Broadband Decoupling and Matching of a Superdirective Two-Port Antenna Array

Decoupling and matching networks may be used to improve the performance of compact antenna arrays where mutual radiator coupling has caused a degradation of the diversity capabilities. A popular network consists of a 180 degrees rat-race directional coupler, which decouples the antenna ports, followed by impedance matching networks at each port. Researchers, however, usually neglect the presence of losses both within the antenna array and the decoupling and matching network. For this reason, we have built various narrowband and broadband matching networks and compare their performances with the help of calibrated far-field measurement data.