GTD analysis of the radiation patterns of conical horns
TL;DR: In this article, far-field radiation patterns of conical horns of arbitrary flare angles excited in the TE-11 mode were obtained employing the geometric theory of diffraction (GTD) based on the theory of Kouyoumjian and Pathak and the slope diffraction technique.
Abstract: The far-field radiation patterns of conical horns of arbitrary flare angles excited in the TE_{11} mode are obtained employing the geometric theory of diffraction (GTD) based on the theory of Kouyoumjian and Pathak [3] and the slope diffraction technique [4]. The analysis presented enables one to predict accurately radiation patterns over the main beam, near and far sidelobes, and the becklobe of the horn. Validity of the analysis is established by satisfactory agreement between the calculated and measured patterns of an experimental conical horn. The radiation patterns of wide-flare corrugated conical horns excited in the HE_{11} mode of operation have also been calculated over the main beam, which contains most of the radiated energy (up to -40 dB with respect to boresight field), employing slope diffraction technique, and a good agreement is noticed between the calculated and measured radiation patterns.
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TL;DR: In this article, the electromagnetic field propagating up a cone having an arbitrary wall impedance is found using an asymptotic solution, and three special cases are considered: the smooth metal wall, the corrugated wall, and the metal wall with a lossy-dielectric lining.
Abstract: The electromagnetic fields propagating up a cone having an arbitrary wall impedance are found using an asymptotic solution. Three special cases are then considered: the smooth-metal wall, the corrugated wall, and the metal wall with a lossy-dielectric lining. The last case, in the form of an absorber-lining is then shown to behave like a corrugated horn since it too provides a highly tapered E -plane and H -plane aperture distribution. Furthermore, it does this over a much larger bandwidth, over 3:1, with negligible gain drop.
23Â citations
TL;DR: In this article, the impact of flnite ground plane edge difiractions on the amplitude patterns of aperture antennas is examined, using the Uniform Theory of Difiraction (UTD) and the Geometrical Optics (GO) methods.
Abstract: In this study, the impact of flnite ground plane edge difiractions on the amplitude patterns of aperture antennas is examined. The Uniform Theory of Difiraction (UTD) and the Geometrical Optics (GO) methods are utilized to calculate the amplitude patterns of a conical horn, and rectangular and circular waveguide apertures mounted on square and circular flnite ground planes. The electric fleld distribution over the antenna aperture is obtained by a modal method, and then it is employed to calculate the geometrical optics fleld using the aperture integration method. The UTD is then applied to evaluate the difiraction from the ground planes' edges. Far-zone amplitude patterns in the E and H planes are flnally obtained by the vectorial summation of the GO and UTD flelds. In this paper, to accurately predict the H-plane amplitude patterns of circular and rectangular apertures mounted on square ground planes, the E-plane edge difiractions need to be included because the E-plane edge difiractions are much more intense than those of the H-plane edge regular and slope difiractions. Validity of the analysis is established by satisfactory agreement between the predicted and measured data and those simulated by Ansoft's High Frequency Structure Simulator (HFSS). Good agreement is observed for all cases considered.
10Â citations
TL;DR: Two simulation techniques for modeling periodic structures with three-dimensional elements in general are presented, one based on the Method of Moments (MoM) and the other a Finite Difierence Time Domain (FDTD)-based approach, which is well suited for handling arbitrary, inhomogeneous, three- dimensional periodic structures.
Abstract: In this paper we present two simulation techniques for modeling periodic structures with three-dimensional elements in general. The flrst of these is based on the Method of Moments (MoM) and is suitable for thin-wire structures, which could be either PEC or plasmonic, e.g., nanowires at optical wavelengths. The second is a Finite Difierence Time Domain (FDTD)-based approach, which is well suited for handling arbitrary, inhomogeneous, three-dimensional periodic structures. Neither of the two approaches make use of the traditional Periodic Boundary Conditions (PBCs), and are free from the di-culties encountered in the application of the PBC, as for instance slowness in convergence (MoM) and instabilities (FDTD).
3Â citations
TL;DR: In this paper, an analytical procedure for predicting accurately the E-plane patterns of conical horns with moderate aperture widths based on uniform geometrical theory of diffraction (UGTD) and supported by measured data is presented.
Abstract: An analytical procedure for predicting accurately the E -plane patterns of conical horns with moderate aperture widths ( ka ), based on uniform geometrical theory of diffraction (UGTD) and supported by measured data, is presented. This analysis predicts the E -plane patterns more accurately (over the main beam) than the one presented earlier.
2Â citations
TL;DR: In this article, a double conical horn which consists of two coaxially arranged conical horns is analyzed by means of a mode-matching procedure, and it can be dimensioned to produce nearly identical radiation characteristics at two different frequencies.
Abstract: A double conical horn which consists of two coaxially arranged conical horns is analyzed by means of a mode-matching procedure. It can be dimensioned, to produce nearly identical radiation characteristics at two different frequencies. Therefore the double conical horn can serve as a feed of reflector antennas in order to double the transmission capacity of the antenna system. A design procedure for this feed is given
References
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Book•
01 Jun 1961
TL;DR: In this paper, a revised version of the Revised edition of the book has been published, with a new introduction to the concept of plane wave functions and spherical wave functions, as well as a detailed discussion of the properties of these functions.
Abstract: Foreword to the Revised Edition. Preface. Fundamental Concepts. Introduction to Waves. Some Theorems and Concepts. Plane Wave Functions. Cylindrical Wave Functions. Spherical Wave Functions. Perturbational and Variational Techniques. Microwave Networks. Appendix A: Vector Analysis. Appendix B: Complex Permittivities. Appendix C: Fourier Series and Integrals. Appendix D: Bessel Functions. Appendix E: Legendre Functions. Bibliography. Index.
5,655Â citations
01 Nov 1974
TL;DR: In this article, a compact dyadic diffraction coefficient for electromagnetic waves obliquely incident on a curved edse formed by perfectly conducting curved plane surfaces is obtained, which is based on Keller's method of the canonical problem, which in this case is the perfectly conducting wedge illuminated by cylindrical, conical, and spherical waves.
Abstract: A compact dyadic diffraction coefficient for electromagnetic waves obliquely incident on a curved edse formed by perfectly conducting curved ot plane surfaces is obtained. This diffraction coefficient remains valid in the transition regions adjacent to shadow and reflection boundaries, where the diffraction coefficients of Keller's original theory fail. Our method is based on Keller's method of the canonical problem, which in this case is the perfectly conducting wedge illuminated by plane, cylindrical, conical, and spherical waves. When the proper ray-fixed coordinate system is introduced, the dyadic diffraction coefficient for the wedge is found to be the sum of only two dyads, and it is shown that this is also true for the dyadic diffraction coefficients of higher order edges. One dyad contains the acoustic soft diffraction coefficient; the other dyad contains the acoustic hard diffraction coefficient. The expressions for the acoustic wedge diffraction coefficients contain Fresenel integrals, which ensure that the total field is continuous at shadow and reflection boundaries. The diffraction coefficients have the same form for the different types of edge illumination; only the arguments of the Fresnel integrals are different. Since diffraction is a local phenomenon, and locally the curved edge structure is wedge shaped, this result is readily extended to the curved wedge. It is interesting that even though the polarizations and the wavefront curvatures of the incident, reflected, and diffracted waves are markedly different, the total field calculated from this high-frequency solution for the curved wedge is continuous at shadow and reflection boundaries.
2,582Â citations
"GTD analysis of the radiation patte..." refers methods in this paper
...Ahtract-The far-field radiation patterns of conical horns of arbitrary flare angles excited in the TEll mode are obtained employing the geometric theory of diffraction (GTD) based on the theory of Kouyoumjian and Pathak [ 3 ] and the slope diffraction technique [4]....
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...In this paper a GTD analysis of radiation pattern based on the theory of Kouyoumjian and Pathak [ 3 ] and the slope diffraction formulation of Mentzer et al. [4], valid for both conical and corrugated conical horns of small- and wide-flare angle, is presented....
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TL;DR: In this paper, the authors used the geometrical theory of diffraction to obtain the backscattered field for plane-wave incidence on a target with particular emphasis on those regions that are usually avoided, namely, the caustic region and its immediate vicinity.
Abstract: The fields diffracted by a body made up of finite axially symmetric cone frustums are obtained using the concepts of the geometrical theory of diffraction. The backscattered field for plane-wave incidence on such a target is obtained with particular emphasis on those regions that are usually avoided, namely, the caustic region and its immediate vicinity. The method makes use of equivalent electric and magnetic current sources which are incorporated in the geometrical theory of diffraction. This solution is such that it is readily incorporated in a general computer program, rather than requiring that a new program be written for each shape. Several results, such as the cone, the cylinder and the conically capped cylinder, are given. In addition, the method is readily applied to antenna problems. An example which is reported consists of the radiation by a stub over a circular ground plane. This present theory yields quite good agreement with experimental results reported by Lopez, whereas the original theory given by Lopez is in error by as much as 10 dB.
191Â citations