Effect of window size and its location on resonant frequencies of a rectangular microstrip antenna

The effects of introducing window(s) on the metal patch of a rectangular microstrip patch, on the resonant frequencies of the two modes are investigated. The change in the resonant frequencies with variation in dimensions of the metal patch are also studied.. The results are useful for similar studies on other antenna structures for multiband behaviour useful in mobile communication. The results form the basis for realizing the resonant frequency values of a microstrip antenna of any geometrical configuration.