CAVITY FEED TECHNIQUE FOR SLOT-COUPLED MICROSTRIP PATCH ARRAY ANTENNA

Slot-coupled microstrip patch arrays fed by rectangular overmoded cavi ties are described and their radiation characteristics analysed using simplified cavity models both for the illuminating and patch resonant cavities. In particular, 4 x 4 single cavity-fed and 8 x 8 stepped cav ity-fed patch arrays were built and studied. With regard to the radiat ion patterns and directivity the measurements satisfactory agreement w ith the measured relative gain bandwidth ranges from 1.2% to 3.1% depe nding on the antenna configuration. Compared with a similar size micro stripline network-fed patch array the 8 x 8 stepped cavity-fed patch a rray antenna has better efficiency and much lower side lobes.