Mutual Coupling Reduction Using a Protruded Ground Branch Structure in a Compact UWB Owl-Shaped MIMO Antenna

A Mchbal,H Elftouh,A Dkiouak,N Amar Touhami

doi:10.1155/2018/4598527

Abstract

A compact ultra-wideband (UWB) multiple input-multiple output (MIMO) antenna with high isolation is designed for UWB applications. The proposed MIMO antenna consists of two identical monopole antenna elements. To enhance the impedance matching, three slots are formed on the ground plane. The arc structure as well as the semicircle with an open-end slot is employed on the radiating elements the fact which helps to extend the impedance bandwidth of the monopole antenna from 3.1 up to 10.6 GHz, which corresponds to the UWB band. A ground branch decoupling structure is introduced between the two elements to reduce the mutual coupling. Simulation and measurement results show a bandwidth range from 3.1 to 11.12 GHz with |S11_|<−15 dB, |S21_|<−20 dB, and ECC < 0.002.

Highlights

UWB technology has been developed rapidly since FCC assigned a range of 3.1–10.6 GHz for UWB applications in 2002 [1]
multiple input-multiple output (MIMO) technology has caught our attention as it significantly increased channel capacity without any additional power or bandwidth [5, 6]; we have found the mutual coupling between the UWB antenna elements which are very large to get installed on a confined space with the multiple antenna elements
We can say that the most critical point that must be considered while designing a MIMO antenna is to attain a low mutual coupling amid adjacent radiating elements because the MIMO antenna system performance can be strongly affected by the mutual coupling between the MIMO antenna elements, which considerably alter impedance matching, radiation efficiency, and channel capacity [9]

Summary

Introduction

UWB technology has been developed rapidly since FCC assigned a range of 3.1–10.6 GHz for UWB applications in 2002 [1]. MIMO technology has caught our attention as it significantly increased channel capacity without any additional power or bandwidth [5, 6]; we have found the mutual coupling between the UWB antenna elements which are very large to get installed on a confined space with the multiple antenna elements. It means that, if the MIMO antenna elements were placed very close to each other, there would be a strong correlation between their signals and the utility of MIMO would be reduced, so the mutual coupling is inversely proportional to the separation between the antenna elements. We can say that the most critical point that must be considered while designing a MIMO antenna is to attain a low mutual coupling amid adjacent radiating elements because the MIMO antenna system performance can be strongly affected by the mutual coupling between the MIMO antenna elements, which considerably alter impedance matching, radiation efficiency, and channel capacity [9]

Results

Discussion

Conclusion