Metasurface-Inspired Circularly Polarized MIMO Antenna for 5G mmWave Applications

This letter offers metasurface-inspired multiple-input--multiple-output (MIMO) antenna with circular polarization (CP). The antenna radiating element consists of 1 × 2 array nonbianisotropic split ring resonator with an interdigital capacitance. Furthermore, a four-port MIMO antenna is designed with a 8 × 8 metasurface array (M-Array) on the ground plane. The dimensions of the proposed CP MIMO antenna are 4.6<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\lambda _{0}$</tex-math></inline-formula><inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\, \times\, \text{4.6}\lambda _{0}$</tex-math></inline-formula><inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\,\times\, \text{0.128}\lambda _{0}$</tex-math></inline-formula> at 28 GHz. The MIMO antenna with an M-Array offers a frequency range of 30.15% [(23.8 to 32.25) GHz], isolation above 55 dB and an overlapping 3 dB axial ratio bandwidth of 14% from 26.5 GHz to 30.5 GHz with a high gain of 18.5 dBi. The proposed MIMO antenna is simplified into an equivalent circuit model. Diversity metrics ensures good diversity performance including, envelope correlation coefficient (ECC <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$&lt; $</tex-math></inline-formula> 0.01), diversity gain (DG <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\approx$</tex-math></inline-formula> 10 dB), channel capacity loss (CCL <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$&lt; $</tex-math></inline-formula> 0.1 bits/Hz), and total active reflection coefficient (TARC <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$&lt; $</tex-math></inline-formula> –10 dB). The proposed MIMO antenna's operational range includes the mmWave band [(25 to 29.5) GHz]. It is well suited for 5G new radio smart devices due to its better performance and compatibility with 5G communication standards.