Title: Специализация:
Author: Diagen
Last saved by: Bukina
Company: NIIRF

Specialization: 010700/19 «Physics»
Program: «Wave processes and methods of their study»
Head of the program: G.I. Makarov
Department of Radiophysics
Scientific adviser: docent N.P. Tihomirov
Reviewer: docent G.A. Druzhinin

Piezoelectric layer in the regime of sound receiving and acoustic media matching
Tcarapkin Sergei

In the first part of this paper piezoelectric layer is considered in the regime of sound receiving in which plane harmonic wave of the pressure falls to the layer. The electrical load is connected to the faces of the piezoelectric layer. Media adjoined to the piezoelectric layer is described by the values of wave impedances. Obtaining the expression for the flat piezoelectric layer sensitivity in one-dimensional approximation shown in the paper (obtaining the expressions for the cylindrical and spherical piezoelectric layer sensitivity in the approximation of the radial oscillations is also shown). The frequency dependence of the flat piezoelectric layer sensitivity is studied for different wave impedances of media adjoined to the piezoelectric layer and different values of electric load impedance.

According to the results of these studies one can conclude:

1. The frequency dependence of the flat piezoelectric layer sensitivity has a maximum at the frequency of the mechanical resonance. There is the area of sensitivity constancy at the lower frequencies
2. Sensitivity depends on the impedance of the mechanical load on the rear face. For an absolutely rigid rear face of piezoelectric layer resonance frequency is twice larger than frequency for an absolutely soft face, and sensitivity in quasi-static regime is twice smaller.
3. It is possible to increase the area of sensitivity constancy width by increasing the value of resistance connected to the faces of the flat piezoelectric layer.
4. Another maximum is appear in the frequency dependence of the flat piezoelectric layer sensitivity at the resonance frequency of the oscillatory circuit by connecting to the faces of the flat piezoelectric layer the reactance (inductance).
In the second part of the paper the expression for the reflection coefficient of the pressure wave from the piezoelectric layer is obtained and the ability to control the reflection coefficient by using a passive electrical load in a certain range of frequencies or a harmonic voltage generator at any range of frequencies is shown. On the basis of this expression an algorithm for acoustic media matching for both harmonic and pulse pressure wave is represented.
The list of publication
1. S.I. Tcarapkin. «Sensitivity of the flat piezoelectric layer in the dynamic regime of sound receiving». XIV All-Russian Scientific Conference of Students-radiophysicists. Abstracts. 2010г.
2. S.I. Tcarapkin. «Electric adjustment of the reflection coefficient of the pressure wave from the piezoelectric layer». XIV All-Russian Scientific Conference of Students-radiophysicists. Abstracts. 2010г.
3. S.I. Tcarapkin. «Active media matching for acoustic impulse pressure». XV All-Russian Scientific Conference of Students-radiophysicists. Abstracts. 2011г.