A technique for measuring the time domain response of a dual reflector antenna

In a dual reflector antenna such as the axisymmetrical cassegrain antenna there are a number of mechanisms by which radiation incident on the antenna reaches the feed. An understanding of these mechanisms is important since they can affect the antenna radiation pattern and cause a ripple in the frequency response. The author describes how, by measuring the frequency response of an antenna and using a Fourier transform to generate the time domain response, the nature and relative levels of these mechanism can be identified