Ultra-low-power Wake-up Receivers for Wireless Sensor Networks

Abstract

This thesis presented two ultra-low-power wake-up receivers (WuRx) for wireless sensor network applications They featured narrow band operation at the widely used industrial scientific medical (ISM) band and were capable of receiving and demodulating the on-off keying (OOK) and frequency-shift keying (FSK) modulated wake-up signal respectively The first OOK WuRx was based on direct-detection topology using the proposed fully-differential complementary current-reuse RF detector embedded with input matching network obviating the need of power-thirsty RF low noise amplifier (LNA) and local oscillator (LO) It was fabricated in 0 18-?m CMOS technology featured -65 dBm sensitivity with 400 kbps data rate at 2 4 GHz while consuming only 4 5 ?W from a 0 8 V supply voltage As a result this work achieves the best energy efficiency of 11 25 pJ/bit compared to the state-of-the-art OOK WuRxs The second work a FSK WuRx was presented to balance the power budget between Rx and Tx The architecture was based on an injection-locked oscillator (ILO) as a FSK to ASK conversion circuit The ASK signal was followed by the direct detection topology to demodulate the wake-up signal The significant design limitation was the power constraint of the ILO This work utilized an external high-Q inductor (Q?150) fabricated on printed circuit board (PCB) as a loop antenna for receiving RF signal The chip was fabricated in 0 18-?m CMOS technology featured -70 dBm sensitivity and 200 kbps data rate at 433 MHz while consuming 7 4 ?W from a 1 V supply voltage It reached the energy efficiency of 37 pJ/bit

Date of Award	2015 Jan 19
Original language	English
Supervisor	Chin-Lung Yang (Supervisor)