Showing papers on "Feed horn published in 1971"
Patent•
29 Jul 1971TL;DR: In this article, a base-band transmitter and receiver antenna system for operation in sub-nanosecond pulse radio systems of the type detecting the presence or range of near-by reflecting objects utilizes directive, dispersionless, broad band traveling wave transmission line radiators and antenna elements arranged cooperatively to limit the effect of baseband energy directly coupled from the transmitter to the receiver.
Abstract: A base-band transmitter and receiver antenna system for operation in subnanosecond pulse radio systems of the type detecting the presence or range of near-by reflecting objects utilizes directive, dispersionless, broad band traveling wave transmission line radiator and receiver antenna elements arranged cooperatively to limit the effect of base-band energy directly coupled from the transmitter to the receiver.
50 citations
TL;DR: In this article, the possibilities of an assembly from strips of elliptic shape that are also segments of parabolic dishes are discussed, which can be modified and improved, depending on the type of strip configuration proposed.
Abstract: To produce directional antenna patterns having a shaped beam in one plane such as is required, for instance, in the case of rotating-search radar antennas having a vertical radiation pattern of cosecant-squared shape, doubly curved reflectors are used as a rule. Besides the well-known composition of such reflectors from a stack of strips of parabolic shape, the paper delineates possibilities of an assembly from strips of elliptic shape that are also segments of parabolic dishes. With reflectors assembled in this way certain antenna characteristics such as directivity, sidelobe suppression, etc., can be modified and improved, depending on the type of strip configuration proposed. Experimental results gained with two different reflectors (width 12.5\lambda , height 5.6\lambda ) assembled from strips of elliptic shape are discussed. One of the strip configurations devised turns out particularly favorable for small reflectors.
43 citations
Patent•
21 Sep 1971TL;DR: In this paper, a composite antenna feed subsystem concentrated in a small area at the prime focus of the parabola of a satellite parabolic reflector accomodates a plurality of frequency bands.
Abstract: A composite antenna feed subsystem concentrated in a small area at the prime focus of the parabola of a satellite parabolic reflector accomodates a plurality of frequency bands. The arrays comprising the subsystem are mounted on the top cover of a communication module. A multimode horn is arranged at the center of the subsystem axis which functions at X- and C-band frequencies, and a cross-array consisting of individual elements form the S-band feed, with one arm of the S-band array containing an element mutually shared with the L-band array. Provision is also made for UHF frequencies, and a dipole arrangement for VHF frequencies is arranged around the S-band arms.
14 citations
Patent•
02 Jul 1971
TL;DR: A reflector antenna has a reflector with an offset feed which is partially encompassed by a shroud which may reflect, absorbing, or both, to energy radiated by the feed.
Abstract: A reflector antenna has a reflector with an offset feed. The reflector is partially encompassed by a shroud which may be reflecting, absorbing, or both, to energy radiated by the feed. The shroud is effective to block energy radiated by the feed that would otherwise spill over the edge of the reflector, only along a portion of the edge less than its entirety.
12 citations
Patent•
15 Jan 1971TL;DR: In this article, the combined scan and track antennas are disclosed, in which the track reflector and its feed and the feed to the scan reflector are all fixed with respect to each other in such a way that a line through the center of the spherical feed antenna and the fixed feed point therefor always is perpendicular to a point on the surface of the reflector through which it extends.
Abstract: Combined scan and track antennas are disclosed, each comprising a reflector and a feed thereto in which the track reflector and its feed and the feed to the scan reflector are all fixed with respect to each other and the scan reflector rolls in such a manner that a line through the center of the spherical feed antenna and the fixed feed point therefor always is perpendicular to a point on the surface of the spherical reflector through which it extends.
11 citations
01 Jan 1971
TL;DR: A submitted manuscript is the version of the article upon submission and before peer-review as mentioned in this paper, while a published version is the final layout of the paper including the volume, issue and page numbers.
Abstract: • A submitted manuscript is the version of the article upon submission and before peer-review. There can be important differences between the submitted version and the official published version of record. People interested in the research are advised to contact the author for the final version of the publication, or visit the DOI to the publisher's website. • The final author version and the galley proof are versions of the publication after peer review. • The final published version features the final layout of the paper including the volume, issue and page numbers.
10 citations
TL;DR: In this article, it was shown that the efficiency at any frequency can be estimated from a measured efficiency at another frequency and a carefully calculated design efficiency, in practice, an efficiency measurement at some frequency usually serves to determine the efficiency of all lower frequencies.
Abstract: In recent evaluations of large parabolic reflector antennas, engineers have investigated the antenna performance at several frequencies. In this paper it is shown that the efficiency at any frequency can be estimated from a measured efficiency at another frequency and a carefully calculated design efficiency. In practice, an efficiency measurement at some frequency usually serves to determine the efficiency at all lower frequencies.
9 citations
01 Feb 1971
TL;DR: In this article, a reflector antenna that is corrected for spherical, coma, and chromatic aberrations is described, and experiment on a two-dimensional model has verified the theoretical prediction of its excellent scanning performance over an amazingly wide bandwidth.
Abstract: A reflector antenna that is corrected for spherical, coma, and chromatic aberrations is described. Experiment on a two-dimensional model has verified the theoretical prediction of its excellent scanning performance over an amazingly wide bandwidth.
6 citations
TL;DR: In this article, the features and performance of a 6 GHz transmitter and receiver are described and the system objectives of 41 dBrnc0 for 4000 miles at 1800-circuit loading derived in the previous paper are applied to the design.
Abstract: The features and performance of a 6-GHz transmitter and receiver are described in this paper. The system objectives of 41 dBrnc0 for 4000 miles at 1800-circuit loading derived in the previous paper are applied to the design. With the exception of the 10-watt traveling-wave tube, the equipment is all solid state.
5 citations
TL;DR: In this paper, a set of polarization-transforming antenna feed horns was developed for an X-band radar antenna, which allowed transmission of horizontal, vertical, 45\deg linear, 135\degree linear, right circular or left circular polarization, and reception of both the parallel and orthogonal-polarized return.
Abstract: A set of polarization-transforming antenna feed horns has been developed for an X -band radar antenna. Use of the proper feed horn permits transmission of horizontal, vertical, 45\deg linear, 135\deg linear, right circular or left circular polarization, and reception of both the parallel- (same sense as transmitted) and orthogonal-polarized return.
5 citations
TL;DR: In this article, the received field as focused by the parabolic main reflector of a Cassegrainian antenna at the surface of an arbitrary profile subreflector is calculated by a spherical wave expansion.
Abstract: The received field as focused by the parabolic main reflector of a Cassegrainian antenna at the surface of an arbitrary profile subreflector is calculated by a spherical wave expansion. This facilitates the application of the field correlation principle and leads to an expression for aperture efficiency taking into account diffraction effects. A comparison is made with numerical results previously published or obtained by other methods. The potential advantage of the technique is the speed of computation and the capability for synthesis as well as analysis of reflector shapes.
Patent•
18 Aug 1971
TL;DR: In this paper, the authors describe a two-phase motor with a feed horn and a wormwheel, which can be used with a parabolic dish reflector to produce a fan beam.
Abstract: 1,243,083. Aerials. HOLLANDSE SIGNAALAPPARATEN N.V. 1 Oct., 1968 [4 Oct., 1967], No. 46647/68. Heading H4A. A feed horn 2, Fig. 2, comprises a narrow side wall 7 which is hinged at the throat 1 of the horn, and which is provided with driving means for moving it either to the outside, for producing a large aperture, or towards the centre. With a large aperture the horn radiates a narrow beam, and with a small aperture it radiates a fan beam. A crank which moves between two extreme positions 9, 10, in each of which it is substantially perpendicular to the axis 34 of the throat 1, and is held locked, is coupled by a connecting rod 17 to the wall 7, and is fixed to a shaft 8, which is rotatable in either direction by counter-acting spiral springs. The said springs are so adjusted that were they not constrained the crank would float mid-way between the positions 9, 10. A reversible two-phase motor 15, which is geared to a worm 53 driving a wormwheel 26, Fig. 3, is provided for expanding and contracting the said spiral springs 22, 23. The said worm-wheel rotates freely on the shaft 8 and has on its sides cover-plates 27, 28 forming a spring drum 14 which contains the spiral springs. The outer end of each spring is attached to its cover plate, and its inner end is attached to a respective ring 30, 31, said rings being fixed to the shaft 8. A spring-loaded pin 20 protrudes from the crank and in the extreme positions thereof abuts either against a face of an upper ratchet 36 or against a face of a lower ratchet 37, said ratchets being provided on a shaft 35, and co-operating with spring-loaded pawls 39, 40. A slidable switch member 16 has stops 45, 46 which co-operate with the faces of a central ratchet 38 provided on the shaft 35. In one position of the switch member 16 the crank is locked by the pin 20 engaging the upper ratchet 36, and in the other position of the switch member 16 the crank is locked by the pin 20 engaging the lower ratchet 37. Circuit means for activating the reversible motor may be closed and interrupted by micro-switches that are controlled by the movable side wall 7 and a cam disc provided on the spring drum 14, respectively. The feed horn may be used with a parabolic dish reflector, when a large aperture of said horn provides illumination only of a central area of said reflector, which therefore produces a fan beam. Conversely, a small aperture of said horn provides overall illumination of said reflector, which therefore produces a narrow beam.
TL;DR: In this article, the use of blinders to reduce high sidelobes in the azimuth (transverse) plane radiation for horizontal polarization is discussed, and a half blinder is presented.
Abstract: The use of blinders to reduce certain high sidelobes in the azimuth (transverse) plane radiation for horizontal (transverse) polarization is discussed. A half blinder is presented which reduces objectionable high sidelobes 8 to -62 dB, and maintains low sidelobes elsewhere.
01 Jan 1971
TL;DR: In this paper, a set of polarization-transforming antenna feed horns was developed for an X-band radar antenna, which allowed transmission of horizontal, vertical, 45" linear, 135' linear, right circular or left circular polarization, and reception of both the parallel- (same sense as transmitted) and orthogonal-
Abstract: A set of polarization-transforming antenna feed horns has been developed for an X-band radar antenna. Use of the proper feed horn permits transmission of horizontal, vertical, 45" linear, 135' linear, right circular or left circular polarization, and reception of both the parallel- (same sense as transmitted) and orthogonal-