PASSIVE SENSOR ON SURFACE ACOUSTIC WAVES Russian patent published in 2011 - IPC H01L41/08 

FIELD: physics.

SUBSTANCE: sensor has on a substrate 1 made from piezoelectric material an interdigital transducer 2 and two structures of metallic reflectors 3 and 4 for surface acoustic waves (SAW). The first structure of reflectors is provided as a reference element and the second is a detecting element. SAW reflectors 3 of the first structure and SAW reflectors 4 of the second structure have different sensitivity to the measured quantity. The interdigital transducer 2 is unidirectional and is placed such that the direction of propagation of SAW from it is opposite the natural unidirectionality of the piezoelectric material of the substrate 1. The direction of SAW from the reflectors 3 and 4 coincides with the natural unidirectionality of the piezoelectric material of the substrate 1, where the anisotropy coefficient of the reflected SAW γ≤0. SAW reflectors 3 and 4 are symmetrical on the direction of propagation of SAW and are separated from each other by the minimum possible clearance 5 or are not separated. SAW reflectors 4 of the second structure are coated on the entire surface by a layer of material 6 which is sensitive to the measured quantity.

EFFECT: reduced measurement errors, high sensitivity of the sensor and range of reading from said sensor, simple design of the device, high manufacturability and reliability.

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