A compact planar MIMO monopole antenna with reduced mutual coupling for WLAN applications using ELC resonator

This paper presents a novel mutual coupling reduction technique of compact two-element multiple-input multiple-output (MIMO) antenna using Electric-LC (ELC) resonator. The proposed antenna has omnidirectional radiation pattern and the 20 dB isolation bandwidth is 9.8 %, i.e., from 5.31– 5.86 GHz which covers the WLAN frequency range of IEEE 802.11a standard whereas return loss of the proposed antenna is better than 15 dB throughout the entire band. The separation between antenna elements is only 0.14λ0, where λ0 corresponds to free space wavelength at 5.7 GHz. The radiation pattern is negligibly affected and the proposed antenna has 8.5 dB lower mutual coupling than that of the reference antenna due to the ELC resonator. This concept is verified with fabrication and measurement.