Design of a Modulator and Demodulator for UHF RFID Readers

This paper presents a modulator and a demodulator designed for UHF RFID readers.The proposed circuits are designed and implemented in a 0.18μm CMOS technology and measurement shows that the modulator has an input 1dB compression point of 14dBm,insertion loss of 1.17dB,and isolation of 33dB.The demodulator has an input 1dB compression point of 5dBm,noise figure of 9dB,and voltage conversion gain of 4.9dB,which is negative in the conventional structure.Neither dissipates DC power.