Cavity Backed Spiral Antenna

SPRL-A0029

The SPRL-A0029 planar Archimedes spiral antenna is a rugged unit designed for airborne applications. The design uses a planar Archimedes spiral etched on a low-loss PTFE/fibreglass substrate which is mechanically supported on the backing cavity using high-performance absorber. The two arms of the Archimedes spiral are fed by a balanced transmission line which incorporates an impedance transformer to match the spiral impedance to the 50 O input impedance of a Marchand balun. Spiral antennas are circularly polarized and are ideal for receiving linearly polarized waves with arbitrary plane of polarization. NOTE: These antennas can be supplied singly, in pairs and in amplitude/phase tracking sets of up to five antennas. Custom mounting flanges can be provided so that the user can rotate the antennas about their axes to make rotational phase adjustments of the relative phases between the spiral antennas in interferometer applications.