Decoupling network for a 2-element quasi-Yagi antenna array

An element spacing of less than 1/2 wavelength introduces strong mutual coupling and power mismatch between the ports of antenna arrays. The strong coupling may cause severe degradation on system performance. In order to overcome this problem, an alternative approach to port decoupling is proposed in this paper, the decoupled external ports of the feed network can then be matched independently by using open stub transmission line. To validate this method, a 2-element quasi-Yagi antenna array and a ring hybrid that acts as decoupled network are designed. The results show that this method can decrease the coupling effect and improve the performance of antenna.