Cassegrain antenna

About: Cassegrain antenna is a research topic. Over the lifetime, 3207 publications have been published within this topic receiving 28278 citations.

Integrated waveguide cavity antenna and reflector RF feed

Abstract: An integrated antenna and reflector feed is provided which is structured as a waveguide cavity antenna or array having a curved reflector coupled to a sidewall of the waveguide cavity. A radiation source is situated facing the curved reflector and one or more radiating elements are provided on a top surface of the waveguide cavity. Several curved reflector feeds may be used, operating in the same or different frequencies.

Transient Fields of Parabolic Reflector Antennas

Abstract: Requirements to increase the information content of radar and communication systems result in a band width increase and are a reason to investigate and describe the transient fields from ultra wideband (UWB) large antennas1. Furthermore, a need in such an analysis occurs in near field time domain antenna measurements2. In these cases not only the transient far field is of interest. The spatial-temporal near-field distribution is useful too to the optimal antenna arrangement on the complex objects. Mention must be made that many issues of the theory of an impulse radiating antenna. (IRA) are discussed by Carl E. Baum. Everett G. Fart and D. V. Giri3–8. The transient field from the circular focused aperture with uniform held distributions was considered in3. Much attention is given to IRA which consists of a large angle conical TEM feed that attach to a reflector antenna. It was shown that radiated held includes three distinct pacts. The first of these is the direct radiation from the feed structure (prepulse), whirl is of rather low magnitude, but lasts for a fairly long time This is followed by an impulse, which lasts for a brief time and is high in amplitude. Finally, there is a tail expected after the impulse. Closed-form expressions for prepulse were presented in 4. Analysis was extended to include the diffracted fields from the launcher plates and the circular rim of the reflector5. It was shown that there is an exact time-domain match of the spherical and planar TEM waves (inhomogeneous) at the reflector4–7. Thu exact expressions for the acoustic fields on the z axis for a circular aperture were obtained in 8. While the above-mentioned works describe basic properties of transient fields of an IRA, many questions are yet to be investigated.

Feed assembly for multi-beam antenna with non-circular reflector, and such an assembly that is field-switchable between linear and circular polarization modes

Abstract: A feed assembly for an antenna having a non-circular reflector, in which the feed assembly includes a feed horn capable of correcting the distortions of circularly polarized signals caused by the non-circular reflector profile, and wherein the feed horn is coupled with a polarizer that is field-switchable between linear and circular polarization modes of operation. The feed assembly can include a second receive-only feed located in close proximity to the feed horn for communication with adjacent satellites.

Phase center calculations of reflector antenna feeds

Abstract: A method of determing the optimum phase center location of antenna feeds employed in reflector systems is described. The phase center of the wide-band scalar horn used in prime-focus and dual-reflector antennas has been calculated numerically and the results are discussed.

Generalized classical axially-symmetric dual-reflector antennas

Abstract: Classical axially-symmetric Cassegrain and Gregorian reflectors are widely used in high-gain antenna applications. The main disadvantage of these configurations is the subreflector blockage, which causes a number of deleterious effects. However, this problem can be reduced by decreasing the main-reflector radiation toward the subreflector. This may be accomplished either by shaping both reflectors or by using alternative classical configurations. This work considers the second option by presenting, in an unified way, generalized classical axially-symmetric configurations that prevent, from a geometrical optics (GO) stand point, the main-reflector scattered energy from striking the subreflector surface. Starting from initial design variables, closed-form expressions are derived for the relevant surface parameters, as well as for the corresponding aperture field distributions. These expressions can be used as effective design tools to determine the final antenna geometry or even to establish an initial configuration for a shaping procedure.