mmWave 5G NR Cellular Handset Prototype Featuring Optically Invisible Beamforming Antenna-on-Display

Abstract

The reduced link margins caused by undesired blockage such as the user's hand and inherent limitations of beamsteering angles for planar antenna components constitute one of the most critical challenges for future mmWave mobile devices. This underscores the need for a new beamforming antenna strategy, which can enhance the foreside coverage with minimum compromise. This article provides a detailed overview of an mmWave beamforming antenna concept denoted as an optically invisible antenna-on-display (AoD), which can enhance the CDF, especially in the foreside direction of mobile devices such as cellular handsets. In contrast to existing antenna component strategies, the AoD is integrated within the view area of high-resolution OLED or LCD display panels of cellular handsets while remaining unnoticeable to the human eye through the use of nano-scale patterns. This allows the realization of highly precise beamforming in the foreside direction for large-screen mobile devices. The fundamental phased-array AoD strategy is introduced and compared with existing mmWave 5G beamforming antenna strategies for mmWave 5G NR cellular handsets. The operating mechanism of the mmWave 5G phased-array AoD component and its integration with existing wireless component architectures and a 537 ppi density OLED panel are considered. This concept is further refined by integrating a series of fabricated 28 GHz phased-array AoD components within a real-life mmWave 5G NR Android-based cellular handset prototype reported in the literature for the first time. The foreside beamforming characteristics at 28 GHz are experimentally studied followed by investigation of OTA measured EVMs using QPSK, 16- and 64-QAM mmWave 5G NR waveform signals in accordance with the 3GPP requirement.