Abstract

This letter proposes an orthogonal decoupling method for co-frequency MIMO antennas with unbroken metal rim, operating in Wi-Fi 2.4GHz. The decoupling technique just requires two lumped elements between two ports.Two orthogonal surface currents and radiation pattern diversity are obtained. By adding a capacitive and an inductor, with insensitive of matching circuits, it is easy and significant to improve isolation with near 50dB for smart watch antennas. Moreover, forearm causes lower isolated frequency, and has a little effect on impedance matching with the radiation pattern orthogonal to the forearm.