Compact UWB MIMO antenna with Fork-shaped stub with vias based coupling current steering (VBCCS) to enhance isolation using CMA

Abstract

This paper has proposed a Fork-shaped stub with Vias Based Coupling Current Steering (VBCCS) to enhance the isolation between 2 × 2 and 4 × 4 ultra-wideband (UWB) MIMO antenna. The proposed antenna is evolved using Characteristic Mode Analysis (CMA) to provide physical insight into the structure. The excitation of multiple characteristics modes facilitates the attainment of the UWB spectrum. The VBCCS with Fork-shaped stub based methodology makes it possible to redirect characteristic current and enhance monopoles isolation. The antenna has an overall size of 20 × 28 mm2, which covers the entire UWB spectrum from 3.01 to 13.5 GHz, keeping the isolation of more than 17 dB. The proposed UWB MIMO antenna presents an almost omnidirectional radiation pattern. Moreover, the diversity performance in terms of envelope correlation coefficient (ECC) < 0.01, and channel capacity loss (CL) < 0.04b/s/Hz is analyzed. The proposed UWB MIMO antenna has a scalable phenomenon, and it can be easily extendable into 4 × 4 without any additional decoupling circuit. It operates from 3.05 to 13.05 GHz frequency band with good antenna characteristics.