The modified Wolff model (MWM), which is an improved version of the cavity
model, is presented to compute the resonance frequency and input impedance
of a rectangular microstrip patch antenna under the isotropic/anisotropic s
ubstrate-superstrate configuration. The model has accuracy better than 1.5%
for both the resonance frequency and resonant resistance, as compared agai
nst the results of the method of moments (MOM) and experimental results.