ABSTRACT
A quad-port multiple-input multiple-output (MIMO) filtenna with compact dimensions of 50 ×50 mm2 are configured, in which each element is placed orthogonally to its adjacent to enhance the isolation. The MIMO element is configured based on the novel COVID-19 virus shape with a co-planar waveguide feeding structure (CPW) and dimensions 17 ×22 mm2. The element bandwidth is ranging from 3.3 GHz to more than 60 GHz. Three frequency notches are designed at 3.5 GHz for WiMAX and 5.5 GHz for WLAN, and 8.5 GHz for X-band applications. A bandpass filter (BPF) with high out of band rejection is used as a decoupling structure (DS) to improve the isolation to more than 30 dB across most of the bandwidth. The equivalent circuit model is scrutinized to investigate the enactment of the decoupling structure. The proposed MIMO filtenna system provides an impedance bandwidth of 2.4–18 GHz, a peak gain of 13.2 dBi, and an envelope correlation coefficient (ECC) less than 0.00021. In turn, channel capacity loss does not exceed 0.2. The MIMO filtenna is fabricated and measured. Good agreement between the measured and simulation results is achieved. Author