Design of Wireless Passive SAW Temperature Reader Based on Software Radio
At present,most of the resonant SAW reader RF circuits adopt discrete device design,which limits the overall operating frequency band of the system and complicates hardware design.To address these issues,this article proposes a software radio solution.The main part of the software radio system consists of ZYNQ and AD9361,and the RF transceiver port is added with LNA and PA for signal power amplification,and RF switches are used to isolate the transceiver.By transmitting sweep signals with a stepped frequency of 5 kHz,bandwidth of 1 MHz,and performing spectral analysis on the echo to obtain the maximum value,the resonant frequency is finally obtained.For the short duration of the SAW sensor echo,which results in insufficient resolution in FFT calcula-tion,a repeated acquisition is used to increase the data length,and the resolution of the reader is increased to 468.75 Hz.The experimental results show that the reader can correctly detect the temperature changes of the sensor.
surface acoustic wave(SAW)SAW resonatorAD9361software defined radio(SDR)ZYNQ
NETL
NSTL
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