Next-Generation Quad-Port mmWave Antenna Using Diamond-Slot Perturbation

Abstract

This paper introduces the design and performance analysis of a compact quad-port multiple-input multiple-output (MIMO) antenna operating in the millimeter-wave frequency band for future high-data-rate wireless communication and 6G systems. The designed antenna structure is a compact quad-port MIMO antenna with a modified ground plane and slotted radiator design to improve impedance matching and port isolation. The designed antenna structure uses rotated square patches and defected ground structures to enhance current distribution and minimize mutual coupling between the ports. The simulated S-parameters indicate that all four ports of the proposed compact quad-port MIMO antenna have good impedance matching with reflection coefficients less than -10 dB in the operating frequency band of 22 GHz to 40 GHz. There are resonances at frequencies around 25 GHz, 30 GHz, and 34-35 GHz, which are appropriate for broadband millimeter-wave communication. The $\mathbf{S}_{\mathbf{2 2}}, \mathbf{S}_{\mathbf{3 3}}$, and $\mathbf{S}_{\mathbf{4 4}}$ characteristics closely follow $\mathbf{S}_{\mathbf{1 1}}$, confirming consistent performance across all ports. The 3D radiation patterns depict almost omnidirectional and constant radiation patterns with maximum realized gain values of 3.8-4.3 dBi. The radiation patterns also depict good symmetry and absence of pattern distortion, thus confirming the efficacy of the proposed geometry. The proposed antenna is compact in size, has a broad bandwidth, reasonable gain, and multi-port functionality, making it a promising candidate for millimeter-wave MIMO communication systems. The proposed antenna is suitable for 5G/6G wireless communications, high-speed indoor communication, and short-range high-capacity communication.