A simple impedance-matching technique for patch antennas fed by coplanar microstrip line

A simple impedance-matching technique for the patch antennas fed by a coplanar microstrip line is presented. By placing a shorting through hole at a proper position, the resonant input resistance of the edge-fed patch antenna can be easily tuned to 50 Ω. For the cases of the patch antennas with the aspect ratios varied from 0.5 to 2, both theoretical and experimental investigations of the proposed technique are carried out. From the obtained results, it is shown that, to acquire the 50 Ω input impedance, the position of the through hole is only related to the length of the radiating edge of the patch antenna. Details of the antenna design are presented.