A 43.2 μW 2.4 GHz 64-QAM Pseudo-Backscatter Modulator Based on Integrated Directional Coupler

This paper proposes a 2.4 GHz ultra-low power pseudo-backscatter modulator with an integrated directional coupler for wireless sensor network applications. In order to improve the performance of backscatter modulator for multilevel modulation, an integrated directional coupler is employed to isolate the radio frequency carrier wave from the modulated signal. As a result, the carrier wave can be modulated in radio frequency domain independently without being affected by reflection coefficient of a conventional backscatter modulator. For further reducing power dissipation, the modulator only employs buffers for output and implements modulation by passive circuits. The proposed modulator is demonstrated in a standard 40 nm CMOS 1P10M process and it achieves 64-QAM modulation at 3 Mb/s data rate by consuming only 43.2 μW with a supply voltage of 0.8 V.

[1]  Asad A. Abidi,et al.  CMOS mixers and polyphase filters for large image rejection , 2001, IEEE J. Solid State Circuits.

[2]  Giuseppe Palmisano,et al.  A 90nm CMOS 5Mb/s crystal-less RF transceiver for RF-powered WSN nodes , 2012, 2012 IEEE International Solid-State Circuits Conference.

[3]  Asad A. Abidi,et al.  A tunable integrated duplexer with 50dB isolation in 40nm CMOS , 2009, 2009 IEEE International Solid-State Circuits Conference - Digest of Technical Papers.

[4]  J. Teizer,et al.  Quadrature Amplitude Modulated Backscatter in Passive and Semipassive UHF RFID Systems , 2012, IEEE Transactions on Microwave Theory and Techniques.

[5]  Kathleen Philips,et al.  9.7 A 0.33nJ/b IEEE802.15.6/proprietary-MICS/ISM-band transceiver with scalable data-rate from 11kb/s to 4.5Mb/s for medical applications , 2014, 2014 IEEE International Solid-State Circuits Conference Digest of Technical Papers (ISSCC).

[6]  Nuno Borges Carvalho,et al.  Quadrature Amplitude Backscatter Modulator for Passive Wireless Sensors in IoT Applications , 2017, IEEE Transactions on Microwave Theory and Techniques.

[7]  Huailin Liao,et al.  A high frequency resolution digitally controlled oscillator with differential tapped inductor , 2015, 2015 IEEE International Symposium on Circuits and Systems (ISCAS).

[8]  S. J. Thomas,et al.  A 96 Mbit/sec, 15.5 pJ/bit 16-QAM modulator for UHF backscatter communication , 2012, 2012 IEEE International Conference on RFID (RFID).

[9]  Zhihua Wang,et al.  A 9.4 pJ/bit 432 MHz 16-QAM/MSK transmitter based on edge-combining power amplifier , 2017, 2017 IEEE International Symposium on Circuits and Systems (ISCAS).

[10]  Noboru Ishihara,et al.  13.8 A 5.8GHz RF-powered transceiver with a 113μW 32-QAM transmitter employing the IF-based quadrature backscattering technique , 2015, 2015 IEEE International Solid-State Circuits Conference - (ISSCC) Digest of Technical Papers.

[11]  W. Bachtold,et al.  Microwave backscatter modulation systems , 2000, 2000 IEEE MTT-S International Microwave Symposium Digest (Cat. No.00CH37017).

[12]  Mau-Chung Frank Chang,et al.  A 5.8 GHz 54 Mb/s Backscatter Modulator for WLAN With Symbol Pre-Distortion and Transmit Pulse Shaping , 2016, IEEE Microwave and Wireless Components Letters.