RFID readers transmit a modulated RF signal to a "tag" device in close proximity. The simplest ones use ASK modulation to transmit data. The tag device converts the RF signal into DC power to power up it's integrated circuit and then demodulates the RF signal to extract commands and data from the RF signal. The tag has a characteristic impedence that it can modulate by shorting it's antenna terminals together selectively based on data bits it wants to transmit back to the reader. This "back scattering" technique causes the tag to selectively reflect the RF energy back to the reader where it is received and demodulated.
hello could u please explain ""The tag has a characteristic impedence that it can modulate by shorting it's antenna terminals together selectively based on data bits it wants to transmit back to the reader. This "back scattering" technique causes the tag to selectively reflect the RF energy back to the reader where it is received and demodulated.""
RFID
Re: RFID
