Compact microstrip antenna loaded with T-shaped slots

A compact circular microstrip antenna loaded with T-shaped slot is presented. The same antenna is then enclosed in a metallic cavity to achieve further compactness. A 50% compactness is achieved using cavity backed configuration when compared with conventional circular microstrip antenna. Alternatively, miniaturization is also achieved by employing symmetry with respect to the feed-axis and using only half of the antenna configuration. The effect of notch and slot length on the resonant frequency is also investigated and observed that the resonant frequency of the antenna can be varied simply by varying either the notch length or the slot length.