This study presents the investigation on the effect of rectangular slot on resonance frequency, return loss and band widths, gain and directivity of rectangular microstrip patch antenna. The design is achieved by cutting the rectangular slots at the radiating element of the patch antenna; in the other step we loaded the films of ferrite between the substrate and the radiating element of the antenna. Compared to the conventional rectangular patch antenna slot loading antennas give the better performance in resonant frequency, loading of ferrite films give a good return loss, for these reasons we have associated the two techniques simultaneously in the same patch antenna for benefit from its advantages and minimized manufacturing cost.