A 30% Efficient High-Output Voltage Fully Integrated Self-Biased Gate RF Rectifier Topology for Neural Implants

Area of Science:

• Electrical Engineering
• Biomedical Engineering
• Microelectronics

Background:

• Neural implants require efficient power sources for wireless operation.
• Radio frequency (RF) energy harvesting offers a promising solution for powering implantable devices.
• Existing RF energy harvesters often face limitations in efficiency and output voltage.

Purpose of the Study:

• To develop and characterize a fully integrated RF energy harvester (EH) for neural applications.
• To achieve high power harvesting efficiency (PHE) and high output voltage.
• To evaluate the performance of the EH in a realistic neural implant scenario.

Main Methods:

• Design of a novel 10-stage self-biased gate (SBG) rectifier.
• Integration of an on-chip matching network.
• Fabrication using 65 nm CMOS technology.
• Characterization of EH performance, including PHE and output voltage.
• Evaluation through animal tissue stimulation tests.

Main Results:

• Achieved 30% end-to-end power harvesting efficiency (PHE).
• Supported high output voltage operation up to 9.3V at 1.07 GHz.
• Demonstrated >20% PHE over a 12-dB input range.
• The fabricated chip occupies a small area of 0.0732-mm².
• Successful animal tissue stimulation test validated its potential for neural implants.

Conclusions:

• The developed RF energy harvester is suitable for powering neural implants.
• The novel SBG rectifier topology enhances conductivity and efficiency.
• The integrated EH demonstrates high performance metrics for biomedical applications.