Antennas and Propagation","volume":"6 3","pages":"810-820"},"PeriodicalIF":3.5,"publicationDate":"2025-03-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10919085","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144170827","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 : 2025-03-09DOI: 10.1109/OJAP.2025.3568270
Muhammad Noman;Hattan Abutarboush;Khurram K. Qureshi;Adnan Zahid;Farooq A. Tahir;Muhammad Imran;Qammer H. Abbasi
This paper presents a novel dual-mode chiral metasurface (CM) designed to achieve strong circular dichroism (CD) in both transmission and reflection mode within the Ku-band. The proposed dual-mode CM demonstrates CD i.e., an efficient conversion of linearly polarized (LP) electromagnetic (EM) waves into circularly polarized (CP) waves, both within a broader spectrum as well as at single frequencies in both transmission and reflection mode, exhibiting asymmetric transmission (AT) response. This is achieved through a judiciously designed unit cell structure, which eliminates the requirement for intricate supercell configurations or active circuitry. The metasurface comprises a circular ring structure embedded with intelligently placed angle-induced slot and a metallic strip, fabricated using the cost-effective FR-4 substrate. The structure on the front side of the dual-mode CM is replicated on the back side of the substrate with a 90° rotation to achieve a chiral configuration. Under the forward-propagating y-polarized incident wave, the dual-mode CM demonstrates the capability to convert LP wave into right-handed circularly polarized (RHCP) wave at 14.064 GHz. Additionally, in transmission mode, it converts LP waves to left-handed circularly polarized (LHCP) wave over a wider frequency range of 16.60 – 17.03 GHz with AT response. In reflection mode, the dual-mode CM converts LP wave into RHCP wave at 12.048 GHz when subject to x-polarized incident wave propagating in the backward direction.
{"title":"Circular Dichroism and Cross Polarization Conversion Using Chiral Metasurface","authors":"Muhammad Noman;Hattan Abutarboush;Khurram K. Qureshi;Adnan Zahid;Farooq A. Tahir;Muhammad Imran;Qammer H. Abbasi","doi":"10.1109/OJAP.2025.3568270","DOIUrl":"https://doi.org/10.1109/OJAP.2025.3568270","url":null,"abstract":"This paper presents a novel dual-mode chiral metasurface (CM) designed to achieve strong circular dichroism (CD) in both transmission and reflection mode within the Ku-band. The proposed dual-mode CM demonstrates CD i.e., an efficient conversion of linearly polarized (LP) electromagnetic (EM) waves into circularly polarized (CP) waves, both within a broader spectrum as well as at single frequencies in both transmission and reflection mode, exhibiting asymmetric transmission (AT) response. This is achieved through a judiciously designed unit cell structure, which eliminates the requirement for intricate supercell configurations or active circuitry. The metasurface comprises a circular ring structure embedded with intelligently placed angle-induced slot and a metallic strip, fabricated using the cost-effective FR-4 substrate. The structure on the front side of the dual-mode CM is replicated on the back side of the substrate with a 90° rotation to achieve a chiral configuration. Under the forward-propagating y-polarized incident wave, the dual-mode CM demonstrates the capability to convert LP wave into right-handed circularly polarized (RHCP) wave at 14.064 GHz. Additionally, in transmission mode, it converts LP waves to left-handed circularly polarized (LHCP) wave over a wider frequency range of 16.60 – 17.03 GHz with AT response. In reflection mode, the dual-mode CM converts LP wave into RHCP wave at 12.048 GHz when subject to x-polarized incident wave propagating in the backward direction.","PeriodicalId":34267,"journal":{"name":"IEEE Open Journal of Antennas and Propagation","volume":"6 4","pages":"1226-1236"},"PeriodicalIF":3.6,"publicationDate":"2025-03-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10993380","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144831682","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 : 2025-03-09DOI: 10.1109/OJAP.2025.3567968
Ahmed Jasim;Mahdi Moosazadeh;Christophe Fumeaux;Amin Abbosh
A low-profile, high-gain leaky-wave pillbox K-band antenna with mechanical beam scanning is presented. The antenna consists of three layers: one feeding network layer and two radiating layers. A substrate-integrated waveguide wide-angle H-plane horn feed is connected to a one-dimensional reflector using vias rows, forming a closed pillbox reflector to prevent parasitic wave leakage. A simple coaxial feeding port is used to reduce the antenna’s complexity and cost. The middle substrate disk, made from two half-disk substrates with permittivities ${varepsilon}_{r1}{=}2.55$ and ${varepsilon}_{r2}{=}2.20$ , forms the bottom of the radiating structure and is separated from the top substrate layer with periodic leaky-wave radiating elements. Rotating the middle layer by 180° changes the leaky wave’s propagation, and thus shifts the beam direction. The top radiating layer has four sets of patches with different spacings in the disk’s four quadrants. Beam scanning is achieved by rotating the disk to activate each quadrant and thus shift the beam to four distinct elevation angles. Combining the rotation states of the two layers allows wide beam scanning in the elevation direction at eight different angles. Beam scanning in the azimuth direction can be realized using a rotary joint. The design was verified using the transverse resonance method and full wave simulations. A prototype with a size of $340times 320times 5{mathrm {mm}}^{3}$ was built and tested in the 19.5 – 20.5 GHz frequency band, showing a beam scanning range of $0- 43^{circ }$ , a realized gain of 25.7 dBi, −4 dB crossover levels, −27 dB cross-polarization level, and side lobe levels below −10 dB.
{"title":"Mechanically Scanned Leaky-Wave Pillbox K-Band Antenna With Dual Radiating Layers Using Variable Permittivity Substrate and Nonuniform Patches","authors":"Ahmed Jasim;Mahdi Moosazadeh;Christophe Fumeaux;Amin Abbosh","doi":"10.1109/OJAP.2025.3567968","DOIUrl":"https://doi.org/10.1109/OJAP.2025.3567968","url":null,"abstract":"A low-profile, high-gain leaky-wave pillbox K-band antenna with mechanical beam scanning is presented. The antenna consists of three layers: one feeding network layer and two radiating layers. A substrate-integrated waveguide wide-angle H-plane horn feed is connected to a one-dimensional reflector using vias rows, forming a closed pillbox reflector to prevent parasitic wave leakage. A simple coaxial feeding port is used to reduce the antenna’s complexity and cost. The middle substrate disk, made from two half-disk substrates with permittivities <inline-formula> <tex-math>${varepsilon}_{r1}{=}2.55$ </tex-math></inline-formula> and <inline-formula> <tex-math>${varepsilon}_{r2}{=}2.20$ </tex-math></inline-formula>, forms the bottom of the radiating structure and is separated from the top substrate layer with periodic leaky-wave radiating elements. Rotating the middle layer by 180° changes the leaky wave’s propagation, and thus shifts the beam direction. The top radiating layer has four sets of patches with different spacings in the disk’s four quadrants. Beam scanning is achieved by rotating the disk to activate each quadrant and thus shift the beam to four distinct elevation angles. Combining the rotation states of the two layers allows wide beam scanning in the elevation direction at eight different angles. Beam scanning in the azimuth direction can be realized using a rotary joint. The design was verified using the transverse resonance method and full wave simulations. A prototype with a size of <inline-formula> <tex-math>$340times 320times 5{mathrm {mm}}^{3}$ </tex-math></inline-formula> was built and tested in the 19.5 – 20.5 GHz frequency band, showing a beam scanning range of <inline-formula> <tex-math>$0- 43^{circ }$ </tex-math></inline-formula>, a realized gain of 25.7 dBi, −4 dB crossover levels, −27 dB cross-polarization level, and side lobe levels below −10 dB.","PeriodicalId":34267,"journal":{"name":"IEEE Open Journal of Antennas and Propagation","volume":"6 4","pages":"1188-1198"},"PeriodicalIF":3.6,"publicationDate":"2025-03-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10992681","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144831678","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 : 2025-03-08DOI: 10.1109/OJAP.2025.3568139
Yilin Ji;Chunhui Li;Wei Fan
The prefaded signal synthesis (PFS) is a popular channel emulation method used for multiple-input multiple-output over-the-air (MIMO-OTA) testing with the multi-probe anechoic chamber (MPAC) setup. It aims to synthesize the second-order statistics of a target propagation channel in terms of the spatial and temporal correlation. The emulated spatial and temporal correlation is evaluated in a confined volume (test zone) enclosing the device-under-test (DUT). In the industry, it has been often asked about (i) the minimum sufficient spatial sampling density within the test zone when solving probe weights, and (ii) the effect of the antenna radiation pattern of different DUT’s on the emulated channel. In this paper, we aim to address those questions analytically from the perspective of the power spectral density function in the direction and Doppler frequency domain, i.e., the Fourier dual of the spatial and temporal correlation function. Moreover, we use the same Fourier duality to study (i) the root cause of the empirical statistics being different from the statistical expectation for a single channel realization, and (ii) the applicability and effectiveness of two spectral operations, namely the decorrelation and the whitening operation, on improving the empirical statistics for the emulated channel.
{"title":"Fourier Analysis of the Prefaded Signal Synthesis in MPAC Setup","authors":"Yilin Ji;Chunhui Li;Wei Fan","doi":"10.1109/OJAP.2025.3568139","DOIUrl":"https://doi.org/10.1109/OJAP.2025.3568139","url":null,"abstract":"The prefaded signal synthesis (PFS) is a popular channel emulation method used for multiple-input multiple-output over-the-air (MIMO-OTA) testing with the multi-probe anechoic chamber (MPAC) setup. It aims to synthesize the second-order statistics of a target propagation channel in terms of the spatial and temporal correlation. The emulated spatial and temporal correlation is evaluated in a confined volume (test zone) enclosing the device-under-test (DUT). In the industry, it has been often asked about (i) the minimum sufficient spatial sampling density within the test zone when solving probe weights, and (ii) the effect of the antenna radiation pattern of different DUT’s on the emulated channel. In this paper, we aim to address those questions analytically from the perspective of the power spectral density function in the direction and Doppler frequency domain, i.e., the Fourier dual of the spatial and temporal correlation function. Moreover, we use the same Fourier duality to study (i) the root cause of the empirical statistics being different from the statistical expectation for a single channel realization, and (ii) the applicability and effectiveness of two spectral operations, namely the decorrelation and the whitening operation, on improving the empirical statistics for the emulated channel.","PeriodicalId":34267,"journal":{"name":"IEEE Open Journal of Antennas and Propagation","volume":"6 4","pages":"1213-1225"},"PeriodicalIF":3.6,"publicationDate":"2025-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10993413","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144831718","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}
To explore the anisotropic nature and improve computational efficiency, eigenvalue (EV-) analysis is adopted to implement the transfer matrix method (TMM), abbreviated as EV-TMM, enabling the accurate capture of propagation coefficients with different polarizations under the inhomogeneous multi-layer background. When the plane waves carrying electromagnetic information enters an anisotropic medium from air, it will excite four beams with different energies and propagation directions in the medium. Starting from the anisotropic Maxwell’s equations, the governing equation in matrix form is constructed from constitutive relations of the electromagnetic field. When facing different anisotropy, the eigenvalues along the vertical direction are obtained calculating the partial differential equation. Subsequently, given the electric intensity in the co-polarization direction, other relevant components can be easily acquired based on the aforementioned governing equation and Faraday’s law. For characterizing the data connections between different layer media, the tangential conditions of electric and magnetic fields are applied to construct the transfer matrix for the multi-layer media. To verify the reliability of EV-TMM, the commercial software COMSOL, the finite-difference time-domain (FDTD) method, and the conventional TMM (C-TMM) are selected as benchmarks for rigorous validation through two numerical experiments under different plane wave modes. EV-TMM saves at least 51.3% of memory and 57.0% of CPU computation time when analyzing various anisotropic structures. Finally, we utilize the amplitude modulation technology to change the value at the transverse vectors and obtain color images of the propagation coefficient in subsurface multi-layer media by EV-TMM, thus achieving the analysis for geological structure.
{"title":"Efficient Calculation of Propagation Coefficients in Anisotropic Media Through Transfer Matrix Method Based on Eigenvalue Analysis","authors":"Jiuyang Fan;Zhixiang Huang;Xiaoli Feng;Yuxian Zhang","doi":"10.1109/OJAP.2025.3568033","DOIUrl":"https://doi.org/10.1109/OJAP.2025.3568033","url":null,"abstract":"To explore the anisotropic nature and improve computational efficiency, eigenvalue (EV-) analysis is adopted to implement the transfer matrix method (TMM), abbreviated as EV-TMM, enabling the accurate capture of propagation coefficients with different polarizations under the inhomogeneous multi-layer background. When the plane waves carrying electromagnetic information enters an anisotropic medium from air, it will excite four beams with different energies and propagation directions in the medium. Starting from the anisotropic Maxwell’s equations, the governing equation in matrix form is constructed from constitutive relations of the electromagnetic field. When facing different anisotropy, the eigenvalues along the vertical direction are obtained calculating the partial differential equation. Subsequently, given the electric intensity in the co-polarization direction, other relevant components can be easily acquired based on the aforementioned governing equation and Faraday’s law. For characterizing the data connections between different layer media, the tangential conditions of electric and magnetic fields are applied to construct the transfer matrix for the multi-layer media. To verify the reliability of EV-TMM, the commercial software COMSOL, the finite-difference time-domain (FDTD) method, and the conventional TMM (C-TMM) are selected as benchmarks for rigorous validation through two numerical experiments under different plane wave modes. EV-TMM saves at least 51.3% of memory and 57.0% of CPU computation time when analyzing various anisotropic structures. Finally, we utilize the amplitude modulation technology to change the value at the transverse vectors and obtain color images of the propagation coefficient in subsurface multi-layer media by EV-TMM, thus achieving the analysis for geological structure.","PeriodicalId":34267,"journal":{"name":"IEEE Open Journal of Antennas and Propagation","volume":"6 4","pages":"1199-1212"},"PeriodicalIF":3.6,"publicationDate":"2025-03-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10993419","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144831684","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}
An optically transparent single-layer dual-frequency dual-polarization metasurface operating at 28 GHz and 38 GHz is proposed to enhance millimeter-wave transmission through glass. The unit cell design of the proposed metasurface has three distinct pattern types: square annular, Jerusalem cross, and circular. The former pattern can independently control the low-frequency resonance, while the latter two can control the high-frequency resonance. The proposed metasurface can achieve a large incident angle of 60 degrees for electromagnetic waves in TE and TM polarizations. After the metal layer of the proposed metasurface is meshed, the transparency of the metasurface is significantly improved. The meshed metasurface can be coated on the glass back cover of a smartphone to improve the performance of the millimeter-wave phased array antenna system under the glass back cover without affecting the aesthetics of the smartphone back cover. The prototype of a dual-band patch phased array antenna with the metasurface-coated glass superstrate is fabricated and tested as proof of concept. The experimental results are good and the effectiveness of the proposed metasurface is well verified.
{"title":"Optically Transparent Single-Layer Dual-Frequency Dual-Polarization Metasurface Applied in Close Proximity to Smartphone Millimeter-Wave Phased Array Antenna Systems","authors":"Wen Fu;Igor Syrytsin;Rocio Rodriguez Cano;Peiye Liu;Andrey Kobyakov;Gert Frølund Pedersen;Shuai Zhang","doi":"10.1109/OJAP.2025.3549085","DOIUrl":"https://doi.org/10.1109/OJAP.2025.3549085","url":null,"abstract":"An optically transparent single-layer dual-frequency dual-polarization metasurface operating at 28 GHz and 38 GHz is proposed to enhance millimeter-wave transmission through glass. The unit cell design of the proposed metasurface has three distinct pattern types: square annular, Jerusalem cross, and circular. The former pattern can independently control the low-frequency resonance, while the latter two can control the high-frequency resonance. The proposed metasurface can achieve a large incident angle of 60 degrees for electromagnetic waves in TE and TM polarizations. After the metal layer of the proposed metasurface is meshed, the transparency of the metasurface is significantly improved. The meshed metasurface can be coated on the glass back cover of a smartphone to improve the performance of the millimeter-wave phased array antenna system under the glass back cover without affecting the aesthetics of the smartphone back cover. The prototype of a dual-band patch phased array antenna with the metasurface-coated glass superstrate is fabricated and tested as proof of concept. The experimental results are good and the effectiveness of the proposed metasurface is well verified.","PeriodicalId":34267,"journal":{"name":"IEEE Open Journal of Antennas and Propagation","volume":"6 3","pages":"789-796"},"PeriodicalIF":3.5,"publicationDate":"2025-03-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10916750","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144170830","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 the design, fabrication, and measurement of a $4times 4$ patch array antenna for radar-based obstacle detection systems in railway transportation. Sidelobe suppression is achieved through amplitude tapering of sub-array elements in the E-plane and asymmetric power dividers in the feed network for the H-plane. The array antenna is framed by a coplanar ground conductor to further reduce sidelobes and fed by a coplanar waveguide port for enhanced impedance bandwidth. The proposed antenna offers an impedance bandwidth from 9.13 GHz to 9.76 GHz (6.3%) and a broadside gain of 18.15 dBi at the center frequency of 9.55 GHz. Sidelobe suppression exceeds 12.22 dB and 19.06 dB in the E- and H-plane, respectively. The 3-dB beamwidth is 17° in the E-plane and 16° in the H-plane with simulated radiation efficiency of 85%. A prototype was fabricated and measured, with sensitivity analysis conducted to assess performance variations due to fabrication tolerances and measurement fixture effects. To validate system performance, antenna prototypes were integrated into a frequency-modulated continuous wave radar system and tested in a realistic railway environment. The system successfully detected a truck crossing a railway track at approximately 1,260 meters, confirming the antenna’s suitability for radar-based obstacle detection in railway transportation.
{"title":"A Wideband 4×4 Patch Array Antenna With Low Sidelobes for Radar-Based Obstacle Detection in Railway Transportation","authors":"Thipamas Phakaew;Tiwat Pongthavornkamol;Danai Torrungrueng;Thomas Dallmann;Suramate Chalermwisutkul","doi":"10.1109/OJAP.2025.3548112","DOIUrl":"https://doi.org/10.1109/OJAP.2025.3548112","url":null,"abstract":"This paper presents the design, fabrication, and measurement of a <inline-formula> <tex-math>$4times 4$ </tex-math></inline-formula> patch array antenna for radar-based obstacle detection systems in railway transportation. Sidelobe suppression is achieved through amplitude tapering of sub-array elements in the E-plane and asymmetric power dividers in the feed network for the H-plane. The array antenna is framed by a coplanar ground conductor to further reduce sidelobes and fed by a coplanar waveguide port for enhanced impedance bandwidth. The proposed antenna offers an impedance bandwidth from 9.13 GHz to 9.76 GHz (6.3%) and a broadside gain of 18.15 dBi at the center frequency of 9.55 GHz. Sidelobe suppression exceeds 12.22 dB and 19.06 dB in the E- and H-plane, respectively. The 3-dB beamwidth is 17° in the E-plane and 16° in the H-plane with simulated radiation efficiency of 85%. A prototype was fabricated and measured, with sensitivity analysis conducted to assess performance variations due to fabrication tolerances and measurement fixture effects. To validate system performance, antenna prototypes were integrated into a frequency-modulated continuous wave radar system and tested in a realistic railway environment. The system successfully detected a truck crossing a railway track at approximately 1,260 meters, confirming the antenna’s suitability for radar-based obstacle detection in railway transportation.","PeriodicalId":34267,"journal":{"name":"IEEE Open Journal of Antennas and Propagation","volume":"6 3","pages":"774-788"},"PeriodicalIF":3.5,"publicationDate":"2025-03-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10912488","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144170831","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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