Dual-Band, Ultra-Thin MM-Wave Antenna with Shared Aperture on Flexible Substrate

A low-profile, flexible dual-band stacked patch antenna for millimeter wave mobile communication with a capacitive feed and parasitic elements to enhance the bandwidth has been introduced. This antenna operates at frequencies of 27.8-29 GHz and 37.5-38.7 GHz and has a thickness of only 270 um. The effects of the parasitic elements on the antenna's return loss and gain were studied, and results indicate that the single element patch antenna maintained a consistent boresight radiation pattern with a maximum gain of 6.82 dBi for the lower band and 6.22 dBi for the upper band. A 4x1 array antenna is also investigated which has 12.04 dBi of gain with $\pm 45^{\circ}$ of scan angle for the lower band and 12.84 dBi of gain with $\pm 30^{\circ}$ scan angle for the upper band. Total efficiency of the antenna is found to be 86% for the lower band and 71% for the upper band.