Wideband Characteristic of Dipole Antenna on Mushroom-like EBG Substrate with Narrow Gap

In this paper, we adopted the EBG structure for the antenna substrate to achieve low profile antennas. The thin mushroom-like EBG substrates with narrow gaps were fabricated to limit the area size of the substrate to apply small equipments. The impedance and radiation pattern of a dipole antenna were measured when the antenna was closely located above the EBG substrate. It was confirmed that a dipole antenna located 80 mum above the EBG substrate worked well through wideband. It has been observed that the EBG substrate with the area similar with the footprint of the antenna is enough to obtain a good VSWR. The verification of the operation mechanism and the application to wireless small terminals are future works.