A novel printed dual‐monopole array with antenna selection circuit for adaptive MIMO systems

Antenna selection is an effective method to achieve reconfigurable antenna array for adaptive MIMO systems. In this article, a novel printed dual‐monopole array with antenna selection circuit for adaptive MIMO systems is proposed. By four pin‐diodes embedded in the feeding network, the array can operate as a dual‐antenna array and also work as a single antenna while the other is terminated to a matched lumped resistor. When the array operates as a dual‐antenna array the measured bandwidths cover the UMTS band with acceptable isolation. When it works as a single antenna the measured bandwidth still covers the UMTS band. From the measured radiation patterns, it is obvious that the radiation patterns of the selected monopole change little whether the other monopole is selected or not. Accordingly, the system can achieve antenna selection scheme to adapt to the time‐varying channel conditions.