Compact Coradiator MIMO Antenna for Super Wideband Applications

Abstract

This article presents a compact planar circular monopole antenna with a shared radiator for super wideband (SWB) applications compatible with multiple-input multiple-output (MIMO) configurations. The novelty lies in the coradiator being a simple circular structure enhanced with stepped impedance feed. The antenna uses a partial ground with a stepped system designed over an RO3003 substrate, with an overall dimension of 29 $\times$ 29 $\times$ 0.8 mm $^3$ . The antenna operates over a wideband from 4 to 50 GHz and beyond. The system works in dual polarization with a shared radiator and offers a peak gain value of 7.15 dBi with a high efficiency of 80%–97%. The proposed antenna provides stunning isolation between the dual orthogonal ports of the shared radiator. The diversity performance of the antenna in terms of envelope correlation coefficient (ECC $<$ 0.002), multiplexing efficiency (ME $=$ $-$ 3.111 dB), diversity gain (DG $>$ 9.995 dB), and mean effective gain (MEG $=$ $-$ 3.01 dB) are also studied and analyzed. The designed structure is fabricated, and antenna parameters are measured. The proposed design meets the desired values, and measured parameters agree with the simulated ones, rendering the antenna a suitable candidate for SWB-MIMO applications. Combining the two standards would help breakthrough in wireless communication. With its wide bandwidth, the proposed design finds scope in Internet of Things (IoT), future 5G, and emerging 6G technologies.