Optical probe for input-impedance measurement of in vivo power-receiving microstructure

@article{Yeh2014OpticalPF,
  title={Optical probe for input-impedance measurement of in vivo power-receiving microstructure},
  author={Alexander J. Yeh and John S. Ho and Ada S. Y. Poon},
  journal={2014 IEEE Antennas and Propagation Society International Symposium (APSURSI)},
  year={2014},
  pages={1409-1410}
}
An optical method is proposed to measure the input impedance of a microstructure in vivo operating at microwave frequencies. It makes use of the non-linearity of an AC-DC conversion circuit and encodes the received power level to the pulse rate of an LED which can be accurately measured by a photodiode outside the tissue medium. An accurate measurement of the characteristics of the power-receiving structures in a wireless powering system greatly enhance the power transfer efficiency.