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

Abstract
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 without a CATR, the loads are difficult or impossible to realise. An analysis of the measurement of a 2 m antenna, using a lownoise receiver, shows that the accuracy is better than ±0.1 dB for the loss and ±1% for the beam efficiency.