Topic
Cassegrain antenna
About: Cassegrain antenna is a research topic. Over the lifetime, 3207 publications have been published within this topic receiving 28278 citations.
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17 Oct 2011
TL;DR: In this paper, a quad-ridge horn antenna is used as a feed for a reflector antenna for radio astronomy applications, which uses elliptically shaped sidewalls to limit the variation of beamwidth over a wide frequency range and to obtain greater radiation pattern rotational symmetry.
Abstract: We present a quad-ridge horn antenna as a feed for a reflector antenna for use in radio astronomy applications. The antenna uses elliptically shaped sidewalls to limit the variation of beamwidth over a wide frequency range and to obtain greater radiation pattern rotational symmetry. The antenna is dual-polarized and matched over more than a 4:1 bandwidth. A design procedure is presented and a prototype designed according to this procedure is shown. Measured and simulated results of the prototype agree with each other well. The antenna is analyzed with a prime focus reflector to determine the range of efficiencies that can be expected.
38 citations
Patent•
23 May 1991
TL;DR: In this article, a fixed-feed dual reflector scanning antenna system with low moment of inertia (MOVI) was described, where the main antenna reflector is intersected by a subreflector longitudinal axis Ls at a rotation point proximate a vertex 20 of the sub-reflector 12.
Abstract: A fixed feed dual reflector scanning antenna system 10 having a low moment of inertia is disclosed herein. The inventive dual reflector antenna system 10 includes an antenna feed structure 16 for emitting electromagnetic radiation. The antenna system 10 further includes a subreflector 12 for redirecting the emitted radiation. The subreflector 12 is intersected by a subreflector longitudinal axis Ls at a rotation point proximate a vertex 20 of the subreflector 12. A main antenna reflector 14 circumscribing a main longitudinal axis Lm projects radiation redirected by the subreflector 12 as an antenna beam. A mechanical arrangement 22 rotates the subreflector 12 about the rotation point so as to vary the angular orientation between the subreflector longitudinal axis Ls and the main longitudinal axis Lm. In this manner the antenna beam is scanned relative to the main longitudinal axis Lm.
38 citations
TL;DR: In this paper, a compact Ka-band monopulse Cassegrain antenna based on the reflectarray elements is presented, which consists of a main-reflectarray, a sub-reflect array, a substrate integrated waveguide comparator, and a monopulse feed to achieve good sum-difference characteristics.
Abstract: A compact Ka-band monopulse Cassegrain antenna based on the reflectarray elements is presented in this letter. The proposed antenna consists of a main-reflectarray, a subreflectarray, a substrate integrated waveguide comparator, and a monopulse feed to achieve good sum–difference characteristics. Compared with traditional monopulse Cassegrain antenna, the total length of the proposed antenna is shrunken to 67.85%. The results of measurement agree with that of simulation very well. The measured SUM beam gain of the proposed antenna is 29.4 dBi by eliminating the loss of Ka-band comparator, the 3 dB beamwidth is 3.85°, the first sidelobe level is under −12 dB, the cross-polarization level is better than −20 dB, and the gain ratios between the SUM and DIFF are about 3 and 5 dB in azimuth and elevation plane, respectively. The measured results show that the proposed antenna is a good candidate for the low-cost multimode tracking system with limited space, especially for that working at high frequency.
38 citations
Patent•
03 Feb 2005
TL;DR: In this paper, a device, system and method integrating forward and panoramic fields is described, which consists of a primary reflector, comprising a convex surface in relation to the forward field, reflective on at least part of the convex surfaces, a secondary reflector forward of the primary reflectors relative to the front field, reflecting on a surface of the surface facing rearward toward the primary reflecting surface, and a primary mirror hole in the primary mirror, substantially centered about an optical axis.
Abstract: A device, system and method integrating forward and panoramic fields is disclosed, comprising: a primary reflector, comprising a convex surface in relation to the forward field, reflective on at least part of the convex surface; a secondary reflector, forward of the primary reflector relative to the forward field, reflective on at least part a surface thereof facing rearward toward the primary reflector; a primary reflector hole in the primary reflector, substantially centered about an optical axis of the apparatus; and a secondary reflector hole in the secondary reflector, substantially centered about the optical axis.
37 citations
TL;DR: In this article, a 15 meter diameter Hoop-Column antenna was analyzed and tested to study shape adjustment of the reflector surface, which consisted of finite element and least squares error analyses to minimize the surface distortions.
Abstract: A 15 meter diameter Hoop-Column antenna has been analyzed and tested to study shape adjustment of the reflector surface. The Hoop-Column antenna concept employs pretensioned cables and mesh to produce a paraboloidal reflector surface. Fabrication errors and thermal distortions may significantly reduce surface accuracy and consequently degrade electromagnetic performance. Thus, the ability to adjust the surface shape is desirable. The shape adjustment algorithm consisted of finite element and least squares error analyses to minimize the surface distortions. Experimental results verified the analysis. Application of the procedure resulted in a reduction of surface error by 38 percent. Quasi-static shape adjustment has the potential for on-orbit compensation for a variety of surface shape distortions.
37 citations