Isolation improvement method for mobile terminal antennas at lower UHF band

A novel method to improve the isolation between antenna elements on a mobile terminal at the 900-MHz frequency band is introduced. The characteristics of dual-antenna systems have been studied by simulations. The purpose is to use a combination of balanced and unbalanced antenna structures. In addition, the diversity performance in three different radio propagation environments is investigated. It is shown that the proposed structures can achieve up to 100 dB port-to-port isolation and the effective diversity gain of 10 dB in an urban propagation environment.