Project WISDOM

Wideband Low-Cost Smart Passive and Active Integrated Antennas for THz Wireless Communications

General Information

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.

Goals of this research are wideband passive antennas and arrays, THz design in CMOS, 3D-on-CMOS Chip level antenna, an antenna array prototype and a chip array integrated with antenna array.

WISDOM proposes a significant advance towards the design and fabrication of smart, wideband and low-cost THz devices. In order to do so, the consortium is built from a very complementary expertise, with knowledge on both 3D printing, antenna, THz circuit and systems. A first key element of WISDOM, is the use of 3D inkjet printing for fast fabrication of THz passive and active antennas. This approach will be combined with THz circuit designs in CMOS. Using multi-material 3D inkjet printing of functional materials to simultaneously deposit conductive and dielectric materials; including thermal and UV rapid solidification of deposited structures, efficient coupling between on-chip signals to free-space radiation will be achieved.

This will lead to an important breakthrough that combines two cheap and high-volume technologies, paving a path to consumer-oriented THz products. A second key element is the combination of the 3D-on-CMOS printing technology with spatial-power combining array antennas, in order to develop highly-efficient THz beams that overcome the increased free-space path loss that prevents THz consumer products today. In WISDOM, we also plan to demonstrate the concepts with a smart spatial power-combining active array architecture for wideband THz wireless communications.

To top

Technologies

Due to the use of 3D printing (for antennas) and CMOS process (for circuits), it dramatically reduces the cost of THz devices and systems while providing significant advances in THz frontend adaptability. A number of wideband antenna elements, arrays, on-chip active antennas as well as THz front ends circuits (>300 GHz) will be designed, fabricated and measured.

For this project the universities are working with THz antennas and systems because these are the key components for future wireless communication. In case of THz antennas, their design is challenging due to the consideration of fabrication technologies, materials and measurement techniques during the design.

To get to a solution towards cost effective high performance mm-wave front-ends the project members merge four technologies:

advances in the highly dense, multilayer PCB / LTCC technology
advances of additive manufacturing
advances of SiGe / CMOS and GaN semiconductor technologies
advances in planar antenna / filter design / EM simulations.

To top

Consortium and tasks

The WISDOM consortium is composed from partners contributing complementary competences to the project. These competences can be summarized as follows :

From TU Graz side, we investigate structures which improve the coupling between the electromagnetic field from an on-chip antenna to the 3D printed horn. For this purpose, we focus on planar lenses which are designed to concentrate the energy of emitting antennas. This behavior can be also replicated using low profile structures, placed on top of the antenna. If such structures are manufactured using 3D printing, a low-cost and efficient approach of the implementation of these lenses can be derived.

To top

Planar Lenses

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.

Examples of unit cells of a planar lens and their focal properties

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.

Test setup to characterize the properties of the planar lens

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.

Examples of the manufactured unit cells of the lenses

To top