# Wideband Terminal Antenna System Based on Babinet’s Principle for Sub-6 GHz and Wi-Fi 6E/7 Applications

## TL;DR

This paper introduces a new method to design wideband antennas for 5G and Wi-Fi 6E/7 using Babinet’s principle, achieving high performance and efficiency.

## Contribution

A novel input impedance analysis methodology based on Babinet’s principle is proposed to enhance antenna bandwidth.

## Key findings

- Combining open-slot and planar monopole antennas in parallel significantly improves bandwidth.
- The designed MIMO system achieves better than 12 dB isolation and over 45% total efficiency.
- The methodology is validated through MATLAB simulations and equivalent circuit analysis.

## Abstract

In this paper, a novel input impedance analysis methodology based on Babinet’s principle to broaden bandwidth is proposed, and a broadband multiple-input and multiple-output (MIMO) antenna system is designed, fabricated, and measured for fifth-generation (5G) and Wireless Fidelity (Wi-Fi) 6E/7 mobile applications. By analyzing the input impedance of open-slot antennas and planar monopole antennas using numerical calculations, the characteristics of the input impedance can be obtained. We find that combining the two antenna types in parallel can significantly enhance the bandwidth. Then, the four-dimensional image calculated by MATLAB based on the parallel impedance formula is processed to validate the methodology. Thus, a broad antenna element based on the impedance property analysis methodology is achieved, which operates ranging from 2.6 GHz to 7.46 GHz. Moreover, the equivalent circuit of the antenna element is established to further verify the validity of the methodology. Finally, a broadband MIMO antenna system consisting of eight antenna elements is designed, fabricated, and measured, and the isolation performance is better than 12 dB. Acceptable total efficiency higher than 45% is also obtained with envelope correlation coefficients (ECCs) lower than 0.05. The proposed impedance property analysis methodology innovatively proposes a new way to increase bandwidth, which can be widely applied in various antenna designs. Also, reasonable results show that the proposed MIMO antenna system is a good candidate for 5G and Wi-Fi 6E/7 mobile applications.