Improvement of planar antenna efficiency when integrated with a millimetre-wave photonic crystal

In this work a coplanar waveguide (CPW)-fed slot dipole antenna has been integrated with a three-dimensional woodpile photonic bandgap crystal (PBG) in the W-band regime (67-110 GHz) using silicon. A slot dipole antenna has been designed and tested at 94 GHz which exhibits very poor efficiency and has high levels of loss through the back of the substrate. This integration has shown a large positional dependence of the antenna with respect to the layers of the PBG and has led to the optimisation of a slot dipole antenna on the PBG. This type of integration has shown experimentally that the overall operation of an antenna can be greatly improved due to the reflective properties of the PBG.