WISDOM - Smart Wideband Low Cost Passive and Active Integrated Antennas

Wireless communications has become a core component in our daily life. Many mobile and stationary devices in our environment provide wireless interfaces we can connect to. Due to the extensive deployment of mobile devices, there is an exponentially increasing demand from costumers for high-speed mobile data. Already today by far the biggest amount of wireless data transfer is produced by mobile phones. However the spectrum bands that are being used in today`s communication schemes are getting very congested. This causes severe interference and distortion issues that significantly affect a reliable high speed data transfers. By moving to THz frequency bands, one could use the large amount of unallocated bandwidth to achieve communication speeds up to 100Gbps. Research on THz communication systems is currently focusing on expensive III-V semiconductor technologies, which are well suitable in low quantity but high performance commercial and military applications such as radar guidance or base stations. The proposed research work is targeting an implementation of THz communication systems with very low-cost devices that can be mass-produced by utilizing a Silicon CMOS process. To overcome the system limitations caused by the intrinsic lower power of the CMOS process it requires a joint effort between circuit design, antenna implementation and packaging technology, which has not been undertaken on the same scale as this project aims to do. Besides the utilisation of the low cost CMOS semiconductor process a key element of our research project is the usage of 3D inkjet printing technology for fast, accurate and low cost fabrication of THz passive and active antennas. The transition from the silicon CMOS chip to the radiating antenna is crucially important for the system performance. On-chip integrated antennas in silicon are not performing very well therefore we propose the utilisation of multi-material 3D inkjet printing of functional materials to simultaneously deposit conductive and dielectric materials for efficient coupling between silicon on-chip signals to free-space radiation. The combination of the 3D-on- CMOS printing technology with 3D printed spatial-power combining array antennas, in order to develop highly-efficient THz beams will lead to an important breakthrough that combines two fairly cheap and high-volume technologies (CMOS and 3D inkjet printing) paving a path to consumer- oriented THz products. The proposed project will demonstrate that low cost consumer THz communication systems are feasible with interdisciplinary cooperation and a research effort where the expertise in several fields is combined.

The goal of the WISDOM research project was to provide new concepts and approaches in the design and fabrication of low-cost and broadband devices in the THz range (100GHz to 400 GHz). These frequencies and the objective of low-cost manufacturing processes is specifically focused on the next telecom and mobile network generation 6G. For this purpose, an international consortium (Graz University of Technology in Austria (TUG), University of Kent in the UK, University of Warwick in the UK, and KU Leuven in Belgium) was composed providing expertise in the areas of integrated circuit and antenna design as well as enhanced 3D printing techniques. In the framework of this project, the emphasis at the Institute of Microwave and Photonic Engineering at Graz University of Technology was on the investigation of planar lenses, both, implemented as Antenna-in-Package (AiP) or located right above the Antenna-on-Chip (AoC). We were able to enhance the transition between a miniaturised antenna located at the integrated circuit to a corresponding high gain antenna. By this approach, the effectiveness of the transmission and the capability to focus the radiated beam is significantly improved. Within this project, we have investigated novel implementations of planar lenses that are suitable for additive manufacturing (3D printing) for future 6G mm-wave applications. Additionally, we were looking at refining the existing 3D printing technologies and corresponding materials to be more suitable for mm-wave applications.