IEEE Antennas and Propagation Society International Symposium. 2001 Digest. Held in conjunction with: USNC/URSI National Radio Science Meeting (Cat. No.01CH37229)最新文献
Electromagnetic wave scattering by two rectangular troughs on a conducting ground plane, which is the simplest trough-grating geometry, is rigorously analyzed using the Kobayashi potential method. The formulation is extended and derived here for the H polarization case. By using the derived far field solution, numerical calculations of scattering patterns have been done and the disparity between E and H polarizations has been also discussed. Here the time harmonic factor e/sup -i/spl omega/t/ is assumed and suppressed throughout the context.
{"title":"Electromagnetic wave scattering by two rectangular troughs on a ground plane - H polarization case","authors":"R. Sato, H. Shirai","doi":"10.1109/APS.2001.959572","DOIUrl":"https://doi.org/10.1109/APS.2001.959572","url":null,"abstract":"Electromagnetic wave scattering by two rectangular troughs on a conducting ground plane, which is the simplest trough-grating geometry, is rigorously analyzed using the Kobayashi potential method. The formulation is extended and derived here for the H polarization case. By using the derived far field solution, numerical calculations of scattering patterns have been done and the disparity between E and H polarizations has been also discussed. Here the time harmonic factor e/sup -i/spl omega/t/ is assumed and suppressed throughout the context.","PeriodicalId":159827,"journal":{"name":"IEEE Antennas and Propagation Society International Symposium. 2001 Digest. Held in conjunction with: USNC/URSI National Radio Science Meeting (Cat. No.01CH37229)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130603142","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}
In this paper, we present results from analysis of GPS signals received in Ankara, Turkey. The main purpose of this study is to introduce a new technique, which uses pseudorange differences instead of phase differences, that enables us to make rough estimates of the TEC by using GPS observables. In this algorithm, we use the time difference between pseudoranges of L1 and L2 signals to obtain hourly TEC value. The results for the coverage area of the system is presented.
{"title":"Ionospheric total electron content measurements by analyzing GPS data of Ankara, Turkey","authors":"C. B. Erol, P. Guven","doi":"10.1109/APS.2001.960049","DOIUrl":"https://doi.org/10.1109/APS.2001.960049","url":null,"abstract":"In this paper, we present results from analysis of GPS signals received in Ankara, Turkey. The main purpose of this study is to introduce a new technique, which uses pseudorange differences instead of phase differences, that enables us to make rough estimates of the TEC by using GPS observables. In this algorithm, we use the time difference between pseudoranges of L1 and L2 signals to obtain hourly TEC value. The results for the coverage area of the system is presented.","PeriodicalId":159827,"journal":{"name":"IEEE Antennas and Propagation Society International Symposium. 2001 Digest. Held in conjunction with: USNC/URSI National Radio Science Meeting (Cat. No.01CH37229)","volume":"50 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"130641352","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}
This paper presents the numerically simulated specific absorption rate (SAR) within the human head due to cellular telephones. The frequency considered was 825 MHz and the time averaged radiated power of 0.6 W was used. The influence of the geometrical change of nearby feed on SAR for the homogeneous head model was analyzed. The FDTD code was modified for a parallel processing machine and run on 8 CPU.
{"title":"FDTD calculation of SAR for the monopole antenna on the conducting box in terms of the structure near by feed","authors":"J. Byun, Juhyung Lee","doi":"10.1109/APS.2001.959625","DOIUrl":"https://doi.org/10.1109/APS.2001.959625","url":null,"abstract":"This paper presents the numerically simulated specific absorption rate (SAR) within the human head due to cellular telephones. The frequency considered was 825 MHz and the time averaged radiated power of 0.6 W was used. The influence of the geometrical change of nearby feed on SAR for the homogeneous head model was analyzed. The FDTD code was modified for a parallel processing machine and run on 8 CPU.","PeriodicalId":159827,"journal":{"name":"IEEE Antennas and Propagation Society International Symposium. 2001 Digest. Held in conjunction with: USNC/URSI National Radio Science Meeting (Cat. No.01CH37229)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123854528","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}
A microwave radiometer designed for remote sensing infers geophysical information from the thermal emission from natural targets. The most useful frequencies span 6 GHz to 37 GHz, and incorporate a scanning antenna to provide radiometric maps of the Earth surface and the atmospheric burden. This paper focuses on radiometric imaging systems, and the observational value offered by these systems since they were first flown on spacecraft nearly 30 years ago.
{"title":"Passive microwave imaging from spacecraft","authors":"C. Swift","doi":"10.1109/APS.2001.959536","DOIUrl":"https://doi.org/10.1109/APS.2001.959536","url":null,"abstract":"A microwave radiometer designed for remote sensing infers geophysical information from the thermal emission from natural targets. The most useful frequencies span 6 GHz to 37 GHz, and incorporate a scanning antenna to provide radiometric maps of the Earth surface and the atmospheric burden. This paper focuses on radiometric imaging systems, and the observational value offered by these systems since they were first flown on spacecraft nearly 30 years ago.","PeriodicalId":159827,"journal":{"name":"IEEE Antennas and Propagation Society International Symposium. 2001 Digest. Held in conjunction with: USNC/URSI National Radio Science Meeting (Cat. No.01CH37229)","volume":"43 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123953863","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}
The Green Bank Telescope (GBT) at the National Radio Astronomy Observatory (NRAO) site in Green Bank, WV, was completed in June 2000. At the time of writing, the GBT is undergoing testing of the various systems and characterization of the actual structural modes. It is the largest, fully-steerable radio telescope in the world. The main reflector which is a solid-surface paraboloid has an unblocked 100-meter projected aperture. The telescope will operate at prime focus from 25 MHz to 1200 MHz and at Gregorian focus from 1.15 GHz to /spl ges/ 100 GHz. It is a state-of-the-art instrument with an active surface to compensate for deformations of the primary reflector backup structure due to external loads. The GBT has a unique six-degree of freedom subreflector and a three-degree of freedom prime focus mount that allow realigning of the optics which is required as the telescope moves in elevation. A receiver turret that holds 8 secondary focus receivers will provide rapid frequency agility for the telescope. This paper describes the metrology system, based on laser rangefinders, that has been developed at NRAO for the realization of the active surface and precision pointing of the GBT.
{"title":"Measurement system for the Green Bank Telescope","authors":"D. H. Parker, S. Srikanth","doi":"10.1109/APS.2001.959534","DOIUrl":"https://doi.org/10.1109/APS.2001.959534","url":null,"abstract":"The Green Bank Telescope (GBT) at the National Radio Astronomy Observatory (NRAO) site in Green Bank, WV, was completed in June 2000. At the time of writing, the GBT is undergoing testing of the various systems and characterization of the actual structural modes. It is the largest, fully-steerable radio telescope in the world. The main reflector which is a solid-surface paraboloid has an unblocked 100-meter projected aperture. The telescope will operate at prime focus from 25 MHz to 1200 MHz and at Gregorian focus from 1.15 GHz to /spl ges/ 100 GHz. It is a state-of-the-art instrument with an active surface to compensate for deformations of the primary reflector backup structure due to external loads. The GBT has a unique six-degree of freedom subreflector and a three-degree of freedom prime focus mount that allow realigning of the optics which is required as the telescope moves in elevation. A receiver turret that holds 8 secondary focus receivers will provide rapid frequency agility for the telescope. This paper describes the metrology system, based on laser rangefinders, that has been developed at NRAO for the realization of the active surface and precision pointing of the GBT.","PeriodicalId":159827,"journal":{"name":"IEEE Antennas and Propagation Society International Symposium. 2001 Digest. Held in conjunction with: USNC/URSI National Radio Science Meeting (Cat. No.01CH37229)","volume":"72 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124018294","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}
The unique geometrical properties of fractals have been proven to be useful to design advanced antennas. Enhanced performance in terms of size, gain or multiband behaviour is observed in fractal-shaped antennas. Here, a small and high directivity antenna based on the Sierpinski bowtie geometry is presented.
{"title":"Bowtie microstrip patch antenna based on the Sierpinski fractal","authors":"J. Anguera, C. Puente, C. Borja, R. Montero","doi":"10.1109/APS.2001.960058","DOIUrl":"https://doi.org/10.1109/APS.2001.960058","url":null,"abstract":"The unique geometrical properties of fractals have been proven to be useful to design advanced antennas. Enhanced performance in terms of size, gain or multiband behaviour is observed in fractal-shaped antennas. Here, a small and high directivity antenna based on the Sierpinski bowtie geometry is presented.","PeriodicalId":159827,"journal":{"name":"IEEE Antennas and Propagation Society International Symposium. 2001 Digest. Held in conjunction with: USNC/URSI National Radio Science Meeting (Cat. No.01CH37229)","volume":"26 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124035786","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}
Radar imaging is traditionally performed by wideband radar systems to achieve high range resolution of objects. Unfortunately due to cost, frequency allocation, or physical limitations, most radars are unable to operate over a broad range of frequencies. We propose a methodology to achieve high range resolution by phase integration in the frequency domain of a narrowband radar signal. This process compares with the radio camera interferometry approach in that it uses a phased array to achieve spatial resolution and a ground penetration image formation process that spatially samples a region in two dimensions. Our approach unifies the previous approaches, and integrate return signals in the frequency domain which simplifies the registration of the return signal. We begin by describing the basic methodology of collecting data with a two dimensional antenna array using a narrowband linear FM signal. We then describe how each phase bin is converted to the frequency domain and integrated in time. Next, we discuss the Fourier transform followed by the pulse decompression process. Finally we discuss the sampling approach for the two dimensional synthetic aperture and show simulated results.
{"title":"Phase integration for two dimensional radar image formation","authors":"R. Bonneau","doi":"10.1109/APS.2001.958854","DOIUrl":"https://doi.org/10.1109/APS.2001.958854","url":null,"abstract":"Radar imaging is traditionally performed by wideband radar systems to achieve high range resolution of objects. Unfortunately due to cost, frequency allocation, or physical limitations, most radars are unable to operate over a broad range of frequencies. We propose a methodology to achieve high range resolution by phase integration in the frequency domain of a narrowband radar signal. This process compares with the radio camera interferometry approach in that it uses a phased array to achieve spatial resolution and a ground penetration image formation process that spatially samples a region in two dimensions. Our approach unifies the previous approaches, and integrate return signals in the frequency domain which simplifies the registration of the return signal. We begin by describing the basic methodology of collecting data with a two dimensional antenna array using a narrowband linear FM signal. We then describe how each phase bin is converted to the frequency domain and integrated in time. Next, we discuss the Fourier transform followed by the pulse decompression process. Finally we discuss the sampling approach for the two dimensional synthetic aperture and show simulated results.","PeriodicalId":159827,"journal":{"name":"IEEE Antennas and Propagation Society International Symposium. 2001 Digest. Held in conjunction with: USNC/URSI National Radio Science Meeting (Cat. No.01CH37229)","volume":"45 10","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120893369","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}
H. Anastassiu, A. Kostaridis, C. Biniaris, D. Kaklamani
Standard integral equation techniques, such as the moment method (MoM) face difficulties for very large antenna sizes, since the memory and CPU time they require may increase beyond computational limits. The method of auxiliary sources (MAS) demands substantially lower CPU time than MoM, retaining, nevertheless, the MoM accuracy. Unfortunately, its capabilities are depleted when applied to thin or open structures, due to the mandatory proximity of source and collocation points occurring in such geometries. The modified method of auxiliary sources (MMAS) has been developed to circumvent this difficulty, and has been successfully applied to the analysis of microstrip patch antennas, even when the dielectric substrate is thin enough to render conventional MAS inapplicable. In this paper, the MMAS is applied to the analysis of microstrip patch arrays, conformal to cylindrical surfaces, a model that simulates a communication antenna mounted to an aircraft fuselage. Several unpublished features of MMAS are discussed, whereas extensive, recently produced numerical results are presented and compared to reference solutions, validating the reliability and versatility of the method.
{"title":"Reduced complexity analysis of microstrip patch arrays, conformally mounted to a cylindrical conducting surface","authors":"H. Anastassiu, A. Kostaridis, C. Biniaris, D. Kaklamani","doi":"10.1109/APS.2001.959734","DOIUrl":"https://doi.org/10.1109/APS.2001.959734","url":null,"abstract":"Standard integral equation techniques, such as the moment method (MoM) face difficulties for very large antenna sizes, since the memory and CPU time they require may increase beyond computational limits. The method of auxiliary sources (MAS) demands substantially lower CPU time than MoM, retaining, nevertheless, the MoM accuracy. Unfortunately, its capabilities are depleted when applied to thin or open structures, due to the mandatory proximity of source and collocation points occurring in such geometries. The modified method of auxiliary sources (MMAS) has been developed to circumvent this difficulty, and has been successfully applied to the analysis of microstrip patch antennas, even when the dielectric substrate is thin enough to render conventional MAS inapplicable. In this paper, the MMAS is applied to the analysis of microstrip patch arrays, conformal to cylindrical surfaces, a model that simulates a communication antenna mounted to an aircraft fuselage. Several unpublished features of MMAS are discussed, whereas extensive, recently produced numerical results are presented and compared to reference solutions, validating the reliability and versatility of the method.","PeriodicalId":159827,"journal":{"name":"IEEE Antennas and Propagation Society International Symposium. 2001 Digest. Held in conjunction with: USNC/URSI National Radio Science Meeting (Cat. No.01CH37229)","volume":"5 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114192671","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}
This paper presents the development of 2.5D and 3D extensions of a 2D procedure that is described in an earlier paper (see Zhang, Z. et al., Electronics Letters, vol.36, no.5, p.464-5, 2000) for modeling propagation environments. These methods are based on dividing the propagation region into cells whereby the number of cells is decided by the number of vertices of structures instead of their dimensions. Results from the 2.5D and 3D methods show significant improvement in computational efficiency. Specifically, the CPU time for the 2.5D method is less than 5% of that of the visibility ray tracing method. Accuracy, on the other hand, is related to that of a traditional ray tracing method and includes accounting for reflected, transmitted and diffracted rays.
本文介绍了在早期论文中描述的2D程序的2.5D和3D扩展的发展(见Zhang, Z. et al.， Electronics Letters, vol.36, no. 6)。5, p.464-5, 2000)建模传播环境。这些方法是基于将传播区域划分为细胞，细胞的数量由结构的顶点数量而不是它们的尺寸决定。2.5D和3D方法的计算效率显著提高。具体来说，2.5D方法的CPU时间不到可见光光线追踪方法的5%。另一方面，准确度与传统的光线追踪方法有关，包括对反射、透射和衍射光线的计算。
{"title":"New computationally efficient 2.5D and 3D ray tracing algorithms for modeling propagation environments","authors":"Zhijun Zhang, Z. Yun, M. Iskander","doi":"10.1109/APS.2001.958891","DOIUrl":"https://doi.org/10.1109/APS.2001.958891","url":null,"abstract":"This paper presents the development of 2.5D and 3D extensions of a 2D procedure that is described in an earlier paper (see Zhang, Z. et al., Electronics Letters, vol.36, no.5, p.464-5, 2000) for modeling propagation environments. These methods are based on dividing the propagation region into cells whereby the number of cells is decided by the number of vertices of structures instead of their dimensions. Results from the 2.5D and 3D methods show significant improvement in computational efficiency. Specifically, the CPU time for the 2.5D method is less than 5% of that of the visibility ray tracing method. Accuracy, on the other hand, is related to that of a traditional ray tracing method and includes accounting for reflected, transmitted and diffracted rays.","PeriodicalId":159827,"journal":{"name":"IEEE Antennas and Propagation Society International Symposium. 2001 Digest. Held in conjunction with: USNC/URSI National Radio Science Meeting (Cat. No.01CH37229)","volume":"204 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116180982","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}
Field distributions of a curved dielectric waveguide with rectangular cross-section are investigated by a network method combined with a modified EDC approximation. It is shown that the field maximum tends to outwardly shift. Field profiles in the inner and outer space regions of the waveguide are also drawn. Results of numerical analysis show very good agreement with experimental results while the present approach is simpler and more convenient compared with those applying the WKB method.
{"title":"A simple and effective method to analyze field distribution in curved dielectric waveguides","authors":"M. Kaiyu, Xu Shanjia","doi":"10.1109/APS.2001.959710","DOIUrl":"https://doi.org/10.1109/APS.2001.959710","url":null,"abstract":"Field distributions of a curved dielectric waveguide with rectangular cross-section are investigated by a network method combined with a modified EDC approximation. It is shown that the field maximum tends to outwardly shift. Field profiles in the inner and outer space regions of the waveguide are also drawn. Results of numerical analysis show very good agreement with experimental results while the present approach is simpler and more convenient compared with those applying the WKB method.","PeriodicalId":159827,"journal":{"name":"IEEE Antennas and Propagation Society International Symposium. 2001 Digest. Held in conjunction with: USNC/URSI National Radio Science Meeting (Cat. No.01CH37229)","volume":"76 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2001-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121525631","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}
IEEE Antennas and Propagation Society International Symposium. 2001 Digest. Held in conjunction with: USNC/URSI National Radio Science Meeting (Cat. No.01CH37229)
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