Showing papers on "Feed horn published in 1986"

Hybrid mode feed horn having funnel-shaped horn flange with grooved conical inner surface

Abstract: A hybrid-mode feed horn for feeding a reflector from the primary focus has a flange provided with grooves in an inner funnel-shaped surface thereof. The horn flange is formed to enable illumination of deep reflectors with a high aperture efficiency, low spill-over and high sidelobe suppression. The half opening angle θo of the horn flange (7) is specified in the region 70°<θo<80°. An offset of the feeding waveguide (3) in relation to the horn throat plane (21) is adjustable.

The strip-loaded hybrid-mode feed horn

Abstract: A novel typed of hybrid-mode feed horn is presented. It comprises a hollow conical dielectric waveguide whose outer surface is metallized, and whose inner surface is coated with circumferentially oriented conducting strips. It may be designed to have mimimal cross polarization at two arbitrarily separated frequencies, as for a dual depth corrugated horn. Compared to the corrugated horn, it has the potential of lower weight and lower price. Small horns will have some cross polarization due to undesired radiation from the fields transmitted within the dielectric.

Dual frequency feed satellite antenna horn

Abstract: A feed horn arrangement for reception of C-band and Ku-band signals by a single satellite antenna. The arrangement permits a Ku-band feed horn and amplifier to be mounted at the focus of a satellite dish in addition to the C-band reception equipment. A dielectric rod is mounted within the preexisting C-band waveguide to act as a waveguide to direct Ku-band signals to the Ku-band feed horn and amplifier. The Ku-band dielectric waveguide has no effect on the C-band signals which are amplified by the standard C-band amplifier. The dielectric waveguide may be either straight or curved according to the configuration of the C-band reception equipment.

Satellite receiver and acquisiton system

Abstract: The invention provides a master controller to store and call up on command a plurality of setups for numerous satellites. An antenna is directed to a desired satellite, the polarization of the feed horn is changed to that of the signal to be received and a receiver or receivers are switched to the proper band, C or Ku. A transponder is selected as are audio and/or video frequencies, half or full transponder modes in the Ku band, and video reverse. The setup is recalled by an operator or by a timer which can call or set up at prescribed periodic intervals or on a one-time basis. An operator can change one or more parameters of a specific setup. The controller can institute an antenna search routine for developing a new setup to maximize the signal strength by looking at a narrow band AGC signal whereby to permit an operator to acquire a new satellite and store all of the necessary parameters for the setup or to use a frequency controller of the receiver to define the audio and video frequencies to be employed while using the antenna control to acquire the satellite and peak the signals and then store a setup from the information generated by the two controlling elements.

Three Facility Low-Noise Receivers for Millimeter and Submillimeter Radio-Astronomy

Abstract: Receivers are reported for the frequency bands 40-50 GHz, 215-245 GHz and 460-490 GHz. All use Schottky barrier diode mixers, cooled to 15 K, in a waveguide construction. In the two upper frequency ranges, a lens is required to match the telescope to the feed horn. Antenna and astronomical results on the first two receivers are reported.

Reflector antennas for electron cyclotron resonance heating of fusion plasma

Abstract: For electron cyclotron resonance heating (ECH) of fusion plasma, transformation is required of the millimeter wave output from a gyrotron, circular TE/sub 0n/ mode, into a linearly polarized wave beam. It is easily realized by use of a parabolic cylinder reflector. Vlasov et al. proposed this type of reflector antenna which has a stair-cut aperture at an end of a circular waveguide. The authors recently proposed another type of antenna that also uses a parabolic cylinder and has an obliquely cut aperture. In this paper, the transformation efficiencies of polarization and radiation fields of the two types of antennas are calculated by means of geometrical optics and the Kirchhoff-Huygens principle. Then the authors propose a mode converter, in which the output of this type of parabolic reflector is led to a rectangular waveguide and transformed into TE/sub 10/ mode. In addition, another reflector antenna is proposed that focuses the wave beam using an elliptic cylinder reflector and a parabolic one.

Method for designing sector beam antennas

Abstract: An improved method for designing sector beam antennas. The method is used to provide a sector beam antenna having a feed horn with a cross sectional azimuth dimension and a cross sectional elevational dimension which are optimized to irradiate a reflector to transmit a signal over a coverage area such that the gain-area-product of the transmitted signal is maximized.

Shaped beam reflector antenna

Abstract: A shaped beam antenna of the type comprising a main reflector and a feed horn for irradiating an electromagnetic wave upon said main reflector, the main reflector including, in sectional planes inclusive of a Y-Z plane and planes parallel thereto, a central section and horizontal side end sections adjoining the central section, where Cartesian coordinates are assumed having an origin near the feed horn, a Z-axis extending in a direction of the horizontal center axis of the feed horn, and X- and Y-axes extending in planes perpendicular to the Z-axis. The central section has a plurality of torus reflector segments and each of the side end sections has a plurality of parabolic reflector segments, and the torus and parabolic reflector segments are grouped into first and second portions, the first portion having the reflector segments which are symmetrical with respect to the Y-Z plane, the second portion having first and second sub-portions, the reflector segments of the first sub-portion and those of the second sub-portion being asymmetrical with respect to the Y-Z plane, whereby the maximum radiation direction of the beam reflected from the first portion lies in the Y-Z plane, and the maximum radiation direction of the beam reflected from the second portion lies in planes other than the Y-Z plane.

Multi-direction over the horizon radio communication system

Abstract: PURPOSE:To decrease the number of parabolic antennas which are installed in a communication base station, to 1-2 sets, by constituting a multi-direction communication by using a parabolic antenna of a multi-beam type having plural directivities, or a wide directivity single beam having a wide directional pattern. CONSTITUTION:3 sets of transmitting and receiving devices corresponding to the other stations B, C and D, and one set of multi-beam type parabolic antenna 7 having three pieces of feed horns H1-H3 are placed in a communication base station A. As for the antenna 7, in case when a bearing of the station C and the station D seen from the station A is shifted by K1 degrees, the feed horn H1 corresponding to the station D is set by shifting it from a focus by a focal deviation E1 corresponding to the K1 degrees of the bearing. In this way, by setting the feed horn position in each separate direction, the antenna of the communication base station A has three directivities being independent, respectively, in the directions of the station B, the station C and the station D, by only one set.

A Dual Reflector High Gain Microwave Omnidirectional Antenna

Abstract: The design of a reflector system consisting of conic section reflectors rotated about an axis and fed using a biconical horn is outlined. Shaping of the main reflector to meet a required elevation radiation pattern is then described and some theoretical predictions of performance presented.

Generation of arbitrary elliptic beams using dual parabolic reflector antennas

Abstract: However, previous analyses have considered only certain special geometries of these antennas with a limitation on the ellipticity of their radiation patterns. In this mrk, we show that dual cylindrical parabolic reflectors can be designed to yield any arbitrary ellipticity, which is defined to be the ratio of the beamwidths in the principal planes. The only limitation affecting the beam elllipticity is the practical geometry of the antenna in a

The RF Absorber Horn Test System

Abstract: The RF Absorber Horn Test System The RF Absorber Horn Test System facilitates the measurement of high performance RF anechoic chamber absorbers over the 100 MHz to 18 GHz frequency range. Absorber reflectivity measurements as low as -50 dB are possible at normal incidence with practical sized samples. The test system consists of a square horn lined with high loss wedge absorber driven by a tapered horn section lined with flat high loss absorber. The ta­ pered section is fed by an electrically small source antenna and the square section houses a directional probe antenna which is moved longitudinally along the axis of the horn to detect the standing wave created by the electromagnetic wave reflecting from the test sam­ ple mounted in the end of the square horn and the uniform incident wave formed by the tapered horn at the source end. The measurement system and how it functions are detailed, and examples of measured and reduced data are given.

Cassegrain antenna for TVRO application.

Abstract: An antenna is of the Cassegrain type with a main reflector, subreflector and horn, all circularly symmetric. The horn is corrugated and profiled with the near field focal point of the feed deep within the horn. The main reflector and subreflector are shaped in accordance with the horn pattern to optimize the energy distribution over the aperture of the main reflector. The subreflector, horn, and superstructure of the main reflector may all be of plastic molded construction.

A dual reflector antenna

Abstract: A dual-reflector antenna has an annular shielding device 9 positioned between the feed horn 8 and sub-reflector 10 to reduce spillover. A main reflector 1 is provided. The arrangement is more fully described in G.B. Application 2154067A.

Four-port network coupling arrangement for microwave antennas employing monopulse follow-up

Abstract: A four-port network which is connected to a microwave antenna feed horn for separating four signal paths associated, in pairs, with two polarizations and two frequency bands, and with the network also being utilized for the derivation of antenna tracking signals according to the monopulse principle. A conductor is disposed along the longitudinal axis of the waveguide connecting the antenna feed horn with the four-port network, with this conductor extending, on the one hand, to the region of the antenna feed horn throat and, on the other hand, into the four-port network so as to couple in signals of a higher order mode for the derivation of the antenna deviation signals.

Design procedure for a pencil beam antenna using dual parabolic cylindrical reflectors

Abstract: A design procedure for pencil beam antennas using dual parabolic cylindrical reflectors is presented. Initially, the aperture length is determined according to the required beamwidths, and the reflector focal lengths are selected to yield the desirable beam ellipticity. The angle between the reflectors Is then optimized to minimize the cross-polarization level. The expressions necessary for determination of the reflector geometries, using the selected reflector focal lengths and the angle between them, are also provided. For this design procedure, the feed is assumed to be located on the main reflector or its extension.