Hyd. Yang et al., PHOTONIC BAND-GAP MATERIALS FOR HIGH-GAIN PRINTED-CIRCUIT ANTENNAS, IEEE transactions on antennas and propagation, 45(1), 1997, pp. 185-187
It is found through a vector integral-equation analysis and the recipr
ocity theorem that the gain of a microstrip antenna can be greatly enh
anced with a photonic band-gap (PEG) material Layer either as the subs
trate or the superstrate. The beam angle is found to coincide with tha
t of a leaky-wave mode of a planar-grating structure. This observation
suggests that high gain is due to the excitation of strong Leaky-wave
fields.