Dr. Jackson et al., LEAKY-WAVE PROPAGATION AND RADIATION FOR A NARROW-BEAM MULTIPLE-LAYERDIELECTRIC STRUCTURE, IEEE transactions on antennas and propagation, 41(3), 1993, pp. 344-348
Previous work has demonstrated that very narrow beam radiation pattern
s can be obtained from a simple source embedded within multiple dielec
tric layers of appropriate thicknesses above a ground plane. The confi
guration consists of dielectric layers having permittivities epsilon1
and epsilon2 stacked in an alternating arrangement, With epsilon2 > ep
silon1. This narrow-beam effect is attributable to weakly attenuated l
eaky waves that exist on the structure. Employing a new approach, simp
le asymptotic formulas for the propagation and attenuation (leakage) c
onstants are derived which show how the beamwidth varies with the numb
er of layers and the material constants. The exact radiation pattern i
s compared with the leaky-wave pattern for a specific case to demonstr
ate the role of the leaky waves in determining the total pattern.