The QSP-RC-18-42-K-SG is a right hand circularly polarised spiral antenna that operates from 18 GHz to 42 GHz. This cavity-backed spiral antenna has a gain from 1 to 4.2 dBiC with a VSWR of less than 2:5:1. has an axial ratio of less than 2 dB and a diameter of 35.4 mm and is 45 mm long. It is ideally suited for airborne and ground based applications and Spectrum Management Direction Finding 360 antenna arrays. Steatite also provides custom designed spiral antennas.