A description is given of image resolving, shifted array correlation (ISAC), an angle-of-arrival technique that computes image signal reflection coefficients that maximize the correlation as the elevation sector is scanned by steering vectors. Accurate low-elevation-angle resolution is obtained by shifting the array to increase the effective aperture. Computer simulation results are presented to show some of the performance characteristics of the ISAC technique as applied to the low-elevation target problem. Numerical analysis predicts the experimental problem of resolving low-elevation-angle radar targets. Target resolution near the horizon, on the order of 1/8 of an array beamwidth, requires array signal-to-noise ratios in excess of 30 dB.<>
{"title":"Resolution of low elevation radar targets and images using a shifted array correlation technique","authors":"K. Struckman","doi":"10.1109/APS.1989.135069","DOIUrl":"https://doi.org/10.1109/APS.1989.135069","url":null,"abstract":"A description is given of image resolving, shifted array correlation (ISAC), an angle-of-arrival technique that computes image signal reflection coefficients that maximize the correlation as the elevation sector is scanned by steering vectors. Accurate low-elevation-angle resolution is obtained by shifting the array to increase the effective aperture. Computer simulation results are presented to show some of the performance characteristics of the ISAC technique as applied to the low-elevation target problem. Numerical analysis predicts the experimental problem of resolving low-elevation-angle radar targets. Target resolution near the horizon, on the order of 1/8 of an array beamwidth, requires array signal-to-noise ratios in excess of 30 dB.<<ETX>>","PeriodicalId":11330,"journal":{"name":"Digest on Antennas and Propagation Society International Symposium","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1989-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"77613798","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}
An approach is developed which expands the diffracted field as a bundle of inhomogeneous plane waves each of which is diffracted separately. The analysis leads to a result in terms of double Fresnel integrals which can be evaluated efficiently by various means. In addition to geometrical generality, this double diffraction coefficient is simple to apply, since it is directly related to the product of two single diffraction coefficients. Each of 16 terms of the new formulation corresponds to one of the 16 terms obtained when two single-wedge diffraction coefficients are multiplied as in a mechanical application of UTD (uniform theory of diffraction) to double-wedge diffraction. For terms not in transition, the new formulation reduces to the UTD product, term by term. The geometry of two perfectly conducting wedges is shown, and their separation is indicated. A comparison between the new theory and the straightforward application of UTD is presented.<>
{"title":"A uniform double diffraction coefficient","authors":"M. Schneider, R. Luebbers","doi":"10.1109/APS.1989.134942","DOIUrl":"https://doi.org/10.1109/APS.1989.134942","url":null,"abstract":"An approach is developed which expands the diffracted field as a bundle of inhomogeneous plane waves each of which is diffracted separately. The analysis leads to a result in terms of double Fresnel integrals which can be evaluated efficiently by various means. In addition to geometrical generality, this double diffraction coefficient is simple to apply, since it is directly related to the product of two single diffraction coefficients. Each of 16 terms of the new formulation corresponds to one of the 16 terms obtained when two single-wedge diffraction coefficients are multiplied as in a mechanical application of UTD (uniform theory of diffraction) to double-wedge diffraction. For terms not in transition, the new formulation reduces to the UTD product, term by term. The geometry of two perfectly conducting wedges is shown, and their separation is indicated. A comparison between the new theory and the straightforward application of UTD is presented.<<ETX>>","PeriodicalId":11330,"journal":{"name":"Digest on Antennas and Propagation Society International Symposium","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1989-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80204153","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 authors present early results of a numerical analysis of a general patch antenna array with coplanar microstrip feed lines. First, the input impedance and resonant frequency of an isolated patch element with microstrip line feed on a lossless substrate are considered, followed by a discussion of the mutual coupling between two identical patch antennas. The impedance matrix and the feed model criteria which are critical in predicting the input impedance and mutual coupling, are also mentioned. A more accurate feed model for the microstrip line-fed patch element is currently being developed based upon experiments using an HP-8510B network analyzer.<>
{"title":"Mutual coupling of two microstrip line-fed patch antennas","authors":"R. Fralich, J. Wang, J. Litva","doi":"10.1109/APS.1989.134712","DOIUrl":"https://doi.org/10.1109/APS.1989.134712","url":null,"abstract":"The authors present early results of a numerical analysis of a general patch antenna array with coplanar microstrip feed lines. First, the input impedance and resonant frequency of an isolated patch element with microstrip line feed on a lossless substrate are considered, followed by a discussion of the mutual coupling between two identical patch antennas. The impedance matrix and the feed model criteria which are critical in predicting the input impedance and mutual coupling, are also mentioned. A more accurate feed model for the microstrip line-fed patch element is currently being developed based upon experiments using an HP-8510B network analyzer.<<ETX>>","PeriodicalId":11330,"journal":{"name":"Digest on Antennas and Propagation Society International Symposium","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1989-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80265983","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 numerical technique has recently been developed to deal with printed circuit antennas with arbitrary shapes via the method of moments (see H. Nakano et al. 1987). However, the drawback of this numerical approach is the lack of efficient evaluation of impedance matrix elements when the moment method is enforced. It is shown that the image extraction method of C.L. Chi (1987) can be used to enhance the computation efficiency significantly. The analysis is based on the decomposition of the dynamic Green's function. One of the applications of this efficient numerical technique is to study the radiation characteristics of a printed spiral antenna. A printed spiral antenna composed of semi-ellipses is considered as a numerical example.<>
最近发展了一种数值技术，通过矩量法处理任意形状的印刷电路天线(见H. Nakano et al. 1987)。然而，这种数值方法的缺点是，当采用矩量法时，缺乏对阻抗矩阵元素的有效计算。结果表明，采用C.L. Chi(1987)的图像提取方法可以显著提高计算效率。分析是基于动态格林函数的分解。这种有效的数值技术的应用之一是研究印刷螺旋天线的辐射特性。以半椭圆结构的印刷螺旋天线为算例。
{"title":"On the modeling of arbitrarily-shaped printed circuit antennas","authors":"C. Chi, J. A. Castaneda","doi":"10.1109/APS.1989.135058","DOIUrl":"https://doi.org/10.1109/APS.1989.135058","url":null,"abstract":"A numerical technique has recently been developed to deal with printed circuit antennas with arbitrary shapes via the method of moments (see H. Nakano et al. 1987). However, the drawback of this numerical approach is the lack of efficient evaluation of impedance matrix elements when the moment method is enforced. It is shown that the image extraction method of C.L. Chi (1987) can be used to enhance the computation efficiency significantly. The analysis is based on the decomposition of the dynamic Green's function. One of the applications of this efficient numerical technique is to study the radiation characteristics of a printed spiral antenna. A printed spiral antenna composed of semi-ellipses is considered as a numerical example.<<ETX>>","PeriodicalId":11330,"journal":{"name":"Digest on Antennas and Propagation Society International Symposium","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1989-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80298808","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 a multipath environment, electromagnetic propagation is degraded by obstacles that causes reflection, refraction, diffraction and scattering. To quantify this degradation, the envelope of the fast component signal is compared with well-established models, such as the Rice distribution. The author proposes a simple, rapid, and precise method to determine the value of a of the Rice distribution. This technique is based on the use of a chart specially developed for this purpose. It becomes then merely sufficient to plot a best fit horizontal line to obtain the value of a. Experimental results obtained with this method are presented.<>
{"title":"A rapid channel characterization method using a new Rice distribution chart","authors":"L. Kaliouby","doi":"10.1109/APS.1989.134813","DOIUrl":"https://doi.org/10.1109/APS.1989.134813","url":null,"abstract":"In a multipath environment, electromagnetic propagation is degraded by obstacles that causes reflection, refraction, diffraction and scattering. To quantify this degradation, the envelope of the fast component signal is compared with well-established models, such as the Rice distribution. The author proposes a simple, rapid, and precise method to determine the value of a of the Rice distribution. This technique is based on the use of a chart specially developed for this purpose. It becomes then merely sufficient to plot a best fit horizontal line to obtain the value of a. Experimental results obtained with this method are presented.<<ETX>>","PeriodicalId":11330,"journal":{"name":"Digest on Antennas and Propagation Society International Symposium","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1989-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80404384","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 edge diffraction corrections to the physical optics approximation for impedance wedges and for a plane wave of an arbitrary angle of incidence are determined. The proposed method constitutes a generalization of Ufimtsev's physical theory of diffraction (1982) valid for perfectly conducting objects. Numerical results are presented for the resulting diffraction coefficients for some representative values of face impedances, incidence angles, and wedge opening angles.<>
{"title":"Physical theory of diffraction for scattering of electromagnetic waves of an arbitrary incidence angle from impedance edges","authors":"E. Bleszynski, H. Tran, M. Bleszynski","doi":"10.1109/APS.1989.134796","DOIUrl":"https://doi.org/10.1109/APS.1989.134796","url":null,"abstract":"The edge diffraction corrections to the physical optics approximation for impedance wedges and for a plane wave of an arbitrary angle of incidence are determined. The proposed method constitutes a generalization of Ufimtsev's physical theory of diffraction (1982) valid for perfectly conducting objects. Numerical results are presented for the resulting diffraction coefficients for some representative values of face impedances, incidence angles, and wedge opening angles.<<ETX>>","PeriodicalId":11330,"journal":{"name":"Digest on Antennas and Propagation Society International Symposium","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1989-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81441657","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}
An attempt is made to establish the validity of the TD-FD (time-domain-finite-difference) method in modeling circuit components for MMIC-CAD (monolithic microwave integrated circuit/computer-aided design) method applications. Numerical results are presented for a microstrip open end on an alumina substrate ( epsilon /sub r/=9.6). It is shown that the TD-FD approach is capable of calculating the microstrip end effect over a large frequency range. This method, with minor modifications, can also be used to model other microstrip discontinuities.<>
{"title":"Time-domain finite difference approach for the modeling of microstrip components","authors":"X. Zhang, K. Mei","doi":"10.1109/APS.1989.134898","DOIUrl":"https://doi.org/10.1109/APS.1989.134898","url":null,"abstract":"An attempt is made to establish the validity of the TD-FD (time-domain-finite-difference) method in modeling circuit components for MMIC-CAD (monolithic microwave integrated circuit/computer-aided design) method applications. Numerical results are presented for a microstrip open end on an alumina substrate ( epsilon /sub r/=9.6). It is shown that the TD-FD approach is capable of calculating the microstrip end effect over a large frequency range. This method, with minor modifications, can also be used to model other microstrip discontinuities.<<ETX>>","PeriodicalId":11330,"journal":{"name":"Digest on Antennas and Propagation Society International Symposium","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1989-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81697401","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}
Large reflector antennas subjected to dead load, wind load, etc. experience structural deformations which cause degradations in radiation patterns. In the present work, variations of far-field radiation patterns of reflector antennas due to symmetrical (n=0) and antisymmetrical (n=1) deformation are numerically analyzed. Two types of parabolic antennas are used as the illustrative models. The antisymmetrical deformations are shown to have a stronger influence on the variations of radiation patterns.<>
{"title":"Variation of far-field radiation patterns of reflectors by structural deformation","authors":"F. Guan, Y. Hangai","doi":"10.1109/APS.1989.134671","DOIUrl":"https://doi.org/10.1109/APS.1989.134671","url":null,"abstract":"Large reflector antennas subjected to dead load, wind load, etc. experience structural deformations which cause degradations in radiation patterns. In the present work, variations of far-field radiation patterns of reflector antennas due to symmetrical (n=0) and antisymmetrical (n=1) deformation are numerically analyzed. Two types of parabolic antennas are used as the illustrative models. The antisymmetrical deformations are shown to have a stronger influence on the variations of radiation patterns.<<ETX>>","PeriodicalId":11330,"journal":{"name":"Digest on Antennas and Propagation Society International Symposium","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1989-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"81930407","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 authors outline the fundamentals of phased-array beamforming and indicate how these concepts can use optical control signaling. They explore a simple parallel optical processing scheme which has the potential of being extended to the control of larger phased-array systems. The method of very rapid control adjustment examined here has the potential of providing almost instantaneous beam reconfiguration, in very large phased arrays, without the heavy computational burden normally associated with such systems.<>
{"title":"Optical techniques for reconfiguring microwave phased arrays","authors":"N. Jespersen, P. Herczfeld","doi":"10.1109/APS.1989.134710","DOIUrl":"https://doi.org/10.1109/APS.1989.134710","url":null,"abstract":"The authors outline the fundamentals of phased-array beamforming and indicate how these concepts can use optical control signaling. They explore a simple parallel optical processing scheme which has the potential of being extended to the control of larger phased-array systems. The method of very rapid control adjustment examined here has the potential of providing almost instantaneous beam reconfiguration, in very large phased arrays, without the heavy computational burden normally associated with such systems.<<ETX>>","PeriodicalId":11330,"journal":{"name":"Digest on Antennas and Propagation Society International Symposium","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1989-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85242776","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 characteristics of circular patch antennas mounted on cylindrical surfaces are analyzed. To illustrate the effect of curvature, a patch radius b=2 cm is considered. The effects of curvature on the patterns, Q-factors, and input impedances are shown.<>
{"title":"On the cylindrical-circular patch antenna","authors":"K. Luk, K. Lee","doi":"10.1109/APS.1989.135057","DOIUrl":"https://doi.org/10.1109/APS.1989.135057","url":null,"abstract":"The characteristics of circular patch antennas mounted on cylindrical surfaces are analyzed. To illustrate the effect of curvature, a patch radius b=2 cm is considered. The effects of curvature on the patterns, Q-factors, and input impedances are shown.<<ETX>>","PeriodicalId":11330,"journal":{"name":"Digest on Antennas and Propagation Society International Symposium","volume":null,"pages":null},"PeriodicalIF":0.0,"publicationDate":"1989-06-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80872257","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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