The objective of this project is to develop a fully-integrated biotelemetry device for short-range multi-channel wireless recording of neurological signals. Microwave backscattering and nonlinear properties of Barium-Strontium-Titanate (BST) capacitors are used to form a passive frequency-multiplexed system for multi-channel telemetry of biologically created potentials, or bio-potentials. The implantable device is composed of a multi-port matrix of miniature antennas and integrated thin-film BST harmonic mixers and is coupled to an array of chronically implanted microelectrodes that sense the neurological signals. The implant is interrogated by using a 5-GHz radio frequency (RF) tone sent by the external transmitter. The implant emits a double sideband suppressed-carrier amplitude modulated (AM) backscatter RF signal at a frequency 10 GHz. The amplitude of the backscattered signal contains the bio-potential information that can be detected using a sensitive external receiver. Multi-channel communication is achieved using a frequency-multiplexed system, in which interrogation at each frequency results in a read out on a different node. With an approximate size of 10 cubic millimeters per channel, the passive microwave frequency backscatter system achieves the characteristics of miniature size and low power consumption. It is suitable for chronic implantation on the surface of the cerebral cortex or spinal cord of research or clinical subjects.
Broader Impact:
Breakthroughs in instrumentation design can provide the foundation for new capabilities in human-machine interactions. Compact wireless neuro-interfaces are required to allow implantation with minimal trauma and to achieve long term stability. Multiple channel wireless interfacing capability is necessary for interacting with the complex human nervous system. Such a capability will allow us to achieve a more sophisticated knowledge of the human body, and enables an effective way to use neural processes for controlling the outside environment. These devices have the potential to address applications in neurological recording and control. Development of the laboratory capabilities and test beds necessary for this project creates new opportunities for undergraduate student participation in summer internships and senior design projects. The project also furthers the capability of Arizona State University in serving students from underrepresented groups by increasing opportunities for their active involvement in research.
