In this paper, a comprehensive investigation of a microstrip antenna
performance covered with a dielectric layer has been presented. An aperture
coupled antenna has been designed as a case study. Antenna parameters have
been evaluated with and without the presence of a dielectric layer with different
thickness values. Theoretical performance evaluation of this antenna for different
cases, corresponding to the different dielectric thicknesses, has been assessed
using the method of moment (MoM) based EM simulator IE3D, v.10.06. A large
number of dielectric thickness variations have been modeled, in an attempt to
provide accurate antenna parameters response through this range. Simulation
results show that the antenna resonant frequency is reduced as the dielectric layer
thickness is increased. To maintain the resonant frequency, the antenna
dimensions must be scaled down as a result of the existence of this layer. In
addition, results also show that, as the dielectric layer thickness is increased, the
resulting antenna gain decreases.