Experimental study of a microstrip-probe feed for U-slot patch array antennas

We propose a new type of feeding method for the two-element array of U-slot rectangular patches. We combine the microstrip line and the probe to form a microstrip-probe feed. As confirmed by our experimental measurements, by placing the feeder between the patch and the ground plane, we improved the matching and the front to back ratio (F/B) characteristic over a wide bandwidth, compared to the conventional coaxial-probe feeding method used by Lee (Electron. Lett., vol.31, no.5, p.819-420, 1996).