Compact Annular Slot Antenna for Millimeter-Wave MIMO(Multiple Input Multiple Output) Applications

This work presents the design of a compact annular slot antenna for millimeter-wave applications, addressing the challenge of achieving good isolation, stable performance, and reasonable gain on a cost-effective substrate. The antenna is designed on an FR4-epoxy substrate (ε<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">r</inf> = 4.4, tan δ = 0.02), which provides a balance between affordability and electrical performance. It operates within the 26–36 GHz frequency range and features a triple-port configuration. By using optimized slot positioning and a well-structured feed network, the antenna achieves an isolation of -28 dB while maintaining good gain and efficient radiation characteristics. Simulation and fabrication results confirm its performance, demonstrating its suitability for high-frequency communication systems. Additionally, its capability to support MIMO applications makes it a strong candidate for next-generation wireless networks.