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Journal ArticleDOI

On the fields in a conical horn having an arbitrary wall impedance

01 Sep 1986-IEEE Transactions on Antennas and Propagation (IEEE)-Vol. 34, Iss: 9, pp 1092-1098
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.
Citations
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Journal ArticleDOI
TL;DR: The widely used transversely corrugated surfaces and other alternative surfaces having the same anisotropic surface impedance deserve a common name as discussed by the authors, and it is proposed to call them soft surfaces by analogy with the soft surfaces in acoustics.
Abstract: The widely used transversely corrugated surfaces and other alternative surfaces having the same anisotropic surface impedance deserve a common name. Here it is proposed to call them soft surfaces by analogy with the soft surfaces in acoustics. In the same way artificially hard surfaces are defined. Cylindrical hard waveguides of any cross-sectional shape can support TEM waves.

349 citations

Patent
20 Sep 2001
TL;DR: In this article, a hog-horn antenna is designed to produce substantially equal gains for orthogonal polarizations, either simultaneously or separately, by corrugating or absorber-lining the surfaces of portions of the antenna.
Abstract: A hog-horn antenna for producing two orthogonally polarized signals. The elevation plane pattern of each signal can be made to have virtually any shape, but is typically of a substantially cosecant-squared shape. In providing for the dual-polarization capability, the hog-horn antenna is designed to produce substantially equal gains for orthogonal polarizations, either simultaneously or separately. Two techniques to substantially equate the elevation plane radiation patterns of the two polarizations include corrugating or absorber-lining the surfaces of portions of the hog-horn antenna. Azimuthal pattern control may be achieved by corrugated/absorber lined flanges.

155 citations

Journal ArticleDOI
TL;DR: Horn antennas with soft and hard boundaries are analyzed and the dependency between the edge taper directivity, and sidelobes is calculated based on the solution to the spherical hybrid modes in a conical horn with arbitrary wall impedances.
Abstract: Horn antennas with soft and hard boundaries are analyzed. A soft boundary which exists in classical hybrid-mode horns gives zero field intensity at the wall. A hard boundary corresponds to a uniform field distribution over the horn aperture. Soft and hard horn antennas are compared with respect to directivity, sidelobes, and beamwidth. The dependency between the edge taper directivity, and sidelobes is also calculated based on the solution to the spherical hybrid modes in a conical horn with arbitrary wall impedances. This makes it possible to study how to compromise between directivity and sidelobes. Also discussed is how the different wall impedances may be realized, and some preliminary experimental work on hard horns is presented. >

102 citations

Journal ArticleDOI
TL;DR: Strip-loaded horn with transverse (soft) and longitudinal (hard) strips are analyzed theoretically in this article, based on a circular cylindrical and uniform waveguide model with a periodic strip structure.
Abstract: Strip-loaded horns with transverse (soft) and longitudinal (hard) strips are analyzed theoretically The method is based on a circular cylindrical and uniform waveguide model with a periodic strip structure The field is represented by an infinite series of space harmonics (Floquet modes) in the air-filled central region and in the dielectrically filled wall region The tangential field is forced to be continuous across the air-dielectric boundary The propagation constant and the total field (including the hybrid factor) can be determined by solving the resulting matrix equations The convergence of the solution has been accelerated by calculating the higher-order terms analytically It is shown that the soft-strip-loaded horn in principle exhibits the same electrical behavior as a corrugated horn The horn represents an interesting alternative to the corrugated horn in wide-band or dual-band applications, in particular for millimeter waves and for lightweight applications onboard satellites The hard-strip-loaded horn has potentially high gain and low cross polarization over a certain frequency range, dependent on the horn dimensions, thickness of the dielectric wall and on how strongly the stripline modes are being excited >

48 citations

Journal ArticleDOI
TL;DR: In this article, a rectangular waveguide with a lossy flange coating is studied both analytically and experimentally and an analytic method using Fourier analysis and an impedance boundary condition is proposed.
Abstract: The radiation from a rectangular waveguide with a lossy flange coating is studied both analytically and experimentally. An analytic method using Fourier analysis and an impedance boundary condition is proposed. The experiment was performed using a flange covered with a rubber ferrite sheet at an X-band frequency. The numerical and measured results agree well and show that the lossy flange improves the E-plane radiation pattern and the crosspolar radiation. A boresight gain drop of about 2 db is predicted theoretically and measured experimentally. >

35 citations

References
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Journal ArticleDOI
01 Sep 1971
TL;DR: In this article, the propagation and radiation properties of corrugated waveguides were investigated and the attenuation of the dominant HE11 mode was shown to be less than that of the H11 mode in a uniform waveguide over at least a 2:1 frequency bandwidth.
Abstract: An investigation of the propagation and radiation behaviour of circular corrugated waveguides is described. Particular attention is given to modes of unity azimuthal dependence because of their importance in antennafeed applications. It is shown that the radiation pattern of a corrugated waveguide exhibits nearly perfect symmetry over a 1.5:1 frequency band, and, when the corrugations are approximately λ/4 deep, the pattern is symmetric and there is no crosspolarised component of radiated field. The attenuation of the dominant HE11 mode is investigated theoretically and is shown to be less than that of the H11mode in a uniform waveguide over at least a 2:1 frequency bandwidth. An important similarity is described between the propagation behaviour of a corrugated waveguide and that of a dielectric rod of low relative permittivity, such as those used in fibre optics and optical waveguides. Finally, the determination of the input voltage standing-wave ratio (v.s.w.r.) at the junction between homogeneous and corrugated waveguides is theoretically and experimentlly studied.

121 citations

Journal ArticleDOI
TL;DR: In this article, a simpler solution for spherical hybrid modes in corrugated conical horns has been shown to have a deviation from the rigorous solution of less than 0.7 dB for the case considered by Clarricoats.
Abstract: A simpler solution for spherical hybrid modes in corrugated conical horns has been shown to have a deviation from the rigorous solution of less than 0.7 dB for the case considered by Clarricoats. Expressions for the radiation pattern and gain of such a horn with small flare angle have been obtained under balanced hybrid conditions.

33 citations

Journal ArticleDOI
TL;DR: Theoretical radiation patterns are predicted and compared with those obtained experimentally in this article, where it is shown that aperture efficiencies of the order of 91-96 percent may be obtained.
Abstract: Theoretical radiation patterns are predicted and compared with those obtained experimentally. The measured peak cross-polarization level is less than -29 dB at 9 GHz. It is shown that aperture efficiencies of the order of 91-96 percent may be obtained.

19 citations

Journal ArticleDOI
TL;DR: In this paper, the authors investigated the electromagnetic field propagation through a parallel-plate waveguide having absorber walls, and showed that the dominant TM/sup e/sub 10/ and TE/sup E/sub sub 10/ modes can propagate independently with both having a highly-tapered (cosine-type) transverse distribution, phase velocity slightly exceeding the speed of light, and very low axial attenuation, especially for a wall-spacing large as compared to a free-space wavelength.
Abstract: The electromagnetic fields that can propagate through a parallel-plate waveguide having absorber walls are investigated, and it is shown that dominant TM/sup e//sub 10/ and TE/sup e//sub 10/ modes can propagate independently with both having a highly-tapered (cosine-type) transverse distribution, a phase velocity slightly exceeding the speed of light, and very low axial attenuation, especially for a wall-spacing large as compared to a free-space wavelength. In other words, such an absorber-guide acts life a corrugated waveguide having "lambda/4" teeth (balanced-hybrid mode) but it does so over virtually an unlimited bandwidth and with little sensitivity to the absorber's characteristics.

12 citations

Journal ArticleDOI
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