Circularly polarized three-element MIMO antenna with diversity and polarization reconfigurability techniques

Abstract

This paper proposes a circularly polarized (CP) three-element multiple-input multiple-output (MIMO) antenna system with diversity and polarization reconfigurability techniques for wireless local-area network (WLAN) applications. The proposed MIMO antenna system employs two CP antennas with endfire characteristics and a broadside slot antenna. The polarization reconfigurability technique is achieved using pin diodes in all three antenna elements. Additionally, the three antennas have distinct directional radiation patterns, improving the MIMO antenna system's diversity performance. The three-element MIMO antenna system is fabricated for validation, and antenna parameters are measured. For all the states, the proposed antenna provides good antenna characteristics for the WLAN frequency band (5.15 GHz − 5.35 GHz). The three-element MIMO antenna exhibits good port-to-port isolation, and MIMO parameters like total active reflection coefficient (TARC), channel capacity loss (CCL), envelope correlation coefficient (ECC) and diversity gain (DG) are within the acceptable range.