Polarisation-dependent electromagnetic bandgap incorporating a slanted sheet via

This study describes a novel sheet via polarisation-dependent electromagnetic bandgap surface. The properties of the surface are shown to vary with the via angle and length selected. The former adjustment causes asymmetric behaviour to linear incident waves and the latter brings about a reduction in inductance and consequent increase in resonant frequency. A 45° inclined via is examined in terms of its response to linear and circularly polarised (CP) waves. It is shown via simulation that linear polarised plane waves can be converted to CP with an axial ratio better than 0.4 dB. The study also demonstrates that at the centre of the design band the surface reflects co-handed waves in response to CP incident waves. Finally, the study details a dual-band CP antenna with a single port, achieved by exciting the surface with a bazooka-balun dipole.