Pub Date : 2010-12-03DOI: 10.1109/ICEAA.2010.5653029
M. Bialkowski, A. R. Razali, Ashkan Boldaji, K. Cheng, P. Liu
This paper describes various miniaturization techniques of multiband antennas for portable transceivers. The considered techniques include folding, meandering and wrapping of the primary radiator. In addition, utilization of ground slots to widen the existing or generate new bands is described. These techniques are illustrated through design examples. Finally, a wideband antenna created by wrapping a quarter-elliptical monopole and a quarter-elliptical antenna with a complimentary slot are presented. These antennas cover all the popular wireless frequency bands in the 850MHz to 6GHz frequency spectrum with respect to the 6dB return loss reference. Full-wave EM simulations and experimental results for these compact multiband antennas are given.
{"title":"Miniaturization techniques of multiband antennas for portable transceivers","authors":"M. Bialkowski, A. R. Razali, Ashkan Boldaji, K. Cheng, P. Liu","doi":"10.1109/ICEAA.2010.5653029","DOIUrl":"https://doi.org/10.1109/ICEAA.2010.5653029","url":null,"abstract":"This paper describes various miniaturization techniques of multiband antennas for portable transceivers. The considered techniques include folding, meandering and wrapping of the primary radiator. In addition, utilization of ground slots to widen the existing or generate new bands is described. These techniques are illustrated through design examples. Finally, a wideband antenna created by wrapping a quarter-elliptical monopole and a quarter-elliptical antenna with a complimentary slot are presented. These antennas cover all the popular wireless frequency bands in the 850MHz to 6GHz frequency spectrum with respect to the 6dB return loss reference. Full-wave EM simulations and experimental results for these compact multiband antennas are given.","PeriodicalId":375707,"journal":{"name":"2010 International Conference on Electromagnetics in Advanced Applications","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133636921","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2010-12-03DOI: 10.1109/ICEAA.2010.5653108
J. Kot
The Nyström method is a higher-order numerical method for solving a wide range of integral equations. While “Locally Corrected” Nyström methods can be developed for general integral equations in electromagnetism, the simpler Nyström method itself cannot be easily applied, except in particular cases. Here we present a heuristic approach to the solution of a volume integral equation for dielectric scattering using a simple higher-order Nyström method, and demonstrate the basic operation of the method by calculating the radar cross-section of a dielectric cube.
{"title":"A higher-order Nyström method for dielectric scattering","authors":"J. Kot","doi":"10.1109/ICEAA.2010.5653108","DOIUrl":"https://doi.org/10.1109/ICEAA.2010.5653108","url":null,"abstract":"The Nyström method is a higher-order numerical method for solving a wide range of integral equations. While “Locally Corrected” Nyström methods can be developed for general integral equations in electromagnetism, the simpler Nyström method itself cannot be easily applied, except in particular cases. Here we present a heuristic approach to the solution of a volume integral equation for dielectric scattering using a simple higher-order Nyström method, and demonstrate the basic operation of the method by calculating the radar cross-section of a dielectric cube.","PeriodicalId":375707,"journal":{"name":"2010 International Conference on Electromagnetics in Advanced Applications","volume":"27 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133914568","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2010-12-03DOI: 10.1109/ICEAA.2010.5653874
J. Parker, M. Ferrara, J. Bracken, B. Himed
Traditional high-value monostatic imaging systems employ frequency-diverse pulses to form images from small synthetic apertures. In contrast, RF tomography utilizes a network of spatially diverse sensors to trade geometric diversity for bandwidth, permitting images to be formed with narrowband waveforms. Such a system could use inexpensive sensors with minimal ADC requirements, provide multiple viewpoints into urban canyons and other obscured environments, and offer graceful performance degradation under sensor attrition. However, numerous challenges must be overcome to field and operate such a system, including multistatic autofocus, precision timing requirements, and the development of appropriate image formation algorithms for large, sparsely populated synthetic apertures with anisotropic targets. AFRL has recently constructed an outdoor testing facility to explore these challenges with measured data. Preliminary experimental results are provided for this system, along with a description of remaining challenges and future research directions.
{"title":"Preliminary experimental results for RF tomography using distributed sensing","authors":"J. Parker, M. Ferrara, J. Bracken, B. Himed","doi":"10.1109/ICEAA.2010.5653874","DOIUrl":"https://doi.org/10.1109/ICEAA.2010.5653874","url":null,"abstract":"Traditional high-value monostatic imaging systems employ frequency-diverse pulses to form images from small synthetic apertures. In contrast, RF tomography utilizes a network of spatially diverse sensors to trade geometric diversity for bandwidth, permitting images to be formed with narrowband waveforms. Such a system could use inexpensive sensors with minimal ADC requirements, provide multiple viewpoints into urban canyons and other obscured environments, and offer graceful performance degradation under sensor attrition. However, numerous challenges must be overcome to field and operate such a system, including multistatic autofocus, precision timing requirements, and the development of appropriate image formation algorithms for large, sparsely populated synthetic apertures with anisotropic targets. AFRL has recently constructed an outdoor testing facility to explore these challenges with measured data. Preliminary experimental results are provided for this system, along with a description of remaining challenges and future research directions.","PeriodicalId":375707,"journal":{"name":"2010 International Conference on Electromagnetics in Advanced Applications","volume":"114 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131857175","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2010-12-03DOI: 10.1109/ICEAA.2010.5653873
J. Sautner, Nithya Jayapratha, V. Metlushko
Most of magnetic nano-structures today are ultrathin or nanostructured films and multilayers. The main challenge is to find a suitable technology to integrate and to contact nanostructures in a reliable manner. Here, we investigate the problem of contact integration into functional 3-D devices and evaluate the influence of 3-D magnetic layer geometry on performance of magneto-electronic devices. Real devices are truly 3-dimensional structures. Their topography must absolutely be taken into consideration during the design phase since their inherent non-planarity will profoundly affect their magnetization profile. Our initial results strongly indicate that the “non-flatness” of magnetic layer strongly influences the possible magnetic states, alters the switching mechanism and leads to totally new behavior, which was not observed in classic 2-D thin film magnetic structures.
{"title":"Functional 3-D magnetic nanostructures","authors":"J. Sautner, Nithya Jayapratha, V. Metlushko","doi":"10.1109/ICEAA.2010.5653873","DOIUrl":"https://doi.org/10.1109/ICEAA.2010.5653873","url":null,"abstract":"Most of magnetic nano-structures today are ultrathin or nanostructured films and multilayers. The main challenge is to find a suitable technology to integrate and to contact nanostructures in a reliable manner. Here, we investigate the problem of contact integration into functional 3-D devices and evaluate the influence of 3-D magnetic layer geometry on performance of magneto-electronic devices. Real devices are truly 3-dimensional structures. Their topography must absolutely be taken into consideration during the design phase since their inherent non-planarity will profoundly affect their magnetization profile. Our initial results strongly indicate that the “non-flatness” of magnetic layer strongly influences the possible magnetic states, alters the switching mechanism and leads to totally new behavior, which was not observed in classic 2-D thin film magnetic structures.","PeriodicalId":375707,"journal":{"name":"2010 International Conference on Electromagnetics in Advanced Applications","volume":"79 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131862364","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2010-12-03DOI: 10.1109/ICEAA.2010.5652957
C. Abeynayake, M. Ferguson
Metal detectors are widely used in landmine detection and other military applications. Knowledge of the depth, size and orientation of buried targets could contribute significantly to a reduction in the false alarm rate and improved efficiency in route clearance and other field applications. This paper explores a possible approach that could be used to determine target depth and target types using a metal detector with multiple receive coils of different configurations. The proposed approach has been practically implemented in an advanced dual receive coil metal detector array data set. Burial depths have been estimated for a range of targets buried from flush to 24 inches. This approach is shown to be robust to changes in target orientation and background soil conditions. This paper then explores a method which can be used to estimate depths without prior knowledge of the target type.
{"title":"Investigation on improved target detection capabilities using multi-channel, multiple receive coil metal detector data","authors":"C. Abeynayake, M. Ferguson","doi":"10.1109/ICEAA.2010.5652957","DOIUrl":"https://doi.org/10.1109/ICEAA.2010.5652957","url":null,"abstract":"Metal detectors are widely used in landmine detection and other military applications. Knowledge of the depth, size and orientation of buried targets could contribute significantly to a reduction in the false alarm rate and improved efficiency in route clearance and other field applications. This paper explores a possible approach that could be used to determine target depth and target types using a metal detector with multiple receive coils of different configurations. The proposed approach has been practically implemented in an advanced dual receive coil metal detector array data set. Burial depths have been estimated for a range of targets buried from flush to 24 inches. This approach is shown to be robust to changes in target orientation and background soil conditions. This paper then explores a method which can be used to estimate depths without prior knowledge of the target type.","PeriodicalId":375707,"journal":{"name":"2010 International Conference on Electromagnetics in Advanced Applications","volume":"8 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"134322285","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2010-12-03DOI: 10.1109/ICEAA.2010.5652240
H. G. Wang, H. Li, D. Liu, X. H. Yu
This paper provides a quasi-three dimensional version of Multi-Level Green's Function Interpolation Method for multilayered problems. In this method the cross level interfaction phase is used to enhance the interpolation efficiency for the multilayered problems with vias and patches. The numerical analysis shows the efficiency of this method.
{"title":"A quasi-three dimensional Multi-Level Green's Function Interpolation Method for multilayered structures","authors":"H. G. Wang, H. Li, D. Liu, X. H. Yu","doi":"10.1109/ICEAA.2010.5652240","DOIUrl":"https://doi.org/10.1109/ICEAA.2010.5652240","url":null,"abstract":"This paper provides a quasi-three dimensional version of Multi-Level Green's Function Interpolation Method for multilayered problems. In this method the cross level interfaction phase is used to enhance the interpolation efficiency for the multilayered problems with vias and patches. The numerical analysis shows the efficiency of this method.","PeriodicalId":375707,"journal":{"name":"2010 International Conference on Electromagnetics in Advanced Applications","volume":"32 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133543848","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2010-12-03DOI: 10.1109/ICEAA.2010.5651246
J. Shibayama, Y. Wakabayashi, J. Yamauchi, H. Nakano
This paper describes the application of an efficient implicit finite-difference time-domain method (FDTD) based on the locally one-dimensional (LOD) scheme to the analysis of periodic band-gap structures. In particular, the technique of oblique incidence is introduced into the periodic LOD-FDTD method. To maintain a tridiagonal system of linear equations, we newly develop a three-step algorithm consistent with the LOD procedure. In addition, the Sherman-Morrison formula is used to solve a cyclic matrix problem resulting from the application of the implicit scheme to the periodic boundary condition. The effectiveness of the present method is investigated through the analysis of periodic band-gap structures at oblique incidence. It is shown that the method efficiently provides the transmission spectrum, compared with the traditional explicit periodic FDTD method.
{"title":"Wideband analysis of periodic electromagnetic elements","authors":"J. Shibayama, Y. Wakabayashi, J. Yamauchi, H. Nakano","doi":"10.1109/ICEAA.2010.5651246","DOIUrl":"https://doi.org/10.1109/ICEAA.2010.5651246","url":null,"abstract":"This paper describes the application of an efficient implicit finite-difference time-domain method (FDTD) based on the locally one-dimensional (LOD) scheme to the analysis of periodic band-gap structures. In particular, the technique of oblique incidence is introduced into the periodic LOD-FDTD method. To maintain a tridiagonal system of linear equations, we newly develop a three-step algorithm consistent with the LOD procedure. In addition, the Sherman-Morrison formula is used to solve a cyclic matrix problem resulting from the application of the implicit scheme to the periodic boundary condition. The effectiveness of the present method is investigated through the analysis of periodic band-gap structures at oblique incidence. It is shown that the method efficiently provides the transmission spectrum, compared with the traditional explicit periodic FDTD method.","PeriodicalId":375707,"journal":{"name":"2010 International Conference on Electromagnetics in Advanced Applications","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117225559","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2010-12-03DOI: 10.1109/ICEAA.2010.5650958
S. Zhao, C. Fumeaux, C. Coleman
The size reduction for resonant monopoles is an important issue for HF and VHF antennas. Unfortunately, size reduction results in degradation in both efficiency and bandwidth, as is well known from the fundamental limits on small antennas [1]. This paper firstly introduces a MATLAB-controlled NEC2 simulation tool with genetic algorithm optimization, and uses this to find the optimal position of inductors for a shortened monopole with L-section matching networks. Trade-offs between bandwidth and efficiency are investigated and demonstrated in a systematic fashion for a single inductor case. Various multi-inductor loading schemes are also investigated; including central symmetrically distributed and arbitrarily distributed two-inductor loading schemes. The ultimate goal of the research is to find an optimal distribution of inductors on a reduced-size resonant monopole.
{"title":"Optimal positions of loading for a shortened resonant monopole using genetic algorithm","authors":"S. Zhao, C. Fumeaux, C. Coleman","doi":"10.1109/ICEAA.2010.5650958","DOIUrl":"https://doi.org/10.1109/ICEAA.2010.5650958","url":null,"abstract":"The size reduction for resonant monopoles is an important issue for HF and VHF antennas. Unfortunately, size reduction results in degradation in both efficiency and bandwidth, as is well known from the fundamental limits on small antennas [1]. This paper firstly introduces a MATLAB-controlled NEC2 simulation tool with genetic algorithm optimization, and uses this to find the optimal position of inductors for a shortened monopole with L-section matching networks. Trade-offs between bandwidth and efficiency are investigated and demonstrated in a systematic fashion for a single inductor case. Various multi-inductor loading schemes are also investigated; including central symmetrically distributed and arbitrarily distributed two-inductor loading schemes. The ultimate goal of the research is to find an optimal distribution of inductors on a reduced-size resonant monopole.","PeriodicalId":375707,"journal":{"name":"2010 International Conference on Electromagnetics in Advanced Applications","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116514127","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2010-12-03DOI: 10.1109/ICEAA.2010.5653120
J. Puskely, Z. Nováček
A novel minimization method based on the principle of Fourier iterative method combining a global optimization with a compression method is used. The method uses conventional amplitude measurements on two surfaces placed in different distances from the antenna aperture. The global Particle Swarm Optimization (PSO) is used to minimize the fitness function (functional) and the Discrete Cosine Transform (DCT) is considered to reduce the number of unknown variables. The proposed method was applied for the reconstruction of the antenna array radiation patterns from data measured on the cylindrical surfaces.
{"title":"Far-field reconstruction based on compression method from cylindrical near-field phaseless measurements","authors":"J. Puskely, Z. Nováček","doi":"10.1109/ICEAA.2010.5653120","DOIUrl":"https://doi.org/10.1109/ICEAA.2010.5653120","url":null,"abstract":"A novel minimization method based on the principle of Fourier iterative method combining a global optimization with a compression method is used. The method uses conventional amplitude measurements on two surfaces placed in different distances from the antenna aperture. The global Particle Swarm Optimization (PSO) is used to minimize the fitness function (functional) and the Discrete Cosine Transform (DCT) is considered to reduce the number of unknown variables. The proposed method was applied for the reconstruction of the antenna array radiation patterns from data measured on the cylindrical surfaces.","PeriodicalId":375707,"journal":{"name":"2010 International Conference on Electromagnetics in Advanced Applications","volume":"134 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115163948","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2010-12-03DOI: 10.1109/ICEAA.2010.5652281
Ming-lin Yang, X. Sheng
The finite element-boundary integral-multilevel fast multipole algorithm (FE-BI-MLFMA) has shown to be very general and powerful for 3D scattering. To efficiently model cavity targets, a concave FE-BI-MLFMA is presented in this paper, which can significantly reduce the dispersion error from the FEM and improve the efficiency of FE-BI-MLFMA especially for nonuniform cavities. To eliminate the problem of slow convergence caused by concave surface, an efficient preconditioner based on the sparse approximate inverse (SAI) is constructed in this paper. Numerical experiments demonstrate the accuracy and efficiency of this SAI-preconditioned concave FE-BI-MLFMA for nonuniform deep and large cavites. Furthermore, the FE-BI-MLFMA is parallelized and has successfully compute the scattering from a conducting sphere with 1000 -wavelength diameter using more than 400 million unknowns.
{"title":"Parallel FE-BI-MLFMA for scattering by extremely large targets with cavities","authors":"Ming-lin Yang, X. Sheng","doi":"10.1109/ICEAA.2010.5652281","DOIUrl":"https://doi.org/10.1109/ICEAA.2010.5652281","url":null,"abstract":"The finite element-boundary integral-multilevel fast multipole algorithm (FE-BI-MLFMA) has shown to be very general and powerful for 3D scattering. To efficiently model cavity targets, a concave FE-BI-MLFMA is presented in this paper, which can significantly reduce the dispersion error from the FEM and improve the efficiency of FE-BI-MLFMA especially for nonuniform cavities. To eliminate the problem of slow convergence caused by concave surface, an efficient preconditioner based on the sparse approximate inverse (SAI) is constructed in this paper. Numerical experiments demonstrate the accuracy and efficiency of this SAI-preconditioned concave FE-BI-MLFMA for nonuniform deep and large cavites. Furthermore, the FE-BI-MLFMA is parallelized and has successfully compute the scattering from a conducting sphere with 1000 -wavelength diameter using more than 400 million unknowns.","PeriodicalId":375707,"journal":{"name":"2010 International Conference on Electromagnetics in Advanced Applications","volume":"22 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2010-12-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"115198095","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
京公网安备 11010802042870号
京ICP备2023020795号-1
扫码关注我们
求助内容：
应助结果提醒方式：