OLED Display-Integrated Optically Invisible Phased Arrays for Millimeter-Wave 5G Cellular Devices

This paper presents a display-integrated optically invisible phased array using the antenna-on-display (AoD) technology for millimeter-wave 5G cellular devices. Based on the proposed approach, a massive number of antennas can be embedded in organic light emitting diodes (OLED) or liquid crystal displays (LCD) of cellular devices, while consuming near-zero volume. To obtain simultaneously high optical transparency and electrical conductivity, diamond-grid shaped transparent electrodes are developed and analyzed. The designed and fabricated antenna element exhibits an impedance bandwidth of 3.62 GHz with a center frequency of 26 GHz and a measured realized gain of 1.78 dBi. The designed antenna element is extended to the 1x4 phased array which is assembled with the 5G beamformer board to verify the beamforming capabilities. Measured radiation patterns confirm that the proposed phased array module achieves a beam-steering range of 30 in the azimuth with the estimated maximum peak EIRP of 14.14 dBm at 28 GHz.