Improving microstrip patch antenna performance using EBG substrates

Microstrip patch antennas mounted over a high impedance electromagnetic bandgap (EBG) substrate are studied. The structure is equivalent to a new microstrip, antenna, where the conducting ground plane is replaced by a high impedance EBG layer. Initially, the bandgap of the EBG structure is determined, Then, patch antennas with this EBG ground plane are designed to work within and outside the bandgaps. Parametric studies are conducted to maximise their impedance bandwidths and gains. It is found that very wide bandwidths, of around 25%, can be obtained by variation of the original antenna and EBG parameters. Their gains are similarly increased. Sample antennas are also fabricated and tested, to verify the designs.