Analysis of a Proximity Coupled Patch Antenna on a Metalized Substrate

This paper investigates the periodic metallic loading effects on a proximity coupled microstrip patch antenna fed by a microstrip line. Specifically a mushroom-type EBG structure is investigated. When the loading elements are small and capacitive, metallic loadings have the effect of reducing patch antenna size with the same center frequency with a slight decrease in bandwidth. When the EBG structure is sufficiently large and resonates at a similar frequency as the patch antenna, the high-impedance surface effect is not seen and the bandwidth actually decreases. This result is due to the similar dimensions of patch antenna and the loading elements