A Dual-Port MIMO Antenna Decoupling by Common and Differential Mode Cancellation With High Isolation

In this letter, a dual-port multiple-input–multiple-output (MIMO) antenna decoupling by common mode (CM) and differential mode (DM) cancellation with high isolation is proposed. The basic structure of the antenna features a large rectangular slot in the center of the circular patch, along with shorting pins and other decoupling structures to achieve high isolation. The shorting pins arranged on the perfect magnetic conductor and the metallic strips passing through the perfect electrical conductor can adjust the impedance matching for CM and DM feeding, fulfilling the basic principles for decoupling by CM and DM cancellation. The measured impedance bandwidth reaches 85 MHz (from 3.49 GHz to 3.575 GHz), while the isolation exceeds 25 dB. Analysis of the radiation patterns shows that pattern diversity is achieved between the dual ports of the antenna. The proposed antenna achieved polarized direction matching while maintaining a lower profile and smaller size, and these characteristics make it more suitable for wearable applications.