Conical four-arm sinuous antenna

Image of the Conical four-arm sinuous antenna.

The Four-arm sinuous is a two-port dual-linearly polarised, multi-octave bandwidth antenna which is also physically compact. It is well suited to applications that require instantaneous polarisation diversity. The sinuous antenna provides good broadband characteristics but has the added advantage that it is capable of simultaneously receiving signals of different polarizations in the same aperture with good isolation between the ports.

The Conical sinuous provides unidirectional radiation (as shown below) without the need for a bandwidth limiting cavity backing. The structure is generated by projecting the ouline of a planar sinuous onto a cone.

Typical RHC gain radiation pattern - fmin, f0 and fmax.