A high data rate QPSK demodulator for inductively powered electronics implants

A high data transfer rate quadrature phase shift keying (QPSK) demodulator is proposed for wireless implantable electronic medical devices. The QPSK demodulator is an improved version from our previous binary phase shift keying (BPSK) demodulator, which is based on a modified Costas loop. Simulated QPSK model under Matlab Simulink obtained a data transmission rate of 8 Mbps with 13.56 MHz carrier frequency. Also, implemented differential topology of the proposed circuit using a 0.18/spl mu/m CMOS technology achieves a data transmission rate up to 4Mbps with the same carrier frequency. The simulated power dissipation of the schematic is 0.75mW under 1.8V power supply.