Effects of conductive superstrate on USB dongle antennas

This article studies the effect of conductive superstrate on a MIMO antenna with two closely packed antenna element for Universal Serial Bus (USB) dongle application. The proposed antenna consists of two printed L-shaped strips, a truncated ground plane, and conductive superstrate. Whole structure is integrated like a rectangular box. The superstrate, distinguished into a notched rectangular and T-shaped conductive plates, uprights over the ground plane and the L-strips. Here, the superstrate can be regarded as an upper casing of the USB dongle. Due to the novel design, an LC resonant mode at lower band with reduce mutual coupling between the closely packed antenna elements is introduced. In our implemented prototype, the mutual coupling between antenna elements is less than 12 dB.