Flexible passive and wireless surface acoustic wave sensor and preparing method thereof

Abstract

The invention discloses a flexible passive and wireless surface acoustic wave sensor and a preparing method thereof. A piezoelectric layer is obtained through a traditional process, the small-size SAW sensor is prepared through the reduction process or an etching sacrificial layer transfer method, the high-quality piezoelectric layer growing on a hard substrate is retained, and flexibility of the piezoelectric layer is achieved; a planar helical antenna is printed on a flexible substrate through a transfer technology, the SAW sensor is printed on a strain isolator, the wireless passive function is achieved, the whole structure is compact and flexible, the sensor can work on a curved surface, for example detects human body temperature in real time when worn on the skin, has wide application prospects and has the advantages of being high in crystal quality and excellent in performance. Flexibility of the SAW sensor and the planar helical antenna is achieved, the sensor has the wireless passive function and is compact and flexible in whole structure and wearable, and the application field of the SAW sensor is broadened; the strain isolator and the system can provide reference for preparation of other flexible electronic devices.

Description

technical field [0001] The invention belongs to the field of wireless communication, and in particular relates to a flexible passive wireless surface acoustic wave sensor and a preparation method thereof. Background technique [0002] The core components of the surface acoustic wave SAW sensor include a piezoelectric substrate and an interdigital transducer deposited on the substrate. The interdigital transducer is a metal pattern similar to a crossed finger, which can realize the mutual conversion between sound and electricity. Surface acoustic sensors have the characteristics of small size, simple structure, high reliability, and high measurement accuracy. They can be used to measure various indicators such as temperature, humidity, pressure, gas, and biological parameters. Compared with traditional sensors, its most prominent feature is that it can realize passive wireless, so it works in harsh environments such as high temperature and high speed, strong magnetism and str...

AI Technical Summary

Problems solved by technology

The reported practice is to deposit or sputter a layer of piezoelectric film on flexible organic polymers to achieve flexibility, but due to the serious lattice mismatch between the flexible substrate and the piezoelectric film, the difference in thermal expansion coefficient between the two is too large, Due to the complex and harsh preparation process, the lattice quality and surface roughness of the obtained piezoelectric layer are usually much worse than those directly grown on the hard substrate. In addition, the flexible piezoelectric layer that can be grown by this method thin film is limited

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