Enhanced patch-antenna performance by suppressing surface waves using photonic-bandgap substrates

The microstrip patch antenna is a low-profile robust planar structure. A wi de range of radiation patterns can be achieved with this type of antenna an d, due to the ease of manufacture, is inexpensive compared with other types of antennas. However, patch-antenna designs have some limitations such as restricted bandwidth of operation, low gain, and a potential decrease in ra diation efficiency due to surface-wave losses. In this paper, a photonic-ba ndgap (PBG) substrate for patch antennas is proposed, which minimizes the s urface-wave effects. In order to verify the performance of this kind of sub strate, a configuration with a thick substrate is analyzed. The PBG patch a ntenna shows significantly reduced levels of surface modes compared to conv entional patch antennas, thus improving the gain and far-field radiation pa ttern.