Performance improvement of small arrays of microstrip antennas on photonic band gap substrates

Patch antennas have some limitations such as restricted bandwidth of operation, low gain and a potential decrease in radiation efficiency due to surface wave losses. In this paper, the ability of a Photonic Band Gap (PBG) substrate to minimize the surface wave effects is analyzed for a high ε _r substrate. Instead of the conventional PBG, a metallodielectric structure is employed. A two element linear array and a four element planar array on the PBG substrate are found to give reduced levels of side lobe radiation, increased directivity and a better front-to-back ratio.