An ultra-low-power RF transceiver for WBANs in medical applications

Abstract

Abstract: A 2.4 GHz ultra-low-power RF transceiver with a 900 MHz auxiliary wake-up link for wireless body area networks (WBANs) in medical applications is presented. The RF transceiver with an asymmetric architec-ture is proposed to achieve high energy efficiency according to the asymmetric communication in WBANs. The transceiver consists of a main receiver (RX) with an ultra-low-power free-running ring oscillator and a high speed main transmitter (TX) with fast lock-in PLL. A passive wake-up receiver (WuRx) for wake-up function with a high power conversion efficiency (PCE) CMOS rectifier is designed to offer the sensor node the capability of work-on-demand with zero standby power. The chip is implemented in a 0.18 m CMOS process. Its core area is 1.6 mm2. The main RX achieves a sensitivity of –55 dBm at a 100 kbps OOK data rate while consuming just 210 A current from the 1 V power supply. The main TX achieves C3 dBm output power with a 4 Mbps/500 kbps/200 kbps data rate for OOK/4 FSK/2 FSKmodulation and dissipates 3.25 mA/6.5 mA/6.5 mA current from a 1.8 V power supply. The minimum detectable RF input energy for the wake-up RX is –15 dBm and the PCE is more than 25%. Key words: ultra-low-power; RF transceiver; fast lock-in PLL; passive wake-up receiver; on-off keying; fre-quency shift keying DOI: 10.1088/1674-4926/32/6/065008 EEACC: 2220 1