GTD analysis of the E-plane patterns of conical horns
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.
Citations
More filters
TL;DR: An error in the geometrical theory of diffraction (GTD) near-field analysis of a conical horn published earlier is pointed out in this paper, and the correct expression for the near field patterns for the conical Horn is presented.
Abstract: An error in the geometrical theory of diffraction (GTD) near-field analysis of a conical horn published earlier is pointed out. This error is corrected, and the correct expression for the near-field patterns for the conical horn is presented. Computations based on the corrected formulas correlate better with results based on measurement as well as aperture integration technique [4].
3 citations
TL;DR: In this paper, the principal plane near-field pattern of conical and corrugated conical horns with small and wide flare angles was analyzed in the dominant mode using the uniform theory of diffraction.
Abstract: For original paper see ibid., vol.AP-25, no.3, p.447 (1977) which presents a novel technique for the analysis of the principal plane near-field patterns of conical and corrugated conical horns with small and wide flare angles excited in the dominant mode using the uniform theory of diffraction (UTD). The authors apply a slope diffraction correction, which is necessary in cases where the incident field is rapidly varying at the edge
References
More filters
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.
2,582 citations
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.
191 citations
TL;DR: In this article, the problem of a half plane illuminated by a nonplanar wave is investigated using the concept of the plane wave spectral representation, and a new higher-order asymptotic solution for the total field up to and including terms of order k−5/2 relative to the incident field is derived.
Abstract: The knowledge of high-frequency diffraction of an arbitrary wave incident on an edge is important in many applications, such as antennas mounted on aircraft and reflector antennas illuminated by complex feeds. In this paper the problem of a half plane illuminated by a nonplanar wave is investigated using the concept of the plane wave spectral representation. For large wave number k, a new higher-order asymptotic solution for the total field up to and including terms of order k−5/2 relative to the incident field is derived. The behavior of the solution for the observation points which coincide with shadow boundary directions of a multipole line source is discussed in detail. Furthermore, numerical solution of the field integral representation is constructed for the observation angles in the transition regions. The results are compared with those of the Geometrical Theory of Diffraction (GTD), the Uniform Asymptotic Theory (UAT), the Uniform Theory of Diffraction (UTD) and the Modified Slope Diffraction (MSD).
51 citations
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.
7 citations