Circularly polarised periodic leaky-wave antenna with filtering capability

A planar periodic leaky-wave antenna with filtering capability, circular polarisation, and wideband performance is presented. Seamless beam scanning from backward to forward is provided by self-matching the unit cell of the antenna over a large frequency band from 22 to 28GHz. A wide scanning range of 84 degrees is achieved by using a relatively low-permittivity dielectric material. Filtering capability is embedded in the antenna structure which contributes to the minimisation of the overall circuit size which is aimed in recent millimetre-wave antenna in package systems. The proposed antenna has a circular polarisation with an axial ratio of <2dB at broadside which makes it a good candidate for peer-to-peer and peer-to-multipeer communication systems.