Microwave delay characteristics of Cassegrainian antennas

A technique is presented in which the time an RF signal is delayed in propagating through a Cassegrain antenna is determined. The technique utilizes the group delay time and the envelope delay time as found from the antenna transfer function. The calculations show that a focused antenna is basically a nondispersive device whose delay time may be found from an optics formula. Small subreflector displacements result in significant delay changes requiring calibrations for many applications.