Distance measurement device and method based on multi-band phase information of surface acoustic wave devices

Abstract

The invention discloses a distance measurement device and method based on multi-band phase information of surface acoustic wave devices, thereby measuring a distance between a reader and a sensor probe. The sensor probe comprises three surface acoustic wave devices: an SAW-RFID chip A, an SAW-RFID chip B, and a surface acoustic wave resonator. The working frequency band of the SAW-RFID chip A ranges from 2.4 GHz to 2.44 GHz, and the center frequency of the SAW-RFID chip A is 2.42 GHz. The working frequency band of the SAW-RFID chip B is from 2.44 GHz to 2.48 GHz, and the center frequency of the SAW-RFID chip B is 2.46 GHz. The working frequency band of the surface acoustic wave resonator is from 420 MHz to 440 MHz, and the center frequency of the surface acoustic wave resonator is 433 MHz.The reader has a phase information acquisition mode for acquiring three devices with different center frequencies. The method comprises the steps that phase information of the surface acoustic wave sensing devices of three different frequency bands is integrated by utilizing the characteristic that the center working frequencies of three surface acoustic wave devices forming the sensor probe arenot overlapped; and the distance between the reader and the sensor probe is measured by using a quadratic phase difference method to process phase information. Therefore, the high-precision distance measurement can be realized.

Description

technical field [0001] The invention relates to the technical field of surface acoustic wave sensors, in particular to a distance measuring device and method based on multi-band phase information of surface acoustic wave (SAW, Surface Acoustic Wave) devices. Background technique [0002] Wireless passive SAW-RFID integrates tags and sensors and has the following advantages: Since the surface acoustic wave sensor is composed of piezoelectric materials and does not contain semiconductor devices, it is a "coreless" device, so it only requires extremely low energy Can work, and then realize wireless passive. It relies on sound waves to work internally. Sound waves propagate on the chip surface with an accurate delay of ns level. The delay has an estimable and measurable change law, which can be distinguished from the delay of electromagnetic waves in space in theory. In the process of transmitting and receiving sensor echoes, by separating and accurately measuring the delay of ...

AI Technical Summary

Problems solved by technology

[0013] Aiming at the deficiencies in the prior art, the present invention provides a ranging method combining the phase information of multi-frequency SAW devices, respectively measuring the phases of the SAW-RFID and the resonator located at the same position, performing addition and subtraction operations on the phases, and calculating The unambiguous phase at the new frequency can solve the problem of inaccurate ranging caused by 360° phase ambiguity, and realize high-precision distance measurement

Images