Impedance Matching of Microstrip Patch Antennas by Using Frequency Selective Surfaces (FSS)

In microstrip patch antennas; increasing the impedance matching between the feed line and antenna increases the reflection efficiency. Impedance matching techniques in the literature have been varied according to antenna geometry and type of feeding. In this study, an impedance matching technique by using frequency selective surfaces (FSS) is proposed for microstrip patch antennas. Firstly, a microstrip patch antenna, called Design 1 is designed at 28 GHz. In order to improve the radiation performance of Design 1, Design 2 is obtained by using the inset-fed impedance matching technique. In the last step, Design 3 has obtained by placing an FSS structure, which is consisted of close ring resonators, on the ground plane of Design 1with the method proposed in this study as an alternative impedance matching technique. The close radiative performances of Design 2 and Design 3 is shown that the impedance matching technique by using FSS can be successfully used instead of the inset-fed impedance matching technique.