Metamaterial Based Design of Compact UWB/MIMO Monopoles Antenna with Characteristic Mode Analysis

Adamu Halilu Jabire,Sani Saminu,Adnan Ghaffar,Xue Jun Li,Anas Abdu,Mohammad Alibakhshikenari,Ernesto Limiti,Francisco Falcone

doi:10.3390/app11041542

Abstract

In this article, a novel metamaterial inspired UWB/multiple-input-multiple-output (MIMO) antenna is presented. The proposed antenna consists of a circular metallic part which formed the patch and a partial ground plane. Metamaterial structure is loaded at the top side of the patches for bandwidth improvement and mutual coupling reduction. The proposed antenna provides UWB mode of operation from 2.6–12 GHz. The characteristic mode theory is applied to examine each physical mode of the antenna aperture and access its many physical parameters without exciting the antenna. Mode 2 was the dominant mode among the three modes used. Considering the almost inevitable presence of mutual coupling effects within compact multiport antennas, we developed an additional decoupling technique in the form of perturbed stubs, which leads to a mutual coupling reduction of less than 20 dB. Finally, different performance parameters of the system, such as envelope correlation coefficient (ECC), channel capacity loss (CCL), diversity gain, total active reflection coefficient (TARC), mean effective gain (MEG), surface current, and radiation pattern, are presented. A prototype antenna is fabricated and measured for validation.

Highlights

The multiple input multiple output system is all about the channel capacity, and it depends on bandwidth and signal to noise ratio
Many factors could undermine the system performance, especially in compact devices, because of many constraints imposed on MIMO antenna design due to some limitation in terms of area and electromagnetic interaction between the MIMO elements termed as mutual coupling
We use metamaterial in the form of a rectangular loop resonator and a slotted stub for mutual coupling reduction; we look at MIMO antenna design from a modal perspective, that is, using the characteristic mode theory to get a physical insight regarding antenna operating principle without a particular feeding considered

Summary

Introduction

The multiple input multiple output system is all about the channel capacity, and it depends on bandwidth and signal to noise ratio. To have a better performance, some have sought to allocate the operable spectrum dynamically, called spectrum collaboration [4], or increase the operable scope by operating at a millimeter frequency range proposed for a future fifth-generation (5G) [5]. Examples of these technologies are multiple-inputmultiple-output (MIMO) methods [6,7] and full-duplex radio [8]. Each MIMO element’s impedance matching and radiation pattern are assigned based on the presence of other components [12] This electromagnetic interaction between the antenna elements subverts the performance of the MIMO system. It is clearly shown that MIMO radiating elements should have more than one port, and it is desirable to have those ports being isolated and well-paired (for the fact that no matching network is connected)

Methods

Results

Conclusion