SIMPLE APPROACH TO DETERMINE RESONANT FREQUENCIES OF MICROSTRIP ANTENNAS

A simple approach for accurate determination of the resonant frequenci es of microstrip antennas of regular geometries is developed and prese nted. In this approach, a generalised empirical formula for the comput ation of effective dielectric permittivity is given which takes into a ccount the ratio of the fringing area to the area of the patch. A corr ection to the equivalent side length of an equilateral triangular patc h, previously published, is modified and a new formula is given. A cor rection to the effective dimensions of an elliptical microstrip antenn a is also carried out. Numerical results obtained for the resonant fre quencies of elliptical, circular, rectangular and equilateral-triangul ar microstrip antennas are in good agreement with the available theore tical and experimental results reported by others. The present approac h is more efficient, simpler and more accurate.