A monopole array driven from a rectangular waveguide

The elements of a monopole array can be excited by probe-coupling them to a rectangular waveguide. It is shown theoretically and verified experimentally that there is a monopole height that maximizes the power extracted from the waveguide for a given probe depth. The analysis treated the probe in the waveguide as a receiving antenna connected to the outer monopole by a short length of coaxial line. The relative power radiated was determined from insertion loss measurements at 2840 Mc.