Surface wave engineering for beam control in planar millimetre-wave antennas

This paper reviews our recent work on the use of surface wave engineering to enhance the functionality of a type of leaky wave antenna known as the `Bull's eye,' operating in the license free 60 GHz band. The Bull's eye antenna comprises a sub-wavelength aperture surrounded by a planar surface patterned with concentric corrugations. Exploiting well-known coupling relations between surface waves on corrugated surfaces, and free space waves, we can control the angle at which the antenna's beam is directed via engineering the surface corrugations. We have shown via simulation and experiment that the beam can be deflected from the normal (or boresight) in a predictable manner, or split into two beams which themselves can be independently deflected. In this paper we emphasise the degree of control possible over the beam by mixing together different E-plane and H-plane shifts.