A 5.8 GHz CMOS ASK demodulator for the China electronic toll collection system

In this paper, a 5.8 GHz integrated CMOS amplitude shift keying (ASK) demodulator for the China electronic toll collection system (ETCS) is presented. The ASK demodulator modulates the 256 Kbps baseband signal with reference to the 5.8 GHz carrier frequency for low power dissipation. The design is implemented in a 0.18 μm CMOS process. The measurement results show that the proposed ASK demodulator can receive power as low as -38dBm with a 5.8 GHz carrier frequency, and modulation index can range from 30% to 100%. The circuit dissipates 200 μA with 1.8 V supply voltage and has a core die area of 0.17 mm².