Design and implementation of SAW reader receiving circuit

Surface acoustic wave (SAW) devices find numerous applications in sensor fields, as well as in Radio Frequency Identifications (RFID). SAW RFID system works similar to conventional radar system. The reader of SAW RFID system is based on delay line device and time-domain interrogation. The SAW Reader is composed of transmitting circuit and receiving circuit. The transmission circuit sends inquiries pulse to the SAW tag, and the receiving circuit demodulates echo signal, samples and stores the demodulated signal. The receiving circuit is designed and fabricated with IQ demodulator chip, low-noise baseband amplifier, ADC driver, high-speed ADC, FPGA and SRAM. Measured results obtained by a built reader and SAW tags bonded to the antenna for an SAW RFID system are given and analyzed.