A Highly Efficient and Low-Mutual Coupling Partial $\pi /8$ SIW Cavity-Based 8-Port MIMO Antenna

Abstract

A sector-shaped compact <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\boldsymbol{\pi}/\mathbf {8}$</tex-math></inline-formula> partial substrate-integrated waveguide cavity antenna from the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\rm {\mathbf{TM}}_{\mathbf{220}}$</tex-math></inline-formula> diagonal mode of the SIW cavity is presented. A 61 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\%$</tex-math></inline-formula> size miniaturization is achieved compared to the SIW rectangular cavity in its complete mode configuration. The compact cavity radiator is used as an element of a compact 8-port multiple-input–multiple-output (MIMO) antenna. The 8-port MIMO antenna occupies the entire full cavity with slots loaded on the top and bottom layers. The fabricated prototype has a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$-$</tex-math></inline-formula> 10 dB impedance bandwidth (BW) from 6.006 to 6.143 GHz. The mutual coupling within the BW is less than <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$-$</tex-math></inline-formula> 21 dB. The presented MIMO antenna has an envelope correlation coefficient (ECC) less than 0.0027, and a percentage diversity gain reduction below 1.73 <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\%$</tex-math></inline-formula> , which makes it a suitable candidate for use in MIMO-based wireless communications.

Topics & Concepts