Broad-band VSWR measurements of a Cassegrain antenna

Broadband VSWR measurements are reported on a small
F
-number Cassegrain antenna. Cyclical variations of VSWR between 1.00 and 1.25 with a 350-MHz frequency interval between unity VSWR values were observed over the 8.5-12.4 GHz frequency range. These variations correspond to a change in the power transmission ratio of 1.231 percent between the unity and 1.25 values of VSWR.