Coupling Minimization of Dual-Port Meta-Surface MIMO Antenna With Pin Vias for IoT Technology

This study proposed a single-layer, compact, dual-port meta-surface multiple-input multiple-output (MIMO) antenna for Internet of Things (IoT) applications. Coupling between ports is effectively minimized using pin vias, which connects the meta-surface to the ground plane and functions as an LC resonator circuit to suppress useless frequencies. Here, L and C represent inductance and capacitance, respectively. Additionally, pin vias reduces mutual coupling by mitigating concentrated current distributions on the meta-surface components, achieving high isolation. The simulated results reveal a return loss bandwidth (RLBW) spanning 3.76–7.4 GHz (70% at a center frequency of 5.2 GHz) with isolation (S<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">12</inf>) exceeding 19 dB. Furthermore, the envelope correlation coefficient is below 0.035, and the diversity gain reaches 9.82 dB. The antenna achieves a maximum gain of 5.54 dBi at 4.3 GHz. This demonstrates that the pin vias decoupling technique is highly effective for coupling reduction in meta-surface MIMO antennas.