Our everyday life is unimaginable without wireless information and communication technologies. Since 2019, 5G digital systems have offered improved speed, bandwidth, and decreased energy consumption. Mobile operators invest $160 billion worldwide in the deployment of 5G each year. Over the last decades, RF filters based on Surface Acoustic Wave (SAW) occupied the entire market. But their usage for 5G high-band (26 GHz in EU) is impossible. Moreover, the utilisation of Bulk Acoustic Waves (BAWs) is still left to be explored due to their significant damping, challenges with confinement, and complex fabrication. The solution is offered by the propagating excitation in the spin system of a solid magnetic body - Spin Waves (SWs), which can efficiently replace acoustic waves in RF devices for all frequency bands. The key advantages of SWs are: (i) frequency range from 1GHz up to hundreds of GHz, (ii) manufacturability of SW transducers using conventional photolithography, (iii) strong confinement of SWs, and (iv) additional nonlinear functionalities.
The ERC StG MagnonCircuits project was completed with great success, providing the methodology and know-how for the fabrication and characterization of magnonic nano-structures, exploring the physical properties of SWs in them, and identifying robust, reliable and efficient phenomena for applications.
The project ERC-PoC "5G-Spin" was designed to give an impetus to the implementation of the scientific and methodological results obtained in the framework of the ERC-SG "MagnonCircuits" towards applied physics. Despite the fact that the proposed novel technology is still quite young and requires further laboratory development, the "5G-Spin" PoC has been extremely successful in forming a unique team of leading researchers actively addressing the challenges of the proposed new technology, in establishing contacts with potential industrial partners, and in carrying out a series of PR activities to raise awareness of the new spin-wave RF technology. On the scientific and technological side, the main challenges of the technology were identified and ways to overcome them were proposed and tested. Thus, the theoretical model of the high-efficiency spin-wave transducers was developed, a conceptually novel design of the transducers was presented, the solution for bias-free spin-wave RF devices was introduced and tested, the linearity of the operating characteristics of the RF devices as well as the maximum operating microwave power were defined theoretically, numerically and experimentally. The first proof-of-concept RF filters were designed, fabricated and characterized. The main ideas developed during the project were formulated in a patent application.
In summary, the ERC Proof of Concept "5G-Spin" project has initiated a prospective, but long-term and systematic research process for the development and benchmarking of the completely novel 5G RF spin-wave application with the potential to replace the currently used SAW- and BAW-based technologies in future communication systems.
