Pub Date : 2010-12-03DOI: 10.1109/ICEAA.2010.5653856
C. Classen, B. Bandlow, R. Schuhmann
Whispering gallery modes of a flat dielectric disk are studied by means of analytical and numerical computational methods based on the finite integration technique. The results are compared to a high accuracy measurement. The frequently used semi-analytical method of effective refractive index has certain weaknesses in finding accurate eigenfrequencies and quality factors.
{"title":"Computational analysis of whispering gallery modes in flat dielectric disks","authors":"C. Classen, B. Bandlow, R. Schuhmann","doi":"10.1109/ICEAA.2010.5653856","DOIUrl":"https://doi.org/10.1109/ICEAA.2010.5653856","url":null,"abstract":"Whispering gallery modes of a flat dielectric disk are studied by means of analytical and numerical computational methods based on the finite integration technique. The results are compared to a high accuracy measurement. The frequently used semi-analytical method of effective refractive index has certain weaknesses in finding accurate eigenfrequencies and quality factors.","PeriodicalId":375707,"journal":{"name":"2010 International Conference on Electromagnetics in Advanced Applications","volume":"25 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":"114247011","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.2010.5653776
V. P. Bui, X. Wei, E. Li
This paper presents an advanced hybrid simulation technique to model the electromagnetic filed interactions between multi-transmitters and receivers in a complex closed environment; in which the method of moments/circuit method is used to accurately simulate the transceiver, and the longdistance electromagnetic field interaction is efficiently calculated by using the ray tracing technique based on the uniform theory of diffraction. The seamless combination between the circuit, numerical, and asymptotic approaches is the key to get accurate simulation results. Several numerical examples are presented to demonstrate the efficiency of the proposed hybrid technique.
{"title":"An efficient hybrid simulation technique for modeling the electromagnetic field propagation in a closed environment","authors":"V. P. Bui, X. Wei, E. Li","doi":"10.1109/ICEAA.2010.5653776","DOIUrl":"https://doi.org/10.1109/ICEAA.2010.5653776","url":null,"abstract":"This paper presents an advanced hybrid simulation technique to model the electromagnetic filed interactions between multi-transmitters and receivers in a complex closed environment; in which the method of moments/circuit method is used to accurately simulate the transceiver, and the longdistance electromagnetic field interaction is efficiently calculated by using the ray tracing technique based on the uniform theory of diffraction. The seamless combination between the circuit, numerical, and asymptotic approaches is the key to get accurate simulation results. Several numerical examples are presented to demonstrate the efficiency of the proposed hybrid technique.","PeriodicalId":375707,"journal":{"name":"2010 International Conference on Electromagnetics in Advanced Applications","volume":"9 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":"122725522","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.2010.5648879
R. Valkonen, S. Myllymaki, A. Huttunen, J. Holopainen, J. Ilvonen, P. Vainikainen, H. Jantunen
In this paper, compensation of the effect of the user's finger on the operation of a mobile terminal antenna is studied, using antenna selection as the compensation method. A dual-element antenna is compared with a single-element antenna occupying the same total antenna volume. The results show that antenna selection can provide an improvement of at least 2 dB in total efficiency at GSM1800 frequency band when the antenna is under influence of the index finger of the user.
{"title":"Compensation of finger effect on a mobile terminal antenna by antenna selection","authors":"R. Valkonen, S. Myllymaki, A. Huttunen, J. Holopainen, J. Ilvonen, P. Vainikainen, H. Jantunen","doi":"10.1109/ICEAA.2010.5648879","DOIUrl":"https://doi.org/10.1109/ICEAA.2010.5648879","url":null,"abstract":"In this paper, compensation of the effect of the user's finger on the operation of a mobile terminal antenna is studied, using antenna selection as the compensation method. A dual-element antenna is compared with a single-element antenna occupying the same total antenna volume. The results show that antenna selection can provide an improvement of at least 2 dB in total efficiency at GSM1800 frequency band when the antenna is under influence of the index finger of the user.","PeriodicalId":375707,"journal":{"name":"2010 International Conference on Electromagnetics in Advanced Applications","volume":"6 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":"123113001","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.2010.5652259
S. A. Mohsin, N. M. Sheikh
During magnetic resonance imaging (MRI), an implanted lead present in a patient's body scatters the radiofrquency (RF) field used for magnetic resonance. The resultant RF field can achieve very high values in the vicinity of the implant structure. The conduction currents flowing in tissue can cause dangerous resistive heating. Therefore scattering by implanted devices is an important safety issue in MR scanning. The scattering problem is large and computationally expensive. However the scattered field produced by the implant has a significant strength only in the vicinity of the implant and does not extend over a large tissue volume. Using this fact, a hybrid finite element-method of moments (FEM-MoM) formulation is used in this paper to compute the scattered fields of different implants.
{"title":"Scattering by implants during MRI: A simplified computational approach","authors":"S. A. Mohsin, N. M. Sheikh","doi":"10.1109/ICEAA.2010.5652259","DOIUrl":"https://doi.org/10.1109/ICEAA.2010.5652259","url":null,"abstract":"During magnetic resonance imaging (MRI), an implanted lead present in a patient's body scatters the radiofrquency (RF) field used for magnetic resonance. The resultant RF field can achieve very high values in the vicinity of the implant structure. The conduction currents flowing in tissue can cause dangerous resistive heating. Therefore scattering by implanted devices is an important safety issue in MR scanning. The scattering problem is large and computationally expensive. However the scattered field produced by the implant has a significant strength only in the vicinity of the implant and does not extend over a large tissue volume. Using this fact, a hybrid finite element-method of moments (FEM-MoM) formulation is used in this paper to compute the scattered fields of different implants.","PeriodicalId":375707,"journal":{"name":"2010 International Conference on Electromagnetics in Advanced Applications","volume":"21 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":"124031944","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.2010.5653742
P. Janpugdee, C. Wang, T. Chia
This paper presents a hybrid combination of the generalized ray expansion (GRE) method and high-frequency methods for analyzing the scattering and radiation problems incorporating electrically large and complex structures. A dense grid of ray tubes are launched from the phase centers of the subapertures making up the equivalent surface which encloses the target in the scattering problem, or the antenna in the radiation problem. Those rays represent the equivalent incident field on the target in the former case, and the field radiated by the antenna in the latter case. The rays are then traced through interactions with the target or the nearby structure based on high-frequency methods. The main advantage of the GRE method is that only one set of rays needs to be traced and it is independent of the excitation.
{"title":"Hybrid GRE-High frequency method for analysis of scattering and radiation problems incorporating large and complex structures","authors":"P. Janpugdee, C. Wang, T. Chia","doi":"10.1109/ICEAA.2010.5653742","DOIUrl":"https://doi.org/10.1109/ICEAA.2010.5653742","url":null,"abstract":"This paper presents a hybrid combination of the generalized ray expansion (GRE) method and high-frequency methods for analyzing the scattering and radiation problems incorporating electrically large and complex structures. A dense grid of ray tubes are launched from the phase centers of the subapertures making up the equivalent surface which encloses the target in the scattering problem, or the antenna in the radiation problem. Those rays represent the equivalent incident field on the target in the former case, and the field radiated by the antenna in the latter case. The rays are then traced through interactions with the target or the nearby structure based on high-frequency methods. The main advantage of the GRE method is that only one set of rays needs to be traced and it is independent of the excitation.","PeriodicalId":375707,"journal":{"name":"2010 International Conference on Electromagnetics in Advanced Applications","volume":"12 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":"129172311","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.2010.5653152
M. Yahya, Z. Awang
Cross polarization ratio (CPR) analysis can be used to determine the quality of circular polarization of an antenna as compared to the commonly used axial ratio (AR) analysis. The analysis is independent of E-field left and right polarity measurement which requires two circular polarized reference antennas of left and right. Through CPR, the quality of circular polarization of an antenna can be measured from a reference linear polarity antenna. A low complexity 2.4 GHz circular polarized truncated corner patch antenna is designed and fabricated on printed circuit board (PCB) to show the simple process to analyse circular polarization quality of the antenna. Simulation result is compared to the theoretical considerations and measurement of ratio and E-field results.
{"title":"Cross polarization ratio analysis of circular polarized patch antenna","authors":"M. Yahya, Z. Awang","doi":"10.1109/ICEAA.2010.5653152","DOIUrl":"https://doi.org/10.1109/ICEAA.2010.5653152","url":null,"abstract":"Cross polarization ratio (CPR) analysis can be used to determine the quality of circular polarization of an antenna as compared to the commonly used axial ratio (AR) analysis. The analysis is independent of E-field left and right polarity measurement which requires two circular polarized reference antennas of left and right. Through CPR, the quality of circular polarization of an antenna can be measured from a reference linear polarity antenna. A low complexity 2.4 GHz circular polarized truncated corner patch antenna is designed and fabricated on printed circuit board (PCB) to show the simple process to analyse circular polarization quality of the antenna. Simulation result is compared to the theoretical considerations and measurement of ratio and E-field results.","PeriodicalId":375707,"journal":{"name":"2010 International Conference on Electromagnetics in Advanced Applications","volume":"107 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":"114618701","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.2010.5653682
S. A. Mohsin, N. M. Sheikh, A. Maalik
The effect of skin tissue on the scattering of the MRI RF field by deep brain stimulation (DBS) leads is analyzed. RF induced heating occurs in the tissue surrounding the electrodes at the end of such a medical lead. The electric field and the induced temperature rise are found by solving the wave and heat equations. Spatial plots of the solutions are obtained. The presence of skin tissue also affects the transmission line behavior of the lead, and the resonant length; these effects are discussed.
{"title":"The effect of the MRI radiofrequency field on medical leads embedded beneath skin tissue","authors":"S. A. Mohsin, N. M. Sheikh, A. Maalik","doi":"10.1109/ICEAA.2010.5653682","DOIUrl":"https://doi.org/10.1109/ICEAA.2010.5653682","url":null,"abstract":"The effect of skin tissue on the scattering of the MRI RF field by deep brain stimulation (DBS) leads is analyzed. RF induced heating occurs in the tissue surrounding the electrodes at the end of such a medical lead. The electric field and the induced temperature rise are found by solving the wave and heat equations. Spatial plots of the solutions are obtained. The presence of skin tissue also affects the transmission line behavior of the lead, and the resonant length; these effects are discussed.","PeriodicalId":375707,"journal":{"name":"2010 International Conference on Electromagnetics in Advanced Applications","volume":"105 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":"127158965","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.2010.5651687
Prashanth Kumar, S. Altunc, C. Baum, C. Christodoulou, E. Schamiloglu
This paper describes the design and numerical simulations of a switch system to launch fast (100 ps), high-voltage (>100 kV) spherical TEM waves from the first focal point of a prolate-spheroidal impulse-radiating antenna.
{"title":"Launching a fast (100 ps) high-voltage (> 100 kV) pulse into a biological target","authors":"Prashanth Kumar, S. Altunc, C. Baum, C. Christodoulou, E. Schamiloglu","doi":"10.1109/ICEAA.2010.5651687","DOIUrl":"https://doi.org/10.1109/ICEAA.2010.5651687","url":null,"abstract":"This paper describes the design and numerical simulations of a switch system to launch fast (100 ps), high-voltage (>100 kV) spherical TEM waves from the first focal point of a prolate-spheroidal impulse-radiating antenna.","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":"127362168","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.2010.5654004
R. Graglia, A. Peterson
A new set of hierarchical vector basis functions that spans the curl-conforming reduced-gradient spaces of Nédélec on a triangular-prism cell is presented. These functions are constructed from orthogonal scalar polynomials to enhance their linear independence, which is a simpler process than an orthogonalization applied to the final vector functions. The new functions are compatible with those recently developed for tetrahedral and brick cells, in the sense that vector functions on a triangular face of a tetrahedron (or on a quadrilateral face of a brick) can easily be made continuous with analogous functions on the triangular (or quadrilateral) face of a prism cell. Specific functions are tabulated to order 3.5.
{"title":"Hierarchical vector polynomials for the triangular prism","authors":"R. Graglia, A. Peterson","doi":"10.1109/ICEAA.2010.5654004","DOIUrl":"https://doi.org/10.1109/ICEAA.2010.5654004","url":null,"abstract":"A new set of hierarchical vector basis functions that spans the curl-conforming reduced-gradient spaces of Nédélec on a triangular-prism cell is presented. These functions are constructed from orthogonal scalar polynomials to enhance their linear independence, which is a simpler process than an orthogonalization applied to the final vector functions. The new functions are compatible with those recently developed for tetrahedral and brick cells, in the sense that vector functions on a triangular face of a tetrahedron (or on a quadrilateral face of a brick) can easily be made continuous with analogous functions on the triangular (or quadrilateral) face of a prism cell. Specific functions are tabulated to order 3.5.","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":"127612864","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.2010.5651767
V. Daniele, Guido Lombardi
This paper provides a semi analytical procedure to factorize the two dimensional kernel involved in the quarter plane diffraction problem. The proposed method is based on the reduction of the factorization problem to the solution of a Fredholm integral equation of second kind. The solution of the Fredholm integral equation appears cumbersome since it involves two folded integrals. In order to reduce the number of the numerical unknowns a suitable representation of the W-H unknowns is proposed.
{"title":"On the solution of the double Wiener-Hopf equation involved in the quarter plane problem","authors":"V. Daniele, Guido Lombardi","doi":"10.1109/ICEAA.2010.5651767","DOIUrl":"https://doi.org/10.1109/ICEAA.2010.5651767","url":null,"abstract":"This paper provides a semi analytical procedure to factorize the two dimensional kernel involved in the quarter plane diffraction problem. The proposed method is based on the reduction of the factorization problem to the solution of a Fredholm integral equation of second kind. The solution of the Fredholm integral equation appears cumbersome since it involves two folded integrals. In order to reduce the number of the numerical unknowns a suitable representation of the W-H unknowns is proposed.","PeriodicalId":375707,"journal":{"name":"2010 International Conference on Electromagnetics in Advanced Applications","volume":"1 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":"126348301","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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