# Hybrid modes in corrugated conical horns

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.

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TL;DR: Reflector antennas have been used since the radio pioneering era of Lodge, Hertz, and Marconi, but it took the exigent demands of radar in World War II to stimulate a real development in the reflector art as discussed by the authors.

Abstract: Reflector antennas have been used since the radio pioneering era of Lodge, Hertz, and Marconi, but it took the exigent demands of radar in World War II to stimulate a real development in the reflector art. Subsequent interest in the science of radio astronomy and the inception of microwave ground communication links were responsible for a burgeoning growth in the field, so that in the 1940s and 1950s the design principles and requirements for prime focus fed systems were well established. Cassegrain, or secondary focus systems, and horn reflectors came into prominence in the early 1960s with the advent of satellite tracking and communication networks. The desire to maximize the gain, or the gain-temperature ratio, then led to development of sophisticated techniques for properly shaping the illumination over the reflector aperture in order to maximize efficiency and minimize spillover, among them being the shaping of the sub-reflector in Cassegrain systems and the use of multimode and hybrid mode feed horns. Not all reflector antennas utilize paraboloidal surfaces. Some recent developments in line source feeds make the spherical reflector attractive for scanning applications and the conical reflector for deployable, space-borne antennas. The large 1000-foot diameter reflector at Arecibo is a well known example of the former. Although some extremely large spaceborne reflector antennas have been proposed and studied, the largest now in use appears to be the unfurlable 30-foot reflector carried by ATS-6. Finally, some gain comparisons are given for a few of the (electrically) largest reflectors that have been built both for radio astronomy and for space communications. If some milestones in reflector development have been overlooked it is due to the limitations inherent in a review paper.

73 citations

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TL;DR: In this paper, the effect of the dominant mode shape with frequency and mode conversion along the horn taper and at waveguide transitions at the horn input on return loss and radiation patterns is investigated.

Abstract: Microwave antennas are often required to carry signals simultaneously over a broad range of frequencies–e.g., the combined td-2 and th common carrier bands encompass a total frequency ratio of about 1.8 to 1 as do the combined 18- and 30-GHz bands. To achieve these bandwidths, an efficient broadband feed horn is required. The corrugated (hybrid-mode) horn is a leading candidate, but it is not immune to some cross-polarization coupling, input reflection, and pattern asymmetry. These problems are introduced mainly by two phenomena: variation of the dominant mode shape with frequency and mode conversion along the horn taper and at waveguide transitions at the horn input. Simple formulas for computing the magnitude of these phenomena and their effects on return loss and radiation patterns are given.

62 citations

### Cites background from "Hybrid modes in corrugated conical ..."

...Let ii be the propagation constant in the ζ direction, ß-k cosfli, (9) and assume 0\ is real, so that (i < k....

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TL;DR: In this article, a corrugated feed with nearly ideal radiation characteristics from 17 GHz to 29 GHz has been built using a novel fabrication technique, where the bandwidth of single-mode operation was maximized by properly choosing the input parameters of the feed.

Abstract: A corrugated feed with nearly ideal radiation characteristics from 17 GHz to 29 GHz has been built using a novel fabrication technique. The bandwidth of single-mode operation was maximized by properly choosing the input parameters of the feed. As a result, only the fundamental mode can propagate at the input from 19 GHz to 28.8 GHz. In this frequency range, the far field is essentially polarized in one direction. At frequencies higher than 28.8 GHz, there is a cross-polarized component caused by an unwanted mode. An approximate calculation of the power in this mode is given. A simple formula for the input reflection coefficient is provided. Results are included that show how to compute mode conversion in a conical taper, cross polarization from a corrugated horn, including contributions from spurious modes, and the reflection coefficient from the smooth-guide to corrugated-guide transition. Comparison of theory and experiment shows good agreement.

44 citations

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TL;DR: In this article, an integral equation solution was used to study the influence of corrugation density and tooth thickness on the power loss, surface current, and the scattering from a groundplane-corrugated surface junction.

Abstract: Corrugated horns involve a junction between the corrugated surface and a conducting groundplane. Proper horn design requires an understanding of the electromagnetic properties of the corrugated surface and this junction. An integral equation solution has been used to study the influence of corrugation density and tooth thickness on the power loss, surface current, and the scattering from a groundplane-corrugated surface junction.

39 citations

##### References

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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.

5,655 citations

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01 Jan 1949

TL;DR: This book discusses microwave antenna design problems, circuit relations, reciprocity theorems, and antenna measurements - techniques.

Abstract: * Chapter 1: Survey of microwave antenna design problems * Chapter 2: Circuit relations, reciprocity theorems * Chapter 3: Radiation from current distributions * Chapter 4: Wavefronts and rays * Chapter 5: Scattering and diffraction * Chapter 6: Aperture illumination and antenna patterns * Chapter 7: Microwave transmission lines * Chapter 8: Microwave dipole antennas and feeds * Chapter 9: Linear-array antennas and feeds * Chapter 10: Waveguide and horn feeds * Chapter 11: Dielectric and metal-plate lenses * Chapter 12: Pencil-beam and simple fanned-beam antennas * Chapter 13: Shaped-beam antennas * Chapter 14: Antenna installation problems * Chapter 15: Antenna measurements - techniques * Chapter 16: Antenna measurements - equipment

1,504 citations

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TL;DR: Symmetrical radiation feed patterns which are consequence of specified form of hybrid mode fields as disclosed by focal plane analysis are described in this article, where the authors show that the feed pattern is a consequence of the hybrid mode field.

Abstract: Symmetrical radiation feed patterns which are consequence of specified form of hybrid mode fields as disclosed by focal plane analysis

160 citations

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Bell Labs

^{1}TL;DR: In this article, it was shown that these methods are preferable to those based on the Kirchhoff formula, in some instances, at least, is obviously unreasonable (Appendix III) and that the calculations of diffracted fields and radiation fields, based either on the equivalence principle or on the more general induction theorem, depend upon a priori verifiable approximations to the actual fields in the neighborhoods of the sources of the diffracted and radiated waves.

Abstract: Inasmuch as it is rarely possible to treat diffraction of electromagnetic waves exactly, the Kirchhoff formulation of Huygens' Principle has been frequently used in approximate calculations. If the Kirchhoff formula is applied directly to the field intensities of the incident wave over the aperture, the diffracted field is found to be inconsistent with Maxwell's equations. If, on the other hand, this formula is applied to some auxiliary vector potential from which the diffracted field is subsequently deduced by differentiation, the result (although consistent with Maxwell's equations) depends on the particular choice of the auxiliary vector and in some instances, at least, is obviously unreasonable (Appendix III). The calculations of diffracted fields and radiation fields, based either on the Equivalence Principle or on the more general Induction Theorem, depend upon a priori verifiable approximations to the actual fields in the neighborhoods of the sources of the diffracted and radiated waves. For this reason we feel that these methods are preferable to those based on the Kirchhoff formula.

85 citations

01 Jan 1966

TL;DR: Synthesis of low-noise feeds for large circular paraboloids using hybrid modes propagated in cylindrical waveguides - antenna field patterns was presented in this article, where

Abstract: Synthesis of low-noise feeds for large circular paraboloids using hybrid modes propagated in cylindrical waveguides - antenna field patterns

7 citations