An electrically-thin, two-pole, bandpass radome

A two-pole bandpass radome is comprised of an inductive ground plane with symmetric capacitive FSS structures equally spaced on either side. Capacitive patches in these two FSS structures are connected with the ground plane by virtue of plated through holes. Spurious modes are suppressed over a very broad frequency band between the desired passband and the parasitic resonance of the FSS patches, which can be up to an order of magnitude in ratio due to the relatively small size of the patches. Furthermore, the total radome thickness can be designed to be less than /spl lambda//sub 0//50 at the fundamental passband. An L-band example is fabricated and tested.