Pub Date : 2007-11-21DOI: 10.1109/ICEAA.2007.4387363
R. Maaskant, R. Mittra, A. Tijhuis
This paper describes a novel technique for generating the characteristic basis functions (CBFs) used to represent the surface currents on finite arrays of electrically interconnected antenna elements. The CBFs are high-level basis functions, defined on subdomains in which the original problem is divided. They are initially generated on extended subdomains; next, an easy-to-implement windowing technique is applied to them to truncate the undesired singularities in the currents generated at the artificial edges of the subdomains. The envelope of the window is trapezoidal in shape and we deliberately introduce a certain amount of overlap between the supports of the CBFs to ensure the continuity of the currents across the common interface between the adjacent subdomains. The accuracy and effectiveness of this method is demonstrated for a moderate as well as a large size array of tapered slot antennas (TSAs).
{"title":"Application of Trapezoidal-Shaped Characteristic Basis Functions to Arrays of Electrically Interconnected Antenna Elements","authors":"R. Maaskant, R. Mittra, A. Tijhuis","doi":"10.1109/ICEAA.2007.4387363","DOIUrl":"https://doi.org/10.1109/ICEAA.2007.4387363","url":null,"abstract":"This paper describes a novel technique for generating the characteristic basis functions (CBFs) used to represent the surface currents on finite arrays of electrically interconnected antenna elements. The CBFs are high-level basis functions, defined on subdomains in which the original problem is divided. They are initially generated on extended subdomains; next, an easy-to-implement windowing technique is applied to them to truncate the undesired singularities in the currents generated at the artificial edges of the subdomains. The envelope of the window is trapezoidal in shape and we deliberately introduce a certain amount of overlap between the supports of the CBFs to ensure the continuity of the currents across the common interface between the adjacent subdomains. The accuracy and effectiveness of this method is demonstrated for a moderate as well as a large size array of tapered slot antennas (TSAs).","PeriodicalId":273595,"journal":{"name":"2007 International Conference on Electromagnetics in Advanced Applications","volume":"6 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116889515","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 : 2007-11-21DOI: 10.1109/ICEAA.2007.4387371
A. Imre, L. Ji, G. Csaba, A. Orlov, G. Bernstein, W. Porod
We report the fabrication of, and demonstrate logic functionality in, networks of magnetically-coupled, nanometer-scale magnets performing binary computation in a magnetic quantum-dot cellular automata (MQCA) system. MQCA is an all-magnetic logic that offers low power dissipation and high integration density of functional elements.
{"title":"Magnetic Logic based on Field-Coupled Nanomagnets","authors":"A. Imre, L. Ji, G. Csaba, A. Orlov, G. Bernstein, W. Porod","doi":"10.1109/ICEAA.2007.4387371","DOIUrl":"https://doi.org/10.1109/ICEAA.2007.4387371","url":null,"abstract":"We report the fabrication of, and demonstrate logic functionality in, networks of magnetically-coupled, nanometer-scale magnets performing binary computation in a magnetic quantum-dot cellular automata (MQCA) system. MQCA is an all-magnetic logic that offers low power dissipation and high integration density of functional elements.","PeriodicalId":273595,"journal":{"name":"2007 International Conference on Electromagnetics in Advanced Applications","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131534773","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 : 2007-11-21DOI: 10.1109/ICEAA.2007.4387307
Y. Shkvarko
We address a new approach to solving radar imaging problems stated and treated as uncertain ill-conditioned inverse problems of nonparametric spatial power spectrum estimation via processing the finite number of independent observations of the degraded array data signals (one realization of the trajectory signal in the case of SAR). The idea is to adapt a statistically optimal minimum risk nonparametric power spectrum estimation approach to the radar imaging scenarios with model-level and system-level uncertainties. The proposed incorporation of the worst-case performance optimization-adapted robust regularization aggregated with the descriptive experiment design paradigm into the minimum risk nonparametric estimation strategy leads to a new unified doubly regularized minimum risk approach for robust adaptive high-resolution reconstructive imaging in the uncertain remote sensing scenarios.
{"title":"Unification of Descriptive Experiment Design and Worst-Case Performance Optimization-Adapted Regularization Paradigms for High-Resolution Reconstruction of Radar Imagery","authors":"Y. Shkvarko","doi":"10.1109/ICEAA.2007.4387307","DOIUrl":"https://doi.org/10.1109/ICEAA.2007.4387307","url":null,"abstract":"We address a new approach to solving radar imaging problems stated and treated as uncertain ill-conditioned inverse problems of nonparametric spatial power spectrum estimation via processing the finite number of independent observations of the degraded array data signals (one realization of the trajectory signal in the case of SAR). The idea is to adapt a statistically optimal minimum risk nonparametric power spectrum estimation approach to the radar imaging scenarios with model-level and system-level uncertainties. The proposed incorporation of the worst-case performance optimization-adapted robust regularization aggregated with the descriptive experiment design paradigm into the minimum risk nonparametric estimation strategy leads to a new unified doubly regularized minimum risk approach for robust adaptive high-resolution reconstructive imaging in the uncertain remote sensing scenarios.","PeriodicalId":273595,"journal":{"name":"2007 International Conference on Electromagnetics in Advanced Applications","volume":"24 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132363824","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 : 2007-11-21DOI: 10.1109/ICEAA.2007.4387398
V.M. Babicli
Let an incident wave propagates in a medium with wave-speed c1 and illuminates a convex interface to a medium with propagation speed c2, c2 > c1 . Let at some point O an incident ray meets an interface under critical reflection angle, then such a point looks like a source of an interference head wave which propagates in the first medium along the interface with the speed c2. The wave field in a vicinity of O is rather complicated. In the paper, we discuss its high-frequency asymptotics.
{"title":"On asymptotics of a wave field near the origin of an interference head wave","authors":"V.M. Babicli","doi":"10.1109/ICEAA.2007.4387398","DOIUrl":"https://doi.org/10.1109/ICEAA.2007.4387398","url":null,"abstract":"Let an incident wave propagates in a medium with wave-speed c<sub>1</sub> and illuminates a convex interface to a medium with propagation speed c<sub>2</sub>, c<sub>2</sub> > c<sub>1</sub> . Let at some point O an incident ray meets an interface under critical reflection angle, then such a point looks like a source of an interference head wave which propagates in the first medium along the interface with the speed c<sub>2</sub>. The wave field in a vicinity of O is rather complicated. In the paper, we discuss its high-frequency asymptotics.","PeriodicalId":273595,"journal":{"name":"2007 International Conference on Electromagnetics in Advanced Applications","volume":"47 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132460121","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 : 2007-11-21DOI: 10.1109/ICEAA.2007.4387225
M. Baldauf, J. Pontes, J. Timmermann, W. Wiesbeck
A mobile phone equipped with a multiple antenna system is investigated with respect to its human exposure to electromagnetic fields. The channel conditions and the demanded capacity determine the required exictation voltages, which are passed to a commercial software tool. To get rid of the influence of various antenna distances to the shaped human head a dielectric cuboid is considered as absorbing medium. Utilizing MIMO techniques with channel knowledge at the transmitter allows a reduction of the exposure by some 95%.
{"title":"Mobile MIMO Phones and Their Human Exposure to Electromagnetic Fields","authors":"M. Baldauf, J. Pontes, J. Timmermann, W. Wiesbeck","doi":"10.1109/ICEAA.2007.4387225","DOIUrl":"https://doi.org/10.1109/ICEAA.2007.4387225","url":null,"abstract":"A mobile phone equipped with a multiple antenna system is investigated with respect to its human exposure to electromagnetic fields. The channel conditions and the demanded capacity determine the required exictation voltages, which are passed to a commercial software tool. To get rid of the influence of various antenna distances to the shaped human head a dielectric cuboid is considered as absorbing medium. Utilizing MIMO techniques with channel knowledge at the transmitter allows a reduction of the exposure by some 95%.","PeriodicalId":273595,"journal":{"name":"2007 International Conference on Electromagnetics in Advanced Applications","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"131645389","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 : 2007-11-21DOI: 10.1109/ICEAA.2007.4387430
O. Tuncer, C. Lu, N. Nair, B. Shanker, L. Kempel
The generalized finite element method, first introduced by Babuska, is a framework that uses a partition of unity concept to construct a higher order representation of fields within a computation domain without using tessellation or imposing constraints on the space of basis functions. A key result is that the error representing the total field in the computational domain is related to the local representation error in each patch. This implies that one may be able to choose an appropriate set of basis in each sub-domain. While a bulk of literature based on this technique has been applied to construct solvers for scalar and elliptic differential equations, only recently was a method to analyze vector electromagnetic problems proposed. The basis functions proposed in the paper satisfy the requisite boundary conditions at the interface and demonstrate the appropriate h and p convergence. In this paper, the error in wave propagation is studied via a series of numerical experiments, for different classes of local basis functions-polynomials and exponentials.
{"title":"Analysis of Error Propagation in Vector Generalized Finite Element Methods","authors":"O. Tuncer, C. Lu, N. Nair, B. Shanker, L. Kempel","doi":"10.1109/ICEAA.2007.4387430","DOIUrl":"https://doi.org/10.1109/ICEAA.2007.4387430","url":null,"abstract":"The generalized finite element method, first introduced by Babuska, is a framework that uses a partition of unity concept to construct a higher order representation of fields within a computation domain without using tessellation or imposing constraints on the space of basis functions. A key result is that the error representing the total field in the computational domain is related to the local representation error in each patch. This implies that one may be able to choose an appropriate set of basis in each sub-domain. While a bulk of literature based on this technique has been applied to construct solvers for scalar and elliptic differential equations, only recently was a method to analyze vector electromagnetic problems proposed. The basis functions proposed in the paper satisfy the requisite boundary conditions at the interface and demonstrate the appropriate h and p convergence. In this paper, the error in wave propagation is studied via a series of numerical experiments, for different classes of local basis functions-polynomials and exponentials.","PeriodicalId":273595,"journal":{"name":"2007 International Conference on Electromagnetics in Advanced Applications","volume":"148 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132017613","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 : 2007-11-21DOI: 10.1109/ICEAA.2007.4387305
K. Fukunaga, S. Kurahashi
We measured the complex permittivities of various polymeric materials used as the insulation layers of PCBs from 1 MHz to 110 GHz using various measurement systems. The data obtained by different methods are in good agreement and the permittivities are almost constant at frequencies higher than 10 GHz. The experimental results reveal that the anisotropy in the complex permittivities of insulating materials for PCBs is large owing to the inhomogeneous internal structure. The experimental results also proved that the permittivity is strongly influenced by humidity. By introducing these experimental results, we encourage studies of high frequency characteristics in solid dielectrics and insulating materials in PCB industries.
{"title":"Dielectric Properties of Printed Circuit Board Insulations at Microwaves and Millimetre Waves","authors":"K. Fukunaga, S. Kurahashi","doi":"10.1109/ICEAA.2007.4387305","DOIUrl":"https://doi.org/10.1109/ICEAA.2007.4387305","url":null,"abstract":"We measured the complex permittivities of various polymeric materials used as the insulation layers of PCBs from 1 MHz to 110 GHz using various measurement systems. The data obtained by different methods are in good agreement and the permittivities are almost constant at frequencies higher than 10 GHz. The experimental results reveal that the anisotropy in the complex permittivities of insulating materials for PCBs is large owing to the inhomogeneous internal structure. The experimental results also proved that the permittivity is strongly influenced by humidity. By introducing these experimental results, we encourage studies of high frequency characteristics in solid dielectrics and insulating materials in PCB industries.","PeriodicalId":273595,"journal":{"name":"2007 International Conference on Electromagnetics in Advanced Applications","volume":"77 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133796800","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 : 2007-11-21DOI: 10.1109/ICEAA.2007.4387264
R. Villarino, G. Junkin, J. Parrón, J. M. González-Arbesú
Artificial magnetic surfaces have interesting applications in antenna design where one wants to replace, over a limited frequency range, electric conducting surfaces with magnetic equivalents. One of the many challenges in constructing such a surface is that of miniaturizing the resonator elements making up the structure whilst at the same time maintaining a reasonable bandwidth and a tolerable level of dielectric and copper losses. In this paper we present some novel structures, fabricated using chemical etching techniques, which have only 6.5% of the area of a capacitive loaded loop (CLL) and less than 30% of the area of spiral resonators and have measured return losses of less than 1.5 dB.
{"title":"Smaller resonators for artificial magnetic surfaces","authors":"R. Villarino, G. Junkin, J. Parrón, J. M. González-Arbesú","doi":"10.1109/ICEAA.2007.4387264","DOIUrl":"https://doi.org/10.1109/ICEAA.2007.4387264","url":null,"abstract":"Artificial magnetic surfaces have interesting applications in antenna design where one wants to replace, over a limited frequency range, electric conducting surfaces with magnetic equivalents. One of the many challenges in constructing such a surface is that of miniaturizing the resonator elements making up the structure whilst at the same time maintaining a reasonable bandwidth and a tolerable level of dielectric and copper losses. In this paper we present some novel structures, fabricated using chemical etching techniques, which have only 6.5% of the area of a capacitive loaded loop (CLL) and less than 30% of the area of spiral resonators and have measured return losses of less than 1.5 dB.","PeriodicalId":273595,"journal":{"name":"2007 International Conference on Electromagnetics in Advanced Applications","volume":"3 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123983746","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 : 2007-11-21DOI: 10.1109/ICEAA.2007.4387407
J.J.H. Wang, D. J. Triplett
This paper reports continued development of an ultra-broadband smart beam-steering circular array antenna with parasitically excited surface waveguides for low cost. The array has a low profile and is conformable to platforms, with a directivity of 5 to 10 dBi. Its steered beam and null cover full 360deg azimuth angles. Significant progress has been made in expanding the array's instantaneous bandwidth from 20-250 MHz to about 1000 MHz, which is an octaval bandwidth of 2:1 over the operating range of 1-2 GHz.
{"title":"Low-Profile Conformal Circular Beam-Steering Array with Ultra-Broad Instantaneous Bandwidth","authors":"J.J.H. Wang, D. J. Triplett","doi":"10.1109/ICEAA.2007.4387407","DOIUrl":"https://doi.org/10.1109/ICEAA.2007.4387407","url":null,"abstract":"This paper reports continued development of an ultra-broadband smart beam-steering circular array antenna with parasitically excited surface waveguides for low cost. The array has a low profile and is conformable to platforms, with a directivity of 5 to 10 dBi. Its steered beam and null cover full 360deg azimuth angles. Significant progress has been made in expanding the array's instantaneous bandwidth from 20-250 MHz to about 1000 MHz, which is an octaval bandwidth of 2:1 over the operating range of 1-2 GHz.","PeriodicalId":273595,"journal":{"name":"2007 International Conference on Electromagnetics in Advanced Applications","volume":"84 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121280303","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 : 2007-11-21DOI: 10.1109/ICEAA.2007.4387347
G. Granet, I. Fenniche, K. Edee, J. Plumey, E. Jehamy, M. Ney
This paper concerns a modal method for designing metal-plate lens structures. The method is based on coordinate transformation and the use of Maxwell's equations written under the covariant form. Furthermore the lens is considered as a medium with discontinuities described by Dirac Delta functions. We illustrate the method by showing the formation of the focus for various incident waves.
{"title":"New method for analysis of constrained metal plate lens","authors":"G. Granet, I. Fenniche, K. Edee, J. Plumey, E. Jehamy, M. Ney","doi":"10.1109/ICEAA.2007.4387347","DOIUrl":"https://doi.org/10.1109/ICEAA.2007.4387347","url":null,"abstract":"This paper concerns a modal method for designing metal-plate lens structures. The method is based on coordinate transformation and the use of Maxwell's equations written under the covariant form. Furthermore the lens is considered as a medium with discontinuities described by Dirac Delta functions. We illustrate the method by showing the formation of the focus for various incident waves.","PeriodicalId":273595,"journal":{"name":"2007 International Conference on Electromagnetics in Advanced Applications","volume":"12 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2007-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121369414","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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