Stepped cavity-fed microstrip array antenna

A microstrip patch array antenna of aperture 5/spl lambda//sub o//spl times/5/spl lambda//sub o/ is fed by a stepped rectangular cavity resonator through coupling slots etched on its ground plane. The cavity consists of two parts having different transverse dimensions and the same lengths of about /spl lambda//sub o//2. It is excited by a standard waveguide through a slot on it front-end wall. The antenna is analyzed using the cavity mode method. For a particular antenna design, the near- and far-fields are measured and the results are in good agreement with the antenna analysis.<>