Ultra‐compact 4‐port DR antenna for multi‐input multi‐output standards

Abstract

Here, an ultra-compact Multi-Input-Multi-Output (MIMO) antenna system is presented for Wireless Local Area Network (WLAN) applications. The proposed antenna compactness approach is based on using Cylindrical-Dielectric-Resonator-Antenna (CDRA) symmetry with the help of image theory to achieve the best size reduction of the resonators and maintain the resonance frequency of the original CDRA. The electric/magnetic walls approach is utilized to miniaturize the size by exploring the symmetry and antisymmetry of the resonant mode. First, a CDRA for MIMO system is designed and tested in terms of return loss and radiation efficiency. Then, two configurations of MIMO-Antennas (two and four ports) are examined by using the same substrate size. The 2-port-MIMO antenna is built from two half-CDRs (HCDRs) facing each other. Similarly, four-quarter-CDRs (QCDRs) are created to form a 4-port MIMO antenna system. As a result, a 75% size reduction is achieved (size of 30 × 30 × 7.62 mm3). The measured impedance bandwidth for the 4-port MIMO antenna is 5.4% (5.4-5.7 GHz), with more than 15 dB isolation levels. Proper levels of Envelope Correlation Coefficients (ECCs) are also achieved (1 × 10−2-4 × 10−2), with a channel capacity loss (CCL) of 0.04 bits/S/Hz. The proposed MIMO antennas are suitable for compact wireless communication systems.