HMSIW-Based MIMO Antenna with Enhanced Isolation for Advanced V2X Communication

In this paper, a 2-port Multiple-Input Multiple-Output (MIMO) antenna based on Half-Mode Substrate Integrated Waveguide (HMSIW) is proposed. The antenna consists of modified L-shaped slots on the top metallic plane of the HMSIW structure. The antenna achieved a high port isolation of 35 dB and a significant gain of 4.86 dBi. These performance characteristics are attained with an electrical size of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$0.23\lambda_{0}\times 0.52 \lambda_0$</tex>, where λ<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</inf> represents the free space wavelength at the resonant frequency. Specifically, the antenna operates at 5.57 GHz, corresponding to 5G NR bands n46 and n47, which are well-suited for Vehicle-to-Everything (V2X) communications, meeting the requirements for reliable and high-speed data exchange in V2X applications. Additionally, the MIMO antenna exhibits a mean effective gain (MEG) of -3 dB, diversity Gain (DG) of 9.99 and envelope Correlation Coefficient (ECC) of 0.000071. The proposed HMSIW-based MIMO antenna, with its advantages such as compact size, high isolation, and efficient performance, is particularly suitable for advanced V2X applications.