A cavity backed slot with integrated balun

Abstract

A wideband hemispherical-coverage antenna is described. It is a cavity backed slot radiating element with an integrated microstrip balun. The balun structure provides double-tuning of the slot impedance, yielding a combination with a SWR of 2 or lower and a bandwidth in excess of 24 percent. The slot/balun's structure is simple, has a low profile and easy to construct a conformal antenna or an array. Some measured results are presented.