Power-over-Skin (Final Year Project)
NTU FYP exploring wireless power transfer using the human body as part of the path. 40 MHz capacitive coupling, matching networks, and PCB iterations.
Problem
Wearables and implantables need power without bulky batteries or cables. Can the body itself be part of the link?
My Role
Final-year researcher (NTU EEE FYP).
What I Built
TX/RX hardware, matching networks, custom PCB iterations, and a rectifier chain that successfully drove an LED through a human-body channel at 40 MHz.
Key Features
- 40 MHz capacitive coupling
- TX/RX matching network design
- VNA-based impedance measurements
- PCB iterations
- Schottky voltage doubler rectifier
- LED powered through body
- Rectifier efficiency via impedance-aware matching
Technical Details
Designed LC matching networks per VNA-measured impedances. Iterated PCB layouts in KiCad. Built a Schottky voltage-doubler rectifier and tuned for impedance-aware power transfer.
Hardest Challenge
The body channel changes with skin contact, hydration, and posture. Matching is a moving target.
Outcome / Result
Demonstrated end-to-end power transfer through-body — LED lit at the receiver side.
Learnings
RF intuition matters more than simulation. Touch the board, watch the VNA, iterate fast.
System diagram
TX coupling pad → human body channel → RX coupling pad → matching → rectifier → LED.
- 40 MHz capacitive coupling
- Impedance-aware matching
- Schottky voltage doubler
- Receiver LED lit through body