Improvement of a $2 \times 2$ Port Super Wideband MIMO Antenna with a Volcano Smoke Ground Plane

The increasing demand for higher data rates and larger bandwidths, while maintaining compatibility with multiple wireless technologies, has driven the development of new Multiple Input Multiple Output (MIMO) antennas as a solution. This paper proposes an improved <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$2 \times 2$</tex> super wideband (SWB) MIMO antenna based on the Volcano Smoke Antenna (VSA) radiator. The design demonstrates the effectiveness of curved ground planes in enhancing bandwidth performance. As a result, the new SWB MIMO antenna with a VSA-ground plane was developed, capable of supporting multiple wireless technologies such as 5G, WiFi, IoT, and various other applications. The proposed antenna achieves measured isolation levels <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$S_{n m}$</tex> below −12.95 dB, a reflection coefficient <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$S_{11} \leq-10 ~\text{dB}$</tex> from 3.42 GHz to 50 GHz, and an average realized gain of 4 dBi across the band, while its physical size was reduced from <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$65 \times 65 ~\text{mm}$</tex> to <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$55 \times 55 ~\text{mm}$</tex>. The antenna was fabricated on FR-4 as the dielectric material.