Laboratory of Wireless Technologies

Scientific results:

Completely new types of transceiving antenna arrays for magnetic resonance imaging (MRI) of the human head have been developed, suitable for existing and prospective MRI scanners with an ultra-high field strength of 7.0 and 9.4 T (operating frequency of 300 and 400 MHz, respectively).

Thus, a new antenna array of 8 antenna elements in the form of combined pairs of curved wire dipoles was proposed and experimentally implemented. Due to the effect of near-field coupling of the active and passive dipoles within each antenna element, it was possible to expand the field of view of ​​MRI in order to cover the area of ​​the brain and spinal cord within the cervical spine. As a result, the proposed system has an extended field of view with the same efficiency compared to known designs in the literature. The results of testing the system on an operating 7 T tomograph have been obtained.

In addition, an array of 16 antenna elements of a new type (based on shortened microstrip resonators, which are new in the MRI technology) was proposed, simulated and designed, and its advantage in efficiency compared to existing designs in the literature was numerically demonstrated. The result was achieved by increasing the radiation level into the air and simultaneously reducing the internal dissipative losses of the antenna elements (by reducing the reactive near field level).

Passive resonant structures were also developed to control ultrasonic beams in water - a medium simulating the acoustic properties of  human body tissues to improve the efficiency of ultrasonic signal transmission and ultrasonic power. In particular, a new metalens for efficient ultrasound focusing in such media was proposed and studied, as well as a metasurface for matching the impedances of the acoustic transducer and the wave properties of the medium under consideration. The above structures are novel and, as components of acoustic energy transmission and diagnostic systems, will improve their characteristics.

In addition, a concept for constructing an acoustic metamaterial was developed for use in a passive noise suppression system for gradient systems of an MRI machine to improve patient comfort. Finally, during the project, an experimental prototype of a charging station for powering electronic devices implanted in the human body was developed and the main requirements for various component units and assemblies of the setup were determined. The proposed device consists of two main units: an energy harvesting and conversion unit and an implantable receiving unit. The energy harvesting and conversion unit consists of a receiving antenna, a voltage multiplier that rectifies the radio frequency signal, an energy storage device, a power control system, an inverter, and a transmitting piezoelectric plate. The implantable receiving unit of the power supply system for implantable electronic devices consists of a receiving piezoelectric plate, a voltage multiplier that rectifies the received ultrasonic signal, an energy storage device, a power control system, and a payload, which is an implanted electronic device.

Education and personnel occupational retraining:

A new educational track (elective direction) was developed and opened within the educational program "Wireless Technologies" in the Master's program of ITMO University called "Radiophysics of Metamaterials and Metasurfaces". 

Cooperation:

Technical University of Munich, Chair of Vibroacoustics Of Vehicles and Machines