Microstrip patch array antenna fed by waveguide endwall coupler

In this paper, we present the 2 by 2 array microstrip patch antenna using a waveguide endwall coupler at 24 GHz. This antenna consists of a waveguide feed and four patches that are excited by the endwall coupler. It has the gain of 10.7 dBi and the bandwidth of 1.3 GHz. And half power beamwidth is 31 degree on the E-plane and 35 degree on the H-plane. Because this transition technique is very simple and easy to fabricate, it can be used for low cost and high volume production for commercial millimeter-wave applications.