Pat.#5630216:		Micropower RF transponder with superregenerative receiver and RF receiver with sampling mixer
INVENTORS:		McEwan; Thomas E., Livermore, CA
ASSIGNEES:		The Regents of the University of California, Oakland, CA
ISSUED:		May 13, 1997
FILED:		Sep. 6, 1994
ABSTRACT: A micropower RF transdponder employs a novel adaptation of the superregenerative receiver wherein the quench oscillator is external to the regenerative transistor. The quench oscillator applies an exponentially decaying waveform rather than the usual sinewave to achieve high sensitivity at microampere current levels. Further improvements include circuit simplifications for antenna coupling, extraction of the detected signal, and a low-voltage bias configuration that allows operation with less than a 1-volt rail voltage. The inventive transponder is expected to operate as long as the battery shelf life.