Brain Implantable End-Fire Antenna with Enhanced Gain and Bandwidth

Area of Science:

• Biomedical Engineering
• Electromagnetics
• Wireless Communication

Background:

• Brain-machine interfaces (BMIs) require efficient wireless communication.
• Implantable antennas face challenges from lossy biological tissues.
• Existing antenna designs may suffer from signal degradation and limited bandwidth.

Purpose of the Study:

• To propose and evaluate a novel end-fire radiating implantable antenna for BMIs.
• To achieve broadband operation (3-5 GHz) with a small footprint.
• To enhance antenna gain and radiation pattern stability within the brain.

Main Methods:

• Design and simulation of a Vivaldi antenna with comb-shaped slot arrays.
• Vertical implantation strategy to optimize radiation pattern and compensate for tissue loss.
• Fabrication and testing of an antenna prototype in a multi-layered brain phantom.

Main Results:

• The vertically implanted antenna demonstrated a 3 dB higher gain compared to horizontally implanted designs.
• Comb-shaped slot arrays reduced the resonant frequency by ~2 GHz and increased gain by >2 dB.
• Measured average gain was -15.7 dBi within the 3-5 GHz range.
• A link budget analysis confirmed reliable communication up to 10.8 cm.

Conclusions:

• The proposed implantable Vivaldi antenna is suitable for high-data-rate BMI applications.
• Vertical implantation and slot array design significantly improve antenna performance in biological environments.
• The antenna offers a viable solution for robust wireless communication within the brain.