Acoustic Sensing using Radio Frequency Detection and Micromachined Membranes

1
Acoustic Sensing using Radio Frequency Detection
and Micromachined Membranes

• A transmission line, periodically loaded with
  micromachined capacitor cells, phase modulates an
  RF carrier as membranes respond to acoustic
  pressure.
• A sensitive electrical interferometer demodulates
  the RF signal to recover the acoustic signal.
• Each individual cell is vacuum sealed to reduce
  losses and fluctation/thermal noise.
• Predicted signal to noise can exceed 90 dB/Pa/Hz
  for a microphone of only 1 mm2 area.

UserSean Hansen, E. L. Ginzton Laboratory,
Stanford University Principal Investigator Prof.
Butrus T. Khuri-Yakub, E. L. Ginzton
Laboratory NNUN Site Stanford University