A Compact Monopole Array with Increased Port Isolation

Abstract

Strong mutual coupling between closely spaced elements in compact antenna arrays may cause significant system performance degradation. Decoupling networks can be used to compensate for the mutual coupling effect. In this paper, a new compact network structure is proposed to enhance the port isolation between three closely spaced antennas. This 6-port network consists of only a microstrip ring. Transmission lines are used to connect the output ports of the network to the terminals of the three-element array. Open stubs match the input ports of the network to the system impedance. A three-monopole array with the proposed decoupling and matching network was fabricated. The experimental results show that port isolation is achieved for this compact three-monopole array.