Pub Date : 2024-10-24DOI: 10.1109/OJAP.2024.3486248
Josef Pokorny;Premysl Dohnal;Petr Marcon
This article discusses the basic principles of concentrating the radiated near non-radiant magnetic field by changing the angle of the winding sector of the spiral coils designed on a substrate for a standard PCB (printed circuit board). The relevant principles include: 1) Changing the shape and design of the movable inner part of the coil winding; together with the static part, the moving item can form a concentrated magnetic field in space, thus creating a magnetic vector. 2) The $2times 2$ matrix of these coils comprises individual resonators changing the shape of the magnetic field according to the shape, distance, and position of the receiver. Thus, the concentrated individual vectors of the field are formed by the current amplitude, azimuth, and elevation of the individual coils. Using a spare electrical circuit, we implemented the entire concept relying on the shape of the coils. This method is materialized on a hardware prototype.
{"title":"Wireless Multi-Coil Transmission With a Rotating Part of the Internal Winding","authors":"Josef Pokorny;Premysl Dohnal;Petr Marcon","doi":"10.1109/OJAP.2024.3486248","DOIUrl":"https://doi.org/10.1109/OJAP.2024.3486248","url":null,"abstract":"This article discusses the basic principles of concentrating the radiated near non-radiant magnetic field by changing the angle of the winding sector of the spiral coils designed on a substrate for a standard PCB (printed circuit board). The relevant principles include: 1) Changing the shape and design of the movable inner part of the coil winding; together with the static part, the moving item can form a concentrated magnetic field in space, thus creating a magnetic vector. 2) The <inline-formula> <tex-math>$2times 2$ </tex-math></inline-formula> matrix of these coils comprises individual resonators changing the shape of the magnetic field according to the shape, distance, and position of the receiver. Thus, the concentrated individual vectors of the field are formed by the current amplitude, azimuth, and elevation of the individual coils. Using a spare electrical circuit, we implemented the entire concept relying on the shape of the coils. This method is materialized on a hardware prototype.","PeriodicalId":34267,"journal":{"name":"IEEE Open Journal of Antennas and Propagation","volume":"6 1","pages":"163-170"},"PeriodicalIF":3.5,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10734347","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143107077","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 : 2024-10-24DOI: 10.1109/OJAP.2024.3485817
Jin Hu;Emrah Sever;Omid Babazadeh;Ian Jeffrey;Vladimir Okhmatovski;Constantine Sideris
An H-matrix accelerated direct solver employing the high-order Chebyshev-based Boundary Integral Equation (CBIE) method has been formulated, tested, and profiled for performance on high contrast dielectric materials and electrically large perfect electric conductor objects. The matrix fill performance of the CBIE proves to be fast for small to moderately sized problems compared to its counterparts, e.g., the locally corrected Nyström (LCN) method, due to the way it handles the singularities by means of a global change of variable method. However, in the case of electrically large scattering problems, the matrix fill and factorization still dominate the solution time when using a direct solution approach. To address this issue, an H-Matrix framework is employed, effectively resolving the challenge and establishing the CBIE as a competitive high-order method for solving scattering problems with poorly conditioned matrix equations. The efficacy of this approach is demonstrated through extensive numerical results, showcasing its robustness to problems that are electrically large, near physical resonances, or that have large dielectric permittivities. The capability of the proposed solver for handling arbitrary geometries is also demonstrated by considering various scattering examples from complex CAD models.
{"title":"H-Matrix Accelerated Direct Matrix Solver for Maxwell’s Equations Using the Chebyshev-Based Nyström Boundary Integral Equation Method","authors":"Jin Hu;Emrah Sever;Omid Babazadeh;Ian Jeffrey;Vladimir Okhmatovski;Constantine Sideris","doi":"10.1109/OJAP.2024.3485817","DOIUrl":"https://doi.org/10.1109/OJAP.2024.3485817","url":null,"abstract":"An H-matrix accelerated direct solver employing the high-order Chebyshev-based Boundary Integral Equation (CBIE) method has been formulated, tested, and profiled for performance on high contrast dielectric materials and electrically large perfect electric conductor objects. The matrix fill performance of the CBIE proves to be fast for small to moderately sized problems compared to its counterparts, e.g., the locally corrected Nyström (LCN) method, due to the way it handles the singularities by means of a global change of variable method. However, in the case of electrically large scattering problems, the matrix fill and factorization still dominate the solution time when using a direct solution approach. To address this issue, an H-Matrix framework is employed, effectively resolving the challenge and establishing the CBIE as a competitive high-order method for solving scattering problems with poorly conditioned matrix equations. The efficacy of this approach is demonstrated through extensive numerical results, showcasing its robustness to problems that are electrically large, near physical resonances, or that have large dielectric permittivities. The capability of the proposed solver for handling arbitrary geometries is also demonstrated by considering various scattering examples from complex CAD models.","PeriodicalId":34267,"journal":{"name":"IEEE Open Journal of Antennas and Propagation","volume":"6 1","pages":"171-180"},"PeriodicalIF":3.5,"publicationDate":"2024-10-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10734393","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143107001","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 : 2024-10-18DOI: 10.1109/OJAP.2024.3483277
Ala Alemaryeen;Sima Noghanian
Implanted wireless biomedical devices represent a significant advancement in medical technology, offering continuous monitoring and targeted therapy. Antenna design for these devices requires careful modeling to ensure efficiency and safety, addressing challenges such as tissue heating and compliance with safety regulations. Specific absorption rate (SAR) analysis, commonly used to ensure safety, often overlooks factors that influence tissue temperature and heat transfer. Understanding heat generation within tissues due to factors like location, orientation, and radiation power is crucial for optimizing device performance. Simulation-driven design and additional computational and experimental studies are essential for patient safety and effective device evaluation. This article focuses on examining tissue temperature elevation near implanted antennas, specifically a simple dipole antenna, to identify design parameters that significantly impact thermal performance. Key parameters include body phantom type and size, thermal boundary conditions, bioheat model parameters, implantation depth, antenna orientation, and input power. The study aims to provide guidelines for designers on optimizing antenna parameters to accurately predict and manage biological tissue heating. It was found that the size of the phantom, blood perfusion, volume thermal losses, antenna orientation, and input power constitute the major effects on tissue heating. An experimental setup was used to help understand the effect of the antenna’s input power on the temperature distribution in the surrounding high dielectric constant material. A dipole antenna was inserted inside a distilled water tank, and the temperature was measured at three reference points surrounding the antenna. Simulation and measurement results were in good agreement supporting the proposed methodology.
{"title":"Electromagnetic and Thermal Co-Analysis of an Implanted Dipole Antenna","authors":"Ala Alemaryeen;Sima Noghanian","doi":"10.1109/OJAP.2024.3483277","DOIUrl":"https://doi.org/10.1109/OJAP.2024.3483277","url":null,"abstract":"Implanted wireless biomedical devices represent a significant advancement in medical technology, offering continuous monitoring and targeted therapy. Antenna design for these devices requires careful modeling to ensure efficiency and safety, addressing challenges such as tissue heating and compliance with safety regulations. Specific absorption rate (SAR) analysis, commonly used to ensure safety, often overlooks factors that influence tissue temperature and heat transfer. Understanding heat generation within tissues due to factors like location, orientation, and radiation power is crucial for optimizing device performance. Simulation-driven design and additional computational and experimental studies are essential for patient safety and effective device evaluation. This article focuses on examining tissue temperature elevation near implanted antennas, specifically a simple dipole antenna, to identify design parameters that significantly impact thermal performance. Key parameters include body phantom type and size, thermal boundary conditions, bioheat model parameters, implantation depth, antenna orientation, and input power. The study aims to provide guidelines for designers on optimizing antenna parameters to accurately predict and manage biological tissue heating. It was found that the size of the phantom, blood perfusion, volume thermal losses, antenna orientation, and input power constitute the major effects on tissue heating. An experimental setup was used to help understand the effect of the antenna’s input power on the temperature distribution in the surrounding high dielectric constant material. A dipole antenna was inserted inside a distilled water tank, and the temperature was measured at three reference points surrounding the antenna. Simulation and measurement results were in good agreement supporting the proposed methodology.","PeriodicalId":34267,"journal":{"name":"IEEE Open Journal of Antennas and Propagation","volume":"5 6","pages":"1539-1550"},"PeriodicalIF":3.5,"publicationDate":"2024-10-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10722868","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142679341","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 : 2024-10-16DOI: 10.1109/OJAP.2024.3481991
Edward A. Ball;Sumin David Joseph
The prototype design and testing of an E band mmWave Time Modulated Array (TMA) is presented. The PCB based array has a 3 dB RF bandwidth of 71-73 GHz and a peak gain of −2 dBi on the first harmonic steered beam. The TMA second harmonic beam gain is within 0.9 dB of a conventional phase-shifter based array, in a like-for-like theoretical comparison. An array gain of +11.5 dBi is predicted for a full on-chip implementation. Good agreement between theoretical and prototype measured gains and array patterns are reported. Beam steering and phase correction are implemented using an FPGA, requiring only 2 digital lines per array element. A dedicated, bespoke GaAs mmWave Monolithic Integrated Circuit (MMIC) to realize the TMA is presented. A key feature of the MMIC is a sub 400 ps phase inversion switch. The MMICs provide a measured average gain of 4.4 dB and draw 61.2 mW. The TMA is demonstrated steering the first harmonic beam to +/−12 degrees and the second harmonic beam to +/−30 degrees. The maxim steer possible is +/−16 degrees for the first and +/−35 degrees for the second harmonic beams. The full hardware demonstrator platform is presented and laboratory measurements provided, confirming good operation of the array compared to theory. Our work is the first demonstration of a steerable TX TMA operating in E band.
{"title":"A mmWave Transmitting Time Modulated Array Using Bespoke GaAs Integrated Circuits—Prototype Design and Laboratory Trials at 73 GHz","authors":"Edward A. Ball;Sumin David Joseph","doi":"10.1109/OJAP.2024.3481991","DOIUrl":"https://doi.org/10.1109/OJAP.2024.3481991","url":null,"abstract":"The prototype design and testing of an E band mmWave Time Modulated Array (TMA) is presented. The PCB based array has a 3 dB RF bandwidth of 71-73 GHz and a peak gain of −2 dBi on the first harmonic steered beam. The TMA second harmonic beam gain is within 0.9 dB of a conventional phase-shifter based array, in a like-for-like theoretical comparison. An array gain of +11.5 dBi is predicted for a full on-chip implementation. Good agreement between theoretical and prototype measured gains and array patterns are reported. Beam steering and phase correction are implemented using an FPGA, requiring only 2 digital lines per array element. A dedicated, bespoke GaAs mmWave Monolithic Integrated Circuit (MMIC) to realize the TMA is presented. A key feature of the MMIC is a sub 400 ps phase inversion switch. The MMICs provide a measured average gain of 4.4 dB and draw 61.2 mW. The TMA is demonstrated steering the first harmonic beam to +/−12 degrees and the second harmonic beam to +/−30 degrees. The maxim steer possible is +/−16 degrees for the first and +/−35 degrees for the second harmonic beams. The full hardware demonstrator platform is presented and laboratory measurements provided, confirming good operation of the array compared to theory. Our work is the first demonstration of a steerable TX TMA operating in E band.","PeriodicalId":34267,"journal":{"name":"IEEE Open Journal of Antennas and Propagation","volume":"6 1","pages":"144-162"},"PeriodicalIF":3.5,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10720082","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143106970","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 : 2024-10-09DOI: 10.1109/OJAP.2024.3477318
Marzieh Mehri Dehnavi;Jean-Jacques Laurin
This work proposes a phase-only synthesis technique for shaping the beam of a circularly polarized dual-reflector antenna with a subreflector consisting of a reflectarray and a main parabolic reflector. The proposed technique exploits the element patterns of each reflectarray unit cell embedded in the whole system, including a feed horn, a reflectarray, and a main reflector. By using a penalty function that forces only the fitting of the desired and obtained patterns, the algorithm leads to a quasi-random phase distribution on the reflectarray and a poor radiation pattern. A term for minimizing the Laplacian of the phase distribution is added to the penalty function to force a smoothly varying phase distribution on the reflectarray. This modification provides more stable results and yields patterns with desired shapes and regular contours. The beam shaping capability of the algorithm is demonstrated with simulations of a 100-element reconfigurable circularly polarized reflectarray, by controlling independently the 10 dB beamwidth of the antenna in two orthogonal planes The algorithm is also validated experimentally. Beamwidth accuracies vary from 0 to 2.15 degrees.
{"title":"Beam Shaping of a Dual-Reflector Antenna Using a Reflectarray as Subreflector and Embedded Unit Cell Patterns","authors":"Marzieh Mehri Dehnavi;Jean-Jacques Laurin","doi":"10.1109/OJAP.2024.3477318","DOIUrl":"https://doi.org/10.1109/OJAP.2024.3477318","url":null,"abstract":"This work proposes a phase-only synthesis technique for shaping the beam of a circularly polarized dual-reflector antenna with a subreflector consisting of a reflectarray and a main parabolic reflector. The proposed technique exploits the element patterns of each reflectarray unit cell embedded in the whole system, including a feed horn, a reflectarray, and a main reflector. By using a penalty function that forces only the fitting of the desired and obtained patterns, the algorithm leads to a quasi-random phase distribution on the reflectarray and a poor radiation pattern. A term for minimizing the Laplacian of the phase distribution is added to the penalty function to force a smoothly varying phase distribution on the reflectarray. This modification provides more stable results and yields patterns with desired shapes and regular contours. The beam shaping capability of the algorithm is demonstrated with simulations of a 100-element reconfigurable circularly polarized reflectarray, by controlling independently the 10 dB beamwidth of the antenna in two orthogonal planes The algorithm is also validated experimentally. Beamwidth accuracies vary from 0 to 2.15 degrees.","PeriodicalId":34267,"journal":{"name":"IEEE Open Journal of Antennas and Propagation","volume":"6 1","pages":"133-143"},"PeriodicalIF":3.5,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10711861","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143106973","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 : 2024-10-07DOI: 10.1109/OJAP.2024.3474770
Ahmed Hosameldin Khadrawy;Ahmed Abdelmottaleb Omar
This paper proposes a transparent wideband microwave absorber by integrating Indium Tin Oxide (ITO) with glass in order to achieve both high microwave absorption and optical transparency. The design is constructed from three layers of glass substrate with etched ITO with different sheet resistance on each layer. The absorber features a combination of high dielectric constant material to accomplish the low-profile design and matching layer to achieve wide absorption bandwidth. The absorber demonstrates 115.64% fractional bandwidth from 3.48 GHz to 13.02 GHz with a structure thickness of 0.077 $lambda_{min}$ , where $lambda_{min}$ is the free-space wavelength at the lowest operating frequency. The proposed absorber design shows wide absorption bandwidth with a low profile, which outperforms the reported designs in the literature. The development process of the absorber is detailed, showcasing the evolution from a single-layer to a triple-layer design, addressing challenges in fabrication and enhancing performance. The absorber’s effectiveness is validated through simulations and measurements of a fabricated prototype, highlighting its potential in applications requiring both microwave absorption and optical transparency.
{"title":"Transparent Low-Profile and Wideband ITO-Glass Microwave Absorber","authors":"Ahmed Hosameldin Khadrawy;Ahmed Abdelmottaleb Omar","doi":"10.1109/OJAP.2024.3474770","DOIUrl":"https://doi.org/10.1109/OJAP.2024.3474770","url":null,"abstract":"This paper proposes a transparent wideband microwave absorber by integrating Indium Tin Oxide (ITO) with glass in order to achieve both high microwave absorption and optical transparency. The design is constructed from three layers of glass substrate with etched ITO with different sheet resistance on each layer. The absorber features a combination of high dielectric constant material to accomplish the low-profile design and matching layer to achieve wide absorption bandwidth. The absorber demonstrates 115.64% fractional bandwidth from 3.48 GHz to 13.02 GHz with a structure thickness of 0.077 <inline-formula> <tex-math>$lambda_{min}$ </tex-math></inline-formula>, where <inline-formula> <tex-math>$lambda_{min}$ </tex-math></inline-formula> is the free-space wavelength at the lowest operating frequency. The proposed absorber design shows wide absorption bandwidth with a low profile, which outperforms the reported designs in the literature. The development process of the absorber is detailed, showcasing the evolution from a single-layer to a triple-layer design, addressing challenges in fabrication and enhancing performance. The absorber’s effectiveness is validated through simulations and measurements of a fabricated prototype, highlighting its potential in applications requiring both microwave absorption and optical transparency.","PeriodicalId":34267,"journal":{"name":"IEEE Open Journal of Antennas and Propagation","volume":"6 1","pages":"127-132"},"PeriodicalIF":3.5,"publicationDate":"2024-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10706111","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143107074","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-30DOI: 10.1109/OJAP.2024.3470843
Jun Ma;Fuchang Chen;Kairan Xiang
In this paper, a waveguide reflectionless filtering antenna array with high selectivity is proposed. Instead of reflecting the out-of-band signal back to the source, the proposed antenna array dissipates the energy through a lossy network, which can reduce the interference to the former stage. The prototype circuit of the reflectionless filtering antenna array based on the complementary duplex theory is established, consisting of a bandpass network and a bandstop network, whose responses are completely complementary. High selectivity is achieved by introducing non-resonating nodes (NRNs) and configuring the transmission zeros (TZs) of the bandpass network and the reflection zeros (RZs) of the bandstop network to be set at the same frequency. The synthesis of the prototype circuit is given and a fourth-order reflectionless filtering antenna array is designed and fabricated to verify the design method. Two TZs are generated at 9.62 GHz and 10.4 GHz, leading to an out-of-band suppression of more than 23 dB. The measured $|S_{11}|$ is less than −10 dB from 8.3 GHz to 12 GHz, providing a wideband reflectionless filtering response with high selectivity and high gain.
{"title":"X-Band Waveguide Reflectionless Filtering Antenna Array With High Selectivity","authors":"Jun Ma;Fuchang Chen;Kairan Xiang","doi":"10.1109/OJAP.2024.3470843","DOIUrl":"https://doi.org/10.1109/OJAP.2024.3470843","url":null,"abstract":"In this paper, a waveguide reflectionless filtering antenna array with high selectivity is proposed. Instead of reflecting the out-of-band signal back to the source, the proposed antenna array dissipates the energy through a lossy network, which can reduce the interference to the former stage. The prototype circuit of the reflectionless filtering antenna array based on the complementary duplex theory is established, consisting of a bandpass network and a bandstop network, whose responses are completely complementary. High selectivity is achieved by introducing non-resonating nodes (NRNs) and configuring the transmission zeros (TZs) of the bandpass network and the reflection zeros (RZs) of the bandstop network to be set at the same frequency. The synthesis of the prototype circuit is given and a fourth-order reflectionless filtering antenna array is designed and fabricated to verify the design method. Two TZs are generated at 9.62 GHz and 10.4 GHz, leading to an out-of-band suppression of more than 23 dB. The measured <inline-formula> <tex-math>$|S_{11}|$ </tex-math></inline-formula> is less than −10 dB from 8.3 GHz to 12 GHz, providing a wideband reflectionless filtering response with high selectivity and high gain.","PeriodicalId":34267,"journal":{"name":"IEEE Open Journal of Antennas and Propagation","volume":"6 1","pages":"120-126"},"PeriodicalIF":3.5,"publicationDate":"2024-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10700742","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143107076","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-30DOI: 10.1109/OJAP.2024.3470209
Youquan Wen;Sai-Wai Wong;Chunlin Ji;Ruopeng Liu;Yejun He
Traditional multi-layer frequency selective absorbers (FSAs) with antenna circuit suffer from inter-layer interference, which can adversely affect the in-band frequency bandwidth of wireless communication (fractional bandwidth FBW <20%> $0.22lambda _{0}$ . Simulated and measured results demonstrate the in-band FBW of 65.06% for wireless communication (2.8–5.5 GHz which is much wider than those reported FSAs with antenna circuit, e.g., FBW<20%) for two polarizations, with isolation less than −15 dB. Furthermore, the structure achieves impressive absorption performance, with radar cross-section reduction (RCSR) of 10 dB from 2.8 to 23 GHz (FBW=156.6%), and stable basic RCSR up to an oblique incidence of 30°.
{"title":"A Hybrid Frequency Selective Absorber With Dual-Polarized Wireless Communication and Ultra-Wideband Absorption","authors":"Youquan Wen;Sai-Wai Wong;Chunlin Ji;Ruopeng Liu;Yejun He","doi":"10.1109/OJAP.2024.3470209","DOIUrl":"https://doi.org/10.1109/OJAP.2024.3470209","url":null,"abstract":"Traditional multi-layer frequency selective absorbers (FSAs) with antenna circuit suffer from inter-layer interference, which can adversely affect the in-band frequency bandwidth of wireless communication (fractional bandwidth FBW <20%> <tex-math>$0.22lambda _{0}$ </tex-math></inline-formula>. Simulated and measured results demonstrate the in-band FBW of 65.06% for wireless communication (2.8–5.5 GHz which is much wider than those reported FSAs with antenna circuit, e.g., FBW<20%) for two polarizations, with isolation less than −15 dB. Furthermore, the structure achieves impressive absorption performance, with radar cross-section reduction (RCSR) of 10 dB from 2.8 to 23 GHz (FBW=156.6%), and stable basic RCSR up to an oblique incidence of 30°.","PeriodicalId":34267,"journal":{"name":"IEEE Open Journal of Antennas and Propagation","volume":"6 1","pages":"110-119"},"PeriodicalIF":3.5,"publicationDate":"2024-09-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10699372","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143107075","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-09-27DOI: 10.1109/OJAP.2024.3469271
Lisa Berretti;Renaud Loison;Esteban Menargues;Lucas Polo-López;Giovanni Toso;María García-Vigueras
A new type of beamforming network (BFN) based on three-dimensional (3D) discrete lenses is introduced and numerically analyzed in this paper as an antenna system capable of generating multiple beams within a large Field-of-View (FoV). To enhance scanning capabilities, these lenses have their back part and associated feed array magnified relative to the front part. It is also shown that the radiating elements constituting the front part of the lens, due to the shape of their element factor, tend to limit the pointing direction of the overall antenna pattern, but their influence decreases as the lens dimension. Accordingly, a large front array is chosen to scan wide angles and mitigate this limitation. For the preliminary dimensioning and design of the entire BFN, a Geometrical Optics (GO) technique is employed. Subsequently, a rigorous methodology exploiting boundary conditions in the planes of symmetry is implemented to simulate the full-wave behavior of the front array of the lens, which is challenging due to limited computational resources for large arrays. This methodology, which also exploits the even/odd concept, is validated using a small array as a test case. By employing both the GO technique and rigorous full-wave analysis, it is numerically verified that this type of lens system can produce beams pointing up to 70° from the boresight direction while maintaining good levels of cross-polar discrimination in all azimuthal planes. Additionally, numerical evidence shows that these magnified lenses can increase their FoV compared to lenses with equal back and front sizes, reaching approximately 50° of scanning. The multibeam features of this lens are also numerically validated.
{"title":"Multibeam Antennas Based on 3-D Discrete Lenses With Magnified Field-of-View","authors":"Lisa Berretti;Renaud Loison;Esteban Menargues;Lucas Polo-López;Giovanni Toso;María García-Vigueras","doi":"10.1109/OJAP.2024.3469271","DOIUrl":"https://doi.org/10.1109/OJAP.2024.3469271","url":null,"abstract":"A new type of beamforming network (BFN) based on three-dimensional (3D) discrete lenses is introduced and numerically analyzed in this paper as an antenna system capable of generating multiple beams within a large Field-of-View (FoV). To enhance scanning capabilities, these lenses have their back part and associated feed array magnified relative to the front part. It is also shown that the radiating elements constituting the front part of the lens, due to the shape of their element factor, tend to limit the pointing direction of the overall antenna pattern, but their influence decreases as the lens dimension. Accordingly, a large front array is chosen to scan wide angles and mitigate this limitation. For the preliminary dimensioning and design of the entire BFN, a Geometrical Optics (GO) technique is employed. Subsequently, a rigorous methodology exploiting boundary conditions in the planes of symmetry is implemented to simulate the full-wave behavior of the front array of the lens, which is challenging due to limited computational resources for large arrays. This methodology, which also exploits the even/odd concept, is validated using a small array as a test case. By employing both the GO technique and rigorous full-wave analysis, it is numerically verified that this type of lens system can produce beams pointing up to 70° from the boresight direction while maintaining good levels of cross-polar discrimination in all azimuthal planes. Additionally, numerical evidence shows that these magnified lenses can increase their FoV compared to lenses with equal back and front sizes, reaching approximately 50° of scanning. The multibeam features of this lens are also numerically validated.","PeriodicalId":34267,"journal":{"name":"IEEE Open Journal of Antennas and Propagation","volume":"6 1","pages":"98-109"},"PeriodicalIF":3.5,"publicationDate":"2024-09-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10697111","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143107002","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}
Quantitative microwave imaging (MWI) involves solving the inverse scattering problem (ISP), which is characterized by nonlinearity and ill-posedness. To address the challenges posed by ISP, iterative linearization techniques have been introduced alongside regularization procedures. Born Iterative Method (BIM) and Distorted Born Iterative Method (DBIM) are well-established approaches in the field of microwave imaging. The primary objective of our study was to conduct a comparative analysis to evaluate the performance of traditional regularization techniques such as Truncated Singular Value Decomposition (TSVD), Tikhonov regularization, and the truncated Landweber algorithm with choosing different regularization parameters, within the framework of these established methods. The lack of explicit mention of optimal parameter values and comparison of regularization methods highlights a gap in the existing literature. Investigating and comparing different regularization methods and their corresponding optimal parameter values for different structures and features within the framework of linearization methods can provide valuable insights into effectively solving inverse problems in MWI. Additionally, exploring how different regularization parameters impact the accuracy and stability of the solutions obtained through BIM and DBIM can help researchers and practitioners make informed decisions to choose a regularization method and its corresponding parameter value for a specific problem. Our research aimed to provide a comprehensive baseline that would be beneficial for future studies and practical applications in microwave imaging.
{"title":"Performance Analysis of Iterative Methods in Microwave Imaging With Various Regularization Techniques","authors":"Reihaneh Ahmadi Vanhari;Ahmad Bakhtafrouz;Sima Noghanian","doi":"10.1109/OJAP.2024.3468334","DOIUrl":"https://doi.org/10.1109/OJAP.2024.3468334","url":null,"abstract":"Quantitative microwave imaging (MWI) involves solving the inverse scattering problem (ISP), which is characterized by nonlinearity and ill-posedness. To address the challenges posed by ISP, iterative linearization techniques have been introduced alongside regularization procedures. Born Iterative Method (BIM) and Distorted Born Iterative Method (DBIM) are well-established approaches in the field of microwave imaging. The primary objective of our study was to conduct a comparative analysis to evaluate the performance of traditional regularization techniques such as Truncated Singular Value Decomposition (TSVD), Tikhonov regularization, and the truncated Landweber algorithm with choosing different regularization parameters, within the framework of these established methods. The lack of explicit mention of optimal parameter values and comparison of regularization methods highlights a gap in the existing literature. Investigating and comparing different regularization methods and their corresponding optimal parameter values for different structures and features within the framework of linearization methods can provide valuable insights into effectively solving inverse problems in MWI. Additionally, exploring how different regularization parameters impact the accuracy and stability of the solutions obtained through BIM and DBIM can help researchers and practitioners make informed decisions to choose a regularization method and its corresponding parameter value for a specific problem. Our research aimed to provide a comprehensive baseline that would be beneficial for future studies and practical applications in microwave imaging.","PeriodicalId":34267,"journal":{"name":"IEEE Open Journal of Antennas and Propagation","volume":"5 6","pages":"1523-1538"},"PeriodicalIF":3.5,"publicationDate":"2024-09-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10695748","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142679244","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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