Metasurface-based Frequency Reconfigurable two-port MIMO Antenna for 5G Application

In this work metasurface based frequency reconfigurable two-port multiple input multiple output (MIMO) antenna is presented. Initially, the proposed antenna is configured as a single-port radiating patch with pin-diode operating in the frequency reconfigurable mode. Later the designed antenna is converted to a two-port MIMO antenna that realizes an S11 below -10 dB intended for two resonant bands operating at 2.95 GHz (2.71-3.33 GHz) and 4.91 GHz (4.48-5.24 GHz) with pin-diode off-mode and 3.69 GHz (2.60-4.79 GHz) in on-mode with maximum peak realized gain of 6.29 dB and 4.13 dB at diode off-mode and 9.84 dB in diode on-mode. The two feeding ports of the proposed antenna are positioned adjacent to each other to permit the antenna in self-isolation mode later metasurface-reflector is placed below 10mm of radiator used as a de-coupling circuit and maintaining the minimum isolation of (S21) below -18.5 dB and maximum isolation of -23.07 dB in off-mode and -20.48 dB in diode on-mode. Moreover, the isolation and peak realized gain has improved after adding a reflector to the proposed antenna. The distance between antenna elements is 0.04 λo. The designed antenna is applicable for 5G new radio (NR) bands of
$n7$
,
$n48$
, n77, and
$n78$
in on-mode, and n79 in diode off-mode respectively.