PASSIVE WIRELESS SENSOR OF MAGNETIC FIELD ON SURFACE ACOUSTIC WAVES Russian patent published in 2021 - IPC G01H11/08 

FIELD: sensors.

SUBSTANCE: invention relates to passive piezoelectric sensors. The magnetic induction sensor contains a sealed housing, inside of which a piezoelectric sound conductor is located, on the working surface of which, in the first acoustic channel, a transceiver interdigital transducer (IDT) is located, loaded onto the antenna through leads in the housing, which is located outside the sealed housing, a reflective IDT and located outside sealed enclosure impedance. On the working surface of the piezoelectric sound conduit, parallel to the first acoustic channel, which is a measuring channel, a second is introduced - a reference acoustic channel, where another transceiver IDT is located, connected through leads in the housing to another antenna, and a reflective IDT, and the impedance through the leads in the housing is connected to the transceiver IDT located in the measuring acoustic channel, while the distance between IDTs in parallel measuring and reference acoustic channels differ by at least Nλ, where λ is the length of the SAW at the central frequency of the IDT located in the reference acoustic channel, N is the size of the IDT along the direction of propagation of the SAW in the SAW lengths (λ), all IDTs are made unidirectional. The difference between the center frequencies of the IDT in different acoustic channels is at least f₀/N, where large f₀ is the center frequency of the IDT in the reference acoustic channel.

EFFECT: increasing the reading range, sensitivity and accuracy of measuring the magnetic induction of the electromagnetic field.

5 cl, 11 dwg