A new wide temperature range temperature measurement method for saw RFID tags

Abstract

The invention provides a novel wide temperature range temperature measurement method of a SAW RFID tag. The method comprises steps of distributing frequency difference at the biggest frequency interval of searching signals emitted by a reader, and selecting frequency difference of multiple searching signals meeting the condition that phase difference fuzziness resistance is performed for construction of a congruent equation; selecting two reflecting gratings in any position in the SAW RFID tag; extracting fuzzy phases of echo signals generated by the reflecting gratings of each frequency searching signal so as to obtain the fuzzy phase difference corresponding to each group of frequency difference of each reflecting grating; through the multiple groups of frequency difference and the fuzzy phase difference, constructing the congruent equation to achieve phase difference fuzziness resistance; in the standard temperature, calibrating fuzziness-free phase difference between the reflecting gratings; and comparing the fuzziness-free phase difference between the reflecting gratings in the actual environment temperature where the SAW tag is arranged with the fuzziness-free phase difference between the reflecting gratings in the standard temperature, thereby obtaining the temperature change quantity relative to the standard temperature and achieving temperature measurement.

Description

technical field [0001] The invention relates to the technical field of measurement, in particular to a novel wide temperature range temperature measurement method of a SAW RFID tag. Background technique [0002] Radio Frequency Identification (RFID) uses radio frequency signals to identify targets and obtain relevant data. It is a non-contact tag technology. It is precisely because of its non-contact characteristics that no manual intervention is required in the identification process, which is conducive to the realization of system automation. In recent years, RFID technology has been widely used in logistics management, anti-counterfeiting, animal husbandry monitoring and management, automatic highway toll collection, tracking and positioning. [0003] The radio frequency tag using surface acoustic wave (Surface Acoustic Wave, SAW) technology is a purely passive radio frequency identification technology without any semiconductor integrated circuit chip. The RFID system b...

AI Technical Summary

Problems solved by technology

However, this method has serious shortcomings. If there are too many temperature-measuring reflective grids, the coding capacity of the SAW tag will be seriously reduced.

Even if only three temperature-measuring reflective gratings have been placed to achieve high temperature measurement accuracy, due to the existing method to solve the phase 2π ambiguity problem, it is necessary to construct the second and third reflective gratings at standard temperature with a phase difference different from that of the first , The phase difference between the two reflective gratings is sufficiently small, so that the change of the difference in the SAW tag within the applied temperature range does not exceed 2π, this processing method limits the temperature measurement range of the SAW tag

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