Two UWB-MIMO antennas with high isolation using isolation stubs

In this paper, two Ultra-wideband (UWB) multiple-input multiple-output (MIMO) antennas with different isolation structures are proposed. A comb U stub and an inverted-T stub are designed to improve the isolation between two antenna elements. Over the whole ultra-wide bandwidth, the return losses are better than 10 dB, and the isolation between two elements are better than 20 dB. The simulation and measurement results agree with each other very well. The proposed antennas are suitable for some portable UWB MIMO/diversity applications.