Sensitivity improved ZigBee RF receiver for a medical sensor

In this paper, a ZigBee based telemedicine monitoring system is presented with a 2.4 GHz ISM band sensitivity improved low-IF receiver for ZigBee sensor nodes. The receiver implemented is in 0.18 μm 1P6M RF CMOS process. The circuit is formed by a single-end dual band Low Noise Amplifier (LNA) that enhances the sensitivity of the ZigBee receiver by several dB - a key factor that extends the receiver range, a quadrature high gain and low noise current bleeding mixer and a quadrature parallel-coupled voltage-controlled oscillator (VCO). The receiver operates in the 2.4 GHz ISM band and complies with IEEE 802.15.4 (ZigBee) specifications. The circuit exhibits a low noise figure of 2.27 dB and dissipates only 14.6 mW with a 1.2 V supply voltage. This high sensitivity RF receiver is highly suitable for Telemedicine Monitoring System.