Enhanced directivity of ultra-thin metamaterial-based cavity antenna fed by multisource

The design of a multisource metamaterial-based cavity antenna operating at about 9 GHz is presented. A 2 x 2 microstrip patch array acting as the multisource embedded in an ultra-thin (lambda/22) cavity shows a directivity enhancement of 4.2 dB with regard to a monosource fed cavity antenna (23.2 dB instead of 19 dB). Moreover, the sidelobes of the multisource are considerably decreased in the cavity.