Pub Date : 2009-06-01DOI: 10.1109/APS.2009.5171731
O. Ergul, L. Gurel
We present the solution of extremely large electromagnetics problems formulated with surface integral equations (SIEs) and discretized with hundreds of millions of unknowns. Scattering and radiation problems involving three-dimensional closed metallic objects are formulated rigorously by using the combined-field integral equation (CFIE). Surfaces are discretized with small triangles, on which the Rao-Wilton-Glisson (RWG) functions are defined to expand the induced electric current and to test the boundary conditions for the tangential electric and magnetic fields. Discretizations of large objects with dimensions of hundreds of wavelengths lead to dense matrix equations with hundreds of millions of unknowns. Solutions are performed iteratively, where the matrix-vector multiplications are performed efficiently by using the multilevel fast multipole algorithm (MLFMA) [1]. Solutions are also parallelized on a cluster of computers using a hierarchical partitioning strategy [2], which is well suited for the multilevel structure of MLFMA. Accuracy and efficiency of the implementation are demonstrated on electromagnetic problems involving as many as 205 million unknowns, which are the largest integral-equation problems ever solved in the literature.
{"title":"Solutions of electromagnetics problems involving hundreds of millions of unknowns with parallel multilevel fast multipole algorithm","authors":"O. Ergul, L. Gurel","doi":"10.1109/APS.2009.5171731","DOIUrl":"https://doi.org/10.1109/APS.2009.5171731","url":null,"abstract":"We present the solution of extremely large electromagnetics problems formulated with surface integral equations (SIEs) and discretized with hundreds of millions of unknowns. Scattering and radiation problems involving three-dimensional closed metallic objects are formulated rigorously by using the combined-field integral equation (CFIE). Surfaces are discretized with small triangles, on which the Rao-Wilton-Glisson (RWG) functions are defined to expand the induced electric current and to test the boundary conditions for the tangential electric and magnetic fields. Discretizations of large objects with dimensions of hundreds of wavelengths lead to dense matrix equations with hundreds of millions of unknowns. Solutions are performed iteratively, where the matrix-vector multiplications are performed efficiently by using the multilevel fast multipole algorithm (MLFMA) [1]. Solutions are also parallelized on a cluster of computers using a hierarchical partitioning strategy [2], which is well suited for the multilevel structure of MLFMA. Accuracy and efficiency of the implementation are demonstrated on electromagnetic problems involving as many as 205 million unknowns, which are the largest integral-equation problems ever solved in the literature.","PeriodicalId":213759,"journal":{"name":"2009 IEEE Antennas and Propagation Society International Symposium","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131159535","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 : 2009-06-01DOI: 10.1109/APS.2009.5171953
H. Huang, Ken-Huang Lin, H. Su, Chin-Yih Wu, Hung-Hsuan Lin
We find that using metamaterial antenna radome made by 90 degree rotational symmetric unit cell structure can enhance the gain of dual-polarized antenna. The Jerusalem cross structure is proposed for dual-polarized antenna radome and its refraction index is designed to be near zero. This radome is designed for the WiMAX applications. Simulation results show that this antenna radome can improve the gain of dual-polarized patch antenna.
{"title":"Design of dual-polarized high-gain antenna radome by using Jerusalem cross metamaterial structure","authors":"H. Huang, Ken-Huang Lin, H. Su, Chin-Yih Wu, Hung-Hsuan Lin","doi":"10.1109/APS.2009.5171953","DOIUrl":"https://doi.org/10.1109/APS.2009.5171953","url":null,"abstract":"We find that using metamaterial antenna radome made by 90 degree rotational symmetric unit cell structure can enhance the gain of dual-polarized antenna. The Jerusalem cross structure is proposed for dual-polarized antenna radome and its refraction index is designed to be near zero. This radome is designed for the WiMAX applications. Simulation results show that this antenna radome can improve the gain of dual-polarized patch antenna.","PeriodicalId":213759,"journal":{"name":"2009 IEEE Antennas and Propagation Society International Symposium","volume":"53 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131224109","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 : 2009-06-01DOI: 10.1109/APS.2009.5171741
Chanam Lee, C. S. Lee
With the proposed scheme, the size of a microstrip antenna can be reduced as much as desired. However the antenna efficiency as well as the bandwidth will be lowered because of the reduced aperture area, which will be communicated further in the future.
{"title":"Electrically small microstrip antenna with height discontinuity","authors":"Chanam Lee, C. S. Lee","doi":"10.1109/APS.2009.5171741","DOIUrl":"https://doi.org/10.1109/APS.2009.5171741","url":null,"abstract":"With the proposed scheme, the size of a microstrip antenna can be reduced as much as desired. However the antenna efficiency as well as the bandwidth will be lowered because of the reduced aperture area, which will be communicated further in the future.","PeriodicalId":213759,"journal":{"name":"2009 IEEE Antennas and Propagation Society International Symposium","volume":"67 3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130953727","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 : 2009-06-01DOI: 10.1109/APS.2009.5171455
M. Joler, C. Christodoulou
We report on the initial stage of the development of a SRA system, whereas the complete system is meant to incorporate real-time computing, decision making, parameter optimization, and autonomous operation. When complete, the system could have a significant impact on smart communication systems in terms of their versatility and robustness of operation.
{"title":"On the development of a self-recoverable antenna system","authors":"M. Joler, C. Christodoulou","doi":"10.1109/APS.2009.5171455","DOIUrl":"https://doi.org/10.1109/APS.2009.5171455","url":null,"abstract":"We report on the initial stage of the development of a SRA system, whereas the complete system is meant to incorporate real-time computing, decision making, parameter optimization, and autonomous operation. When complete, the system could have a significant impact on smart communication systems in terms of their versatility and robustness of operation.","PeriodicalId":213759,"journal":{"name":"2009 IEEE Antennas and Propagation Society International Symposium","volume":"28 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132850113","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 : 2009-06-01DOI: 10.1109/APS.2009.5171798
D. Sullivan, J. Nadobny
Magnetic resonance imaging, or MRI, is a valuable diagnostic tool in modern medicine [1]. Among the key elements of the MRI instrumentation are highly resonant LC radio frequency (RF) coils, which consist of conducting wires and capacitors, as shown in Fig. 1. The coils are used as either stand alone surface coils, or they can be coupled together in a resonant configuration known as a “bird cage.” The loop inductance is provided by the wires and depends on the geometry of the loop as well as the cross-section of the wire. This paper describes the use of the finite-difference time-domain (FDTD) method [2] in simulating the RF coils. In particular, we evaluate the ability of the method to correctly determine the inductance provided by the wire.
{"title":"FDTD simulation of RF coils for MRI","authors":"D. Sullivan, J. Nadobny","doi":"10.1109/APS.2009.5171798","DOIUrl":"https://doi.org/10.1109/APS.2009.5171798","url":null,"abstract":"Magnetic resonance imaging, or MRI, is a valuable diagnostic tool in modern medicine [1]. Among the key elements of the MRI instrumentation are highly resonant LC radio frequency (RF) coils, which consist of conducting wires and capacitors, as shown in Fig. 1. The coils are used as either stand alone surface coils, or they can be coupled together in a resonant configuration known as a “bird cage.” The loop inductance is provided by the wires and depends on the geometry of the loop as well as the cross-section of the wire. This paper describes the use of the finite-difference time-domain (FDTD) method [2] in simulating the RF coils. In particular, we evaluate the ability of the method to correctly determine the inductance provided by the wire.","PeriodicalId":213759,"journal":{"name":"2009 IEEE Antennas and Propagation Society International Symposium","volume":"31 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133047795","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 : 2009-06-01DOI: 10.1109/APS.2009.5172273
Zikri Bayraktar, M. Gregory, D. Kern, D. Werner
The advantages and disadvantages of dielectric loading applied to electromagnetic devices such as antennas using high permittivity materials is well known. Sometimes overlooked, however, is the same effect using a material with magnetic properties. This is mainly due to the fact that most natural magnetic materials exhibit large losses that make them virtually unusable at high frequencies. If materials that exhibit magnetic and dielectric properties with reasonable losses were available then more advanced RF devices and antenna systems could be created. For instance, the use of these materials in conjunction with antennas would facilitate the development of designs with much smaller physical footprints than are typically possible, with few performance compromises [1]. Recently, composite magneto-dielectric substitutes, called metaferrites [2], have been engineered as a possible way to address this need for magnetic materials that are usable beyond 1 GHz. In [2], Kern et al. demonstrated that the properties of a PEC backed slab of magnetic material with frequency dependent permeability could effectively be achieved using a high impedance electromagnetic bandgap (EBG) structure. It was also shown that the real and imaginary parts of the effective permeability of an equivalent magnetic material slab could be related to the values of the surface impedance for the EBG structure. In this paper a new design technique for creating matched magnetodielectric metamaterial slabs is introduced. The technique is based on using a genetic algorithm (GA) to optimize [3,4] thin metallo-dielectric metasurfaces comprised of a periodic array of electrically small unit cells and backed by a perfectly conducting ground plane. Examples will be presented to demonstrate the effectiveness of this technique.
{"title":"Matched impedance thin composite magneto-dielectric metasurfaces","authors":"Zikri Bayraktar, M. Gregory, D. Kern, D. Werner","doi":"10.1109/APS.2009.5172273","DOIUrl":"https://doi.org/10.1109/APS.2009.5172273","url":null,"abstract":"The advantages and disadvantages of dielectric loading applied to electromagnetic devices such as antennas using high permittivity materials is well known. Sometimes overlooked, however, is the same effect using a material with magnetic properties. This is mainly due to the fact that most natural magnetic materials exhibit large losses that make them virtually unusable at high frequencies. If materials that exhibit magnetic and dielectric properties with reasonable losses were available then more advanced RF devices and antenna systems could be created. For instance, the use of these materials in conjunction with antennas would facilitate the development of designs with much smaller physical footprints than are typically possible, with few performance compromises [1]. Recently, composite magneto-dielectric substitutes, called metaferrites [2], have been engineered as a possible way to address this need for magnetic materials that are usable beyond 1 GHz. In [2], Kern et al. demonstrated that the properties of a PEC backed slab of magnetic material with frequency dependent permeability could effectively be achieved using a high impedance electromagnetic bandgap (EBG) structure. It was also shown that the real and imaginary parts of the effective permeability of an equivalent magnetic material slab could be related to the values of the surface impedance for the EBG structure. In this paper a new design technique for creating matched magnetodielectric metamaterial slabs is introduced. The technique is based on using a genetic algorithm (GA) to optimize [3,4] thin metallo-dielectric metasurfaces comprised of a periodic array of electrically small unit cells and backed by a perfectly conducting ground plane. Examples will be presented to demonstrate the effectiveness of this technique.","PeriodicalId":213759,"journal":{"name":"2009 IEEE Antennas and Propagation Society International Symposium","volume":"250 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133396716","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 : 2009-06-01DOI: 10.1109/APS.2009.5171685
R. Ferrayé, P. Dubois, I. Aliferis, J. Dauvignac, C. Pichot, C. Dedeban, J. Zolésio
A shape-gradient optimization based on contour deformations by means of Level Set method is used for reconstructing 2-D and 3-D perfectly conducting objects electromagnetic imaging. A frequency hopping technique is applied during the inverse scattering procedure for first locating the objects and reconstruct them roughly, then with higher frequencies to allow finer details to be retrieved. The numerical results clearly show that the inversion algorithm yields to accurate reconstruction of one or several objects even with noise-contaminated data and limited coverage of the incident fields.
{"title":"Shape-gradient optimization applied to the reconstruction of 2-D and 3-D metallic objects","authors":"R. Ferrayé, P. Dubois, I. Aliferis, J. Dauvignac, C. Pichot, C. Dedeban, J. Zolésio","doi":"10.1109/APS.2009.5171685","DOIUrl":"https://doi.org/10.1109/APS.2009.5171685","url":null,"abstract":"A shape-gradient optimization based on contour deformations by means of Level Set method is used for reconstructing 2-D and 3-D perfectly conducting objects electromagnetic imaging. A frequency hopping technique is applied during the inverse scattering procedure for first locating the objects and reconstruct them roughly, then with higher frequencies to allow finer details to be retrieved. The numerical results clearly show that the inversion algorithm yields to accurate reconstruction of one or several objects even with noise-contaminated data and limited coverage of the incident fields.","PeriodicalId":213759,"journal":{"name":"2009 IEEE Antennas and Propagation Society International Symposium","volume":"140 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133276579","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 : 2009-06-01DOI: 10.1109/APS.2009.5171699
Jason A. Ashbach, D. Kwon, P. Werner, D. Werner
We have proposed to make use of the low-loss characteristic of chalcogenide glass material for infrared filter applications. A stop-band chalcogenide filter design based on a grating structure was presented. The study shows that by varying the grating's geometric structure, the bandwidth can be adjusted and the resonant frequency can be fine-tuned. However, high-Q characteristics can only be realized with thicker grating structures. This initial investigation indicates that a chalcogenide glass stop-band filter can achieve reflectances higher than 90% at infrared wavelengths.
{"title":"Low-loss high-Q optical bandstop filter based on chalcogenide glass grating structures","authors":"Jason A. Ashbach, D. Kwon, P. Werner, D. Werner","doi":"10.1109/APS.2009.5171699","DOIUrl":"https://doi.org/10.1109/APS.2009.5171699","url":null,"abstract":"We have proposed to make use of the low-loss characteristic of chalcogenide glass material for infrared filter applications. A stop-band chalcogenide filter design based on a grating structure was presented. The study shows that by varying the grating's geometric structure, the bandwidth can be adjusted and the resonant frequency can be fine-tuned. However, high-Q characteristics can only be realized with thicker grating structures. This initial investigation indicates that a chalcogenide glass stop-band filter can achieve reflectances higher than 90% at infrared wavelengths.","PeriodicalId":213759,"journal":{"name":"2009 IEEE Antennas and Propagation Society International Symposium","volume":"20 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133298671","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 : 2009-06-01DOI: 10.1109/APS.2009.5172037
Shih-Yuan Chen, R. Ouedraogo, A. Temme, A. Diaz, E. Rothwell
In this paper, the impedance characteristic of the electrically small loop antenna has been significantly amended by introducing a layer of MNG MTM, which is formed by BC-SRRs. The 2-GHz prototype antenna has exhibited a peak gain of 5.7 dBi and efficiency of 87.8% verifying the effectiveness of the proposed SRR-based matching layer. This matching layer can, of course, be constructed using any other MNG MTM unit cells as long as they are properly aligned with the near-field magnetic field of the small loop.
{"title":"MNG-metamaterial-based efficient small loop antenna","authors":"Shih-Yuan Chen, R. Ouedraogo, A. Temme, A. Diaz, E. Rothwell","doi":"10.1109/APS.2009.5172037","DOIUrl":"https://doi.org/10.1109/APS.2009.5172037","url":null,"abstract":"In this paper, the impedance characteristic of the electrically small loop antenna has been significantly amended by introducing a layer of MNG MTM, which is formed by BC-SRRs. The 2-GHz prototype antenna has exhibited a peak gain of 5.7 dBi and efficiency of 87.8% verifying the effectiveness of the proposed SRR-based matching layer. This matching layer can, of course, be constructed using any other MNG MTM unit cells as long as they are properly aligned with the near-field magnetic field of the small loop.","PeriodicalId":213759,"journal":{"name":"2009 IEEE Antennas and Propagation Society International Symposium","volume":"2 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133318887","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 : 2009-06-01DOI: 10.1109/APS.2009.5172267
A. Eroglu
The design, simulation and implementation of low frequency electromagnetic devices on planar structures are given. Planar devices and components are designed and built on a ceramic-based material that allowed a surface-mount (SMT) application. Method of moment based electromagnetic field solvers are used to verify the design of the devices. Planar devices and components are then implemented and tested. Simulation results and experimental results are found to be very close. Results of this work can be used to design devices that operate at low frequency ranges for electromagnetic applications including industrial and military applications.
{"title":"Low frequency electromagnetic devices","authors":"A. Eroglu","doi":"10.1109/APS.2009.5172267","DOIUrl":"https://doi.org/10.1109/APS.2009.5172267","url":null,"abstract":"The design, simulation and implementation of low frequency electromagnetic devices on planar structures are given. Planar devices and components are designed and built on a ceramic-based material that allowed a surface-mount (SMT) application. Method of moment based electromagnetic field solvers are used to verify the design of the devices. Planar devices and components are then implemented and tested. Simulation results and experimental results are found to be very close. Results of this work can be used to design devices that operate at low frequency ranges for electromagnetic applications including industrial and military applications.","PeriodicalId":213759,"journal":{"name":"2009 IEEE Antennas and Propagation Society International Symposium","volume":"710 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2009-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133432779","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}
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