Dual-Loop Antenna for 4G LTE MIMO Smart Glasses Applications

A dual-loop antenna with massive-input–massive-output (MIMO) operation within the fourth-generation Long Term Evolution (LTE) bands for smart glasses applications is proposed. The 2 × 2 MIMO antenna array is formed by converting the glasses frame into two symmetrical single-loop antenna structures and using the glasses “temple” region as a common ground plane. For each single-loop antenna to excite four resonant modes so that it can yield a desirable −6 dB impedance matching across the desired low band (LB), 824–960 MHz, and high band (HB), 1710–2690 MHz, of LTE operations, a simple matching circuit is loaded into the open section of the loop antenna. Further measurements show good efficiency and isolation across the LB and HB for the dual-loop antenna. Finally, the calculated envelope correlation coefficient and ergodic channel capacity of the 2 × 2 MIMO antenna are also discussed.