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

本提案的主要目标是设计一种w波段的宽带圆极化天线，并随后将其与CMOS功率放大器集成到系统级封装中，该系统级封装可以用作阵列发射机中的有源辐射元件。该项目将与柏林工业大学的Prof. Georg Böck密切合作完成，因为Böck教授的团队正在研究上述CMOS功率放大器。w波段的总带宽为35ghz。与较低频段（例如，UWB或60 GHz）不同，可以采用中等复杂度（3-4比特/秒/赫兹）的调制方案。与更高频段（200千兆赫及以上）相比，具有足够高截止频率的CMOS工艺已经商业化，因此电路和系统设计的技术障碍大大降低。天线阵列的优势在于，一方面，它们使系统具有可扩展性，这意味着链路预算可以适应不同的应用场景。另一方面，它们是模拟或数字波束控制的先决条件，可用于通过定向视距（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的，小的（例如2x1或2x2）天线阵列演示。所设计的天线单元应为圆极化，这样基站与用户移动设备之间就不需要对准了。此外，通过利用两个正交偏振（左旋和右旋圆偏振），数据速率翻倍。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多路复用的有源天线元件。由于WLAN/WPAN主要是客户市场，因此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，并且通过沉积和固化聚合物可以很好地控制垂直生长，从而实现“标准”PCB或MMIC工艺（由于层厚或层数有限）无法制造的结构（例如斜壁）。将有效元件直接封装到聚合物层中，形成具有最佳互连设计的集成（子）系统，从而降低信号损耗。该提案的基本潜在挑战是利用这些技术机会来实现最佳系统性能（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).