Integration of millimeter-wave planar antennas with photonic crystal structures

A CPW-fed slot dipole antenna configuration was chosen for this work due to the high level of loss into the substrate from total internal reflection of the propagating wave in the device, particularly when fabricated on silicon. The configuration of the device has one major radiating slot which can be easily aligned with the PBG. The PBG structure was designed using the scaling properties of Maxwell´s equations when applied to photonic crystals, and was fabricated using deep silicon dry etching techniques to create a multiple layer woodpile. Free space transmission measurements of the photonic crystal structure have shown a well defined stop band in three dimensions from 70 GHz to over 110 GHz. From experimental results a standard design method has been achieved which can be used to easily integrate antennas at millimetre wave frequencies with photonic bandgap structures which to this point has not been reported at this frequency. This paper intends to outline the design considerations, along with the full set of experimental results that show the uniform and consistent positive affect the PBG structure has on a radiating antenna.