Injection locking based ultra low power radio frequency integrated circuits

Recent advances in radio frequency integrated circuit (RFIC) technology enable various innovative and versatile applications through ultra-low-power wireless link such as mesh sensor network, personal area network (PAN) and semi-active RFID. This thesis introduces energy efficient demodulator and transceiver design for wireless communications.;At the receiver front end, an ultra-low-power BPSK demodulator based on injection locked oscillators (ILOs) is introduced. Two second harmonic ILOs are employed to convert BPSK signals to ASK signals, which are then demodulated by an envelope detector to baseband. For sub-GHz applications, the ILOs are implemented using ring oscillators to allow compact chip area and ultra-low power dissipation. Bit error rate (BER) analysis of this demodulator indicates erroneous polarity flipping of demodulated bits due to phase noise of the ILO. The prototype chip is fabricated in a 65nm CMOS technology that consumes 228μW of power and occupies 0.014mm2 of die area. Measurement results reveal the demodulation of 750MHz 5Mb/s differential BPSK signal with a sensitivity of -43dBm. Theoretical BER analysis has been verified with erroneous flipping observed in the measurement and its probability close to the prediction.;Then, an innovative injecting locking based transceiver architecture for ultra low power operation is proposed. It applied the ILO based BPSK demodulator at the receiver side. The oscillating signal at one receiver ILO also injects to another transmitter ILO for accurate carrier generation. Thus local frequency synthesis circuit which consumes considerable portion of power in traditional transceiver is not required. This design is implemented in a 45nm CMOS SOI technology. Measurement results indicate that the transceiver achieves downlink demodulation of -35dBm BPSK signal at 5Mb/s data rate and uplink transmission of -23dBm ASK signal at 1Mb/s data rate with 0.93mA current consumption from 1V power supply.