A Full-Duplex Radiotelemetry Transceiver

A Full-duplex radio transceiver suitable for telemetry and sensor networks operating in the license-free ISM band at 27 MHz and capable of wirelessly transferring information and energy is presented. The transceiver’s analog blocks include a crystal oscillator, ASK modulator-demodulator, and LDMOS power amplifier. The separation of transmission and reception paths is achieved by means of a passive non-magnetic circulator. Operating at 100 kb/s, the receiver consumes 13 mA from a 3.3V supply. The transmitter has a 55% efficiency for an output power of 34.87 dBm. The S-parameters measurements of the circulator show an isolation of 38 dB at 27 MHz and the insertion loss for the TX and RX paths of 3 dB.