Quad-Port UWB MIMO antenna based on LPF with vast rejection band

This manuscript introduces orthogonally polarized quad-element multi-input multi-output (MIMO) antenna with improved isolation. The proposed design of a miniaturized volume of 43 × 43 × 1.5 mm3 covers vast impedance bandwidth more than 17.85 GHz commences at 2.15 GHz to more than 20 GHz, corresponding to reflection coefficient below – 10 dB. A quad-port low-pass filter (LPF) with a very wide rejection band and low cutoff frequency is suggested as a decoupling structure to boost the isolation to more than 20 dB across most of the bandwidth. Equivalent circuit model is scrutinized to investigate the enactment of the decoupling-structure. The MIMO antenna performing satisfies UWB requirements of relatively omnidirectional radiation patterns and stable radiation characteristics with an average gain 5 dBi. Envelope correlation coefficient (ECC), diversity gain (DG), channel capacity loss (CCL), and total active reflection coefficient (TARC) are analyzed to show the applicability of the proposed antenna to the short-range communications. Both simulated and fabricated results demonstrate good agreement. © 2021 Elsevier GmbH