QuinStar Technology’s QRC series Cassegrain reflector antennas are available in diameters ranging from 10 inches to 4 feet (25 to 120 cm) for any frequency in the 18-140 GHz range. They operate over a fairly wide frequency range which is limited only by the circular waveguide bandwidth. Gain is determined by antenna diameter, frequency of operation and feed illumination. These antennas are typically more efficient than the prime focus antennas, as the feed line losses are eliminated and a better match is obtained.
The main reflector is parabolic in shape and machined very accurately of either aluminum or a composite material. The subreflector is optimally designed and adjusted for best performance. The subreflector and support structure create minimal blockage and hence produce reasonably low sidelobe levels, generally below 16 dB. The feed horns are selected to produce optimal illumination for low side-lobes and high gain. The interface to these antennas is a circular waveguide of suitable diameter for the center frequency. However, an integral circular-to-rectangular waveguide transition is available as well as a variety of other options, including a detachable circular-to¬-rectangular transition, orthomode transducer (OMT), circular polarizer (fixed or adjustable) and mountable bore-sighted telescope.
QuinStar’s series QRC Cassegrain reflector antennas are ideally suited for applications requiring relatively low depth and good input match. However, Cassegrain antennas of diameters smaller than 10 inches (25 cm) are not recommended, particularly for frequencies below 30 GHz.