Short range passive telemetry by modulated backscatter of incident cw rf carrier beam. [Remote temperature measurements in cattle]

Modulated Backscatter Telemetry was developed as a means for reporting the temperature of cattle, along with an identification code for each animal. Objectives included low cost and passive (no battery) operation of the implanted transponders. This novel telemetry method should be useful in other applications. The paper describes the principle of operation and solutions to some of the problems encountered during the development. (auth)