The research project WISDOM (Wideband Low-Cost Smart Passive and Active Integrated Antennas for THz Wireless Communications) is funded by the Austrian Science Fund (FWF) and the CHIST-ERA funding program. It lasts from January 2017 until December 2019. The overall cost will be 7.9 Million euros. For this project the Graz University of Technology co-operates with the University of Kent, UK, KU Leuven ESAT-MICAS, Belgium, and the University of Warwick, UK.
The CHIST-ERA funding program is a coordination and co-operation activity of national and regional research funding organizations mainly in Europe and is supported by the Horizon 2020 Future and Emerging Technologies (FET) program of the European Union through the ERA-NET Co-fund funding scheme.
Consisting of several passive resonators, the basic principle of the planar lens is to create a structural synthesizes through the following three parts: In section (1) of the figure below an u-shaped gap antenna is presented. Consisting of a semicircle (B) and a dipole (C), in which (B) and (C) are united into one object, as an omega like structure, seen on the right hand side at section (2). All structures are intermittent stacked on each other (section (3) (A) and (B)). In the hereby created properties, the u-shape gap antenna acts as a coupling element. As predicted and illustrated in section (4), the energy of the electromagnetic wave is being focused into a beam like shape.
To demonstrate the described functionality of the concept a test setup was built at a frequency of 14 GHz. The unit cells of the planar lens discussed before were manufactured using a Rogers 4350B substrate. Multiple layers of single elements of the lens were stacked into a single array. With the help of 3D-printed vise the lens was positioned on top of a patch antenna, to measure its properties. The design of this measurement setup is visualized in the next figure. The approach allows a direct scaling of the structures to the frequencies used by the partners.
Examples of the manufactured unit cells for the lenses are presented in the next figure. By varying the size and dimensions of the unit cells the impact of manufacturing tolerances is considered. These structures are actually characterized. As soon as this step is accomplished the transition to higher frequencies is performed.