Base-Station Design for Passive UHF RFID Tags with Pulse-Width Modulated Backscattering
In this work, a base-station design is proposed for passive UHF RFID tags that use pulse-width modulation (PWM) in backscattering communication. The theoretical analysis of the PWM backscattering is presented along with the challenges it creates in the base-station design. The self-jamming issue in the base station is analyzed with a numerical case study. The theoretical analysis of the reverse communication channel is presented. A method is proposed for wired backscattering measurements, which models the path loss and reflection from the tag eliminating the need for wireless measurements in an anechoic chamber. It is shown by measurements that the base-station is capable of measuring the pulse-width of the backscattered signal with an error less than 1% at a distance of 2 meters.