PASSIVE WIRELESS ACTUATOR CONTROL AND SENSOR SIGNAL TRANSMISSION

A new wireless communication method, based on absorption modulation, is presented for bidirectional data exchange between a small implanted module and an external control unit. The implanted module containing actuators and sensors operates without a battery or active RF transmitter. Energy and remote control data are received from an external RF field. The retransmission of sensor data is carried out on the same RF field by modulating the absorption rate. The field of application is multichannel telemetry and closed-loop operation of feedback control systems within long time periods but short distances. Almost any type of actuator and sensor can be supplied and operated, since the energy transfer exceeds 50% efficiency and the information capacity may exceed 1 Mbit/s. Except for the small loop antenna, the whole circuit may be realized on a substrate or hybrid. © 1990.