Design of tri-reflector Compact Antenna Test Range for millimetre/sub-millimetre wave and THz antenna measurement
The Compact Antenna Test Range (CATR), which generates a pseudo-plane wave in a very short distance, is commonly employed to measure electrically large aperture antennas for the applications in space remote sensing and radio astronomy. With the increasing operating frequencies, the design of a CATR becomes a technical challenge. This paper presents the designs of two tri-reflector CATRs operating at 200 GHz: a Cassegrain-Gregorian (CG) configuration and a Double Gregorian (DG) one, through a dynamic ray-tracing approach. Both of the designs utilise two shaped sub-reflectors and a spherical main reflector. The characteristics of the two designs were also verified by using a commercial Physical Optics package, GRASP version 9.