A Novel MICS Receiver with FSK Dual Band Demodulator

Abstract

A low-complexity dual-band chirp FSK, direct conversion receiver is described in this paper. The receiver is dedicated to be used in the transceiver unit of a medical implantable wireless sensor. The system uses the RF band between 402 and 405 MHz. Two sub-bands frequencies employing chirped pulses are assigned for both binary information. The novelty of this work is the use of a Binary FSK LFM modulator, a direct conversion receiver and a simple and low power non-coherent BFSK envelope detection demodulator. Receiver performances are evaluated for all the input power dynamic range. Receiver front-end parameters are optimized using harmonic balance simulation. In order to improve receiver sensitivity, a low pass filter with controllable bandwidth between 40 and 300 KHz is used to avoid in-band interference. The receiver is able to achieve a noise figure of 5.5 dB, a receiver sensitivity of-93 dBm and a maximum data rate of 100Kbps. The simulated IIP3 and P-1dB are 12.6 dBm and 22.1 dBm respectively. A simple non coherent binary dual band FSK demodulator was used which is based on an envelope detector, integrate & dump, a sampling & hold and a liming circuit. The receiver was co-simulated with the dual band non coherent demodulator. The proposed receiver has a sensitivity of-93 dBm and a BER less than 10-3 .