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.

中文翻译：

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毫米波 5G NR 蜂窝手机原型具有光学不可见波束成形天线

由用户的手等不希望的阻塞导致的链路余量减少以及平面天线组件波束控制角度的固有限制构成了未来毫米波移动设备的最关键挑战之一。这强调了对新波束成形天线策略的需求，该策略可以以最小的妥协增强前端覆盖。本文详细概述了毫米波波束成形天线概念，称为光学隐形天线在显示器 (AoD)，它可以增强 CDF，尤其是在移动设备（如蜂窝手机）的前端。与现有的天线组件策略相比，AoD 集成在蜂窝手机的高分辨率 OLED 或 LCD 显示面板的可视区域内，同时通过使用纳米级图案保持人眼不明显。这允许在大屏幕移动设备的前向方向上实现高精度波束成形。介绍了基本的相控阵 AoD 策略，并与用于毫米波 5G NR 蜂窝手机的现有毫米波 5G 波束成形天线策略进行了比较。考虑了毫米波 5G 相控阵 AoD 组件的运行机制及其与现有无线组件架构和 537 ppi 密度 OLED 面板的集成。通过将一系列制造的 28 GHz 相控阵 AoD 组件集成到文献中首次报道的基于真实毫米波 5G NR Android 的蜂窝手机原型中，进一步完善了这一概念。实验研究了 28 GHz 的前端波束成形特性，然后根据 3GPP 要求使用 QPSK、16-QAM 和 64-QAM 毫米波 5G NR 波形信号对 OTA 测量的 EVM 进行了研究。