Millimeter-Wave Antenna with Improved Bandwidth and Isolation for MIMO Applications

A multi-layer substrate integrated cavity (SIC) backed millimeter-wave antenna is proposed for multi-input multi-output (MIMO) applications. Owing to the stacked SIC architecture, the bandwidth and frequency selectivity of the antenna are significantly improved. Moreover, the MIMO antenna exhibits a high isolation between elements due to the constraints placed on the electromagnetic wave. To demonstrate the concept, a two-element MIMO antenna with a close spacing of 4.8 mm (0.44 λ @ 28 GHz) is designed and prototyped. Simulated and measured results show that the antenna has a broad bandwidth ranging from 26.5 to 30.2 GHz, good filtering performance, and a high isolation of over 16 dB.