Computer Aided Design of an Active Notch Filter for HF Band RFID

摘要

In a passive RFID system a single antenna is used for both transmitting and receiving purpose into a reader/interrogator. So it is obligatory to use a switching circuit or a filter circuit to isolate the sensitive circuit of the receiver input from the transmitting high power and voltage. A great opportunely for the engineers and designers, that the RFID uses a single carrier frequency for both transmission and reception purpose, this makes easy to design a notch filter for protect the sensitive input circuit from the transmitted carrier power and to extract the information from the modulated backscattering signal from the tag. The design and implementation of the notch filter is simpler than a switching circuit. In this paper we stated the design of an improved second order 13.56 MHz active notch filter using Wien-Notch topology for a high frequency band RFID reader/interrogator. The design was simulated and verified by using different types of mathematical and simulation software tools.