Integrated cavity-backed ka-band phased array antenna

A planar 4x4 phased array antenna with 0.5 wavelength element spacing at 36 GHz is presented in this paper. The antenna is fabricated by a sequential surface micromachining process with ten structural layers. The radiators are rectangular coaxial line fed cavity backed patches. They are 2.8 mm long and 3.2 mm wide and have two slits for impedance matching and six holes for releasing sacrificial photoresist. The patches are supported with feeding probe and two metallic posts located in a plane of zero electric field. Analysis and design are conducted with finite element and finite integration based codes. The individual antenna elements have impedance bandwidth of about 5.1% around 36 GHz, with simulated gain and radiation efficiency of about 6.8 dBi and 95%, respectively. Computed characteristics of 16 independent, simultaneously available beams are also presented.