Toward a distributed free-floating wireless implantable neural recording system

• Main Authors: Pyungwoo Yeon, Xingyuan Tong, Byunghun Lee, Mirbozorgi, Abdollah, Ash, Bruce, Eckhardt, Helmut, Ghovanloo, Maysam
• Format: Conference Proceeding
• Language: English
• Subjects: Application specific integrated circuits; Clocks; Electrodes; Implants; Probes; Silicon; Wireless communication
• ISSN: 1557-170X; 2694-0604
• DOI: 10.1109/EMBC.2016.7591726

To understand the complex correlations between neural networks across different regions in the brain and their functions at high spatiotemporal resolution, a tool is needed for obtaining long-term single unit activity (SUA) across the entire brain area. The concept and preliminary design of a distributed free-floating wireless implantable neural recording (FF-WINeR) system are presented, which can enabling SUA acquisition by dispersedly implanting tens to hundreds of untethered 1 mm 3 neural recording probes, floating with the brain and operating wirelessly across the cortical surface. For powering FF-WINeR probes, a 3-coil link with an intermediate high-Q resonator provides a minimum S21 of -22.22 dB (in the body medium) and -21.23 dB (in air) at 2.8 cm coil separation, which translates to 0.76%/759 μW and 0.6%/604 μW of power transfer efficiency (PTE) / power delivered to a 9 kΩ load (PDL), in body and air, respectively. A mock-up FF-WINeR is implemented to explore microassembly method of the 1×1 mm 2 micromachined silicon die with a bonding wire-wound coil and a tungsten micro-wire electrode. Circuit design methods to fit the active circuitry in only 0.96 mm 2 of die area in a 130 nm standard CMOS process, and satisfy the strict power and performance requirements (in simulations) are discussed.