3-D-Printed Wideband Circularly Polarized MIMO Dielectric Resonator Antenna

A 3-D-printed wideband circularly polarized (CP) multiple-input–multiple-output (MIMO) antenna is proposed. This antenna consists of two CP dielectric resonator antennas (DRAs) which are covered by a dielectric decoupler. With this decoupler, the center-to-center distance between the two DRAs can be made as small as
$0.33\lambda _{0}$
with a high isolation, where
$\lambda _{0}$
is the operating wavelength in air. To verify the simulation, a prototype operating in X-band was designed, fabricated, and measured. Its measured −10-dB impedance bandwidth is 21.7% (8.88–11.04 GHz), within which the axial-ratio (AR) bandwidth and mutual coupling are less than 3 and −21.4 dB, respectively. The impedance and AR have a wide overlapping bandwidth of 21.7%.