Multi-physics design and performance of a surface- micromachined Ka-band cavity backed patch antenna

A rectangular coaxial line fed cavity backed patch antenna element for a Ka-band phased array at 36 GHz is presented in this paper. The antenna is fabricated by a sequential microfabrication surface micromachining process with ten structural layers. The patch is 2.8 mm long and 3.2 mm wide and has two slits for impedance matching and six holes for releasing the sacrificial photoresist. It is supported with the feeding probe and two metallic posts located in the plane with zero E-field. The electromagnetic-thermal-stress analysis and design are conducted with the finite element and finite integration codes. 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.