Proposed method for measurement of absorption loss and beam efficiency of large MM-wave reflector antennas in compact antenna test range by using hot and cold loads

A novel method to measure absorption loss and beam efficiency of large reflector antennas at millimetre wave frequencies is presented. It is based on a compact antenna test range (CATR) which has hot and cold loads placed at the focal plane. The size of loads is feasible. If the measurements are carried out with a CATR, the loads are difficult or impossible to realise. An analysis of the measurement of a 2 m antenna, using a low-noise receiver, shows that the accuracy is better than +or-0.1 dB for the loss and +or-1% for the beam efficiency.