Integrated active antenna arrays with polarization multiplexing for broadband communications at W-band

本提案的主要目标是在W波段的宽带，圆极化天线的设计和其随后的集成与CMOS功率放大器的系统级封装，可用作有源辐射元件内的基于阵列的发射机。该项目应与柏林工业大学的Georg Böck教授密切合作完成，因为Böck教授的小组与上述CMOS功率放大器有关。W波段提供35 GHz的总带宽。与较低频带（例如，可以采用具有中等复杂度（3-4 bit/s/Hz）的UWB或60 GHz）调制方案。与较高频带（200 GHz及以上）相比，具有足够高的截止频率的CMOS工艺已经在商业上可用，使得电路和系统设计的技术障碍显著降低。天线阵列是有利的，因为一方面，它们实现了系统可扩展性，这意味着链路预算可以被适配以适应不同的应用场景。另一方面，它们是模拟或数字波束转向的先决条件，其可以用于经由定向视线（LOS）连接与用户通信，从而提高链路质量。一个目标是设计和制造一个简单、小型（例如2x 1或2x 2）的天线阵列演示器。所设计的天线元件应当是圆极化的，使得基站和用户的移动终端之间不需要对准。此外，通过利用两个正交偏振（左旋和右旋圆偏振），数据速率加倍。因此，所设计的天线元件支持两个独立驱动的极化（极化复用）。一个目标是设计和制造具有极化复用的有源天线元件。 由于WLAN/WPAN主要是客户市场，因此所采用的技术是低成本的立体光刻工艺。该工艺具有微米级的特征尺寸和通过聚合物的沉积和固化而良好控制的垂直生长，这使得能够实现用“标准”PCB或MMIC工艺（由于层厚度或有限数量的层）不能制造的结构（例如倾斜壁）。将有源元件直接封装到聚合物层中导致具有优化设计的互连的集成（子）系统，从而降低信号损耗。该提案的基本挑战是利用这些技术机会实现尽可能最佳的系统性能（例如：宽带宽、低损耗）。

The main goal of this proposal is the design of a wideband, circularly polarized antenna at W-band and its subsequent integration with a CMOS power amplifier to a system-in-package which may be used as an active radiating element within an array-based transmitter. The project shall be completed in close cooperation with Prof. Georg Böck, TU Berlin, as Prof. Böck‘s group is concerned with the above mentioned CMOS power amplifier. The W-band offers a total bandwidth of 35 GHz. Unlike lower frequency bands (e.g., UWB or 60 GHz) modulation schemes with moderate complexity (3-4 bit/s/Hz) may be employed. In contrast to higher frequency bands (200 GHz and above) CMOS processes with sufficiently high cutoff frequencies are already commercially available, so that the technological barrier for the design of circuits and systems is considerably lower. Antenna arrays are advantageous because, on the one hand, they enable system scalability, which means that the link budget may be adapted to suit different application scenarios. On the other hand, they are a prerequisite for analog or digital beam steering, which may be used to communicate with users via a directed line-of-sight (LOS) connection and thus improves the link quality. One goal is the design and fabrication of a simple, small (e.g. 2x1 or 2x2) antenna array demonstrator. The designed antenna element shall be circularly polarized so that there is no need for alignment between the base station and the user‘s mobile device. Further, by utilizing two orthogonal polarizations (left- and right-handed circular polarization) the data rate is doubled. The designed antenna element thus supports two independently driven polarizations (polarization multiplexing). One goal is the design and fabrication of an active antenna element with polarization multiplexing. Since WLAN/WPAN is mainly a customer market, the employed technology is a low-cost stereolithographic process. The process has a micrometer-scale feature size and well-controlled vertical growth by deposition and curing of polymers, which enables structures (e.g. inclined walls), which cannot be fabricated with `standard` PCB or MMIC processes (due to layer thickness or limited amount of layers). Direct packaging of active components into the polymer layers leads to integrated (sub)-systems with optimally designed interconnects and, thus, lower signal losses. The basic underlying challenge of the proposal is to use these technological opportunities to achieve the best possible system performance (e.g.: wide bandwidth, low losses).