Sensitivity of a Plate Pyroelectric Detector to Ambient Acoustic Noise: The Significance of the Perfectly-Clamped Mounting Condition

Published

January 1, 2004

Author(s)

John H. Lehman, Harald Gnewuch, Chris Pannell

Abstract

The unwanted sensitivity of a plate pyroelectric detector to airborne acoustic noise is critically dependent on the mounting conditions for the plate. We consider a plate in an isotropic acoustic pressure field oscillating at angular frequency. We analyze the situation in terms of a mechanically isotropic material, and show that for one type of boundary conditions, the so-called clamped boundary conditions, the strain-induced time-varying surface charges in various regions of the plate caused by the pressure, completely cancel out. This suggests that a significant reduction in noise sensitivity of a practical free-standing pyroelectric detector can be achieved by paying careful attention to the mounting conditions. We also derive the strains for the case of the less symmetric 3m case within the framework developed for the thin plate approximation, and show that the result is unchanged. This has implications for the design of pyroelectric detectors based on a stiff material such as LiTaO3.

Citation

Ferroelectrics

Volume

308

Pub Type

Journals

Keywords

acoustic noise, anisotropy, domain engineering, ferroelectric, mounting conditions, plate deformation, pyroelectric detector strain

Citation

Lehman, J. , Gnewuch, H. and Pannell, C. (2004), Sensitivity of a Plate Pyroelectric Detector to Ambient Acoustic Noise: The Significance of the Perfectly-Clamped Mounting Condition, Ferroelectrics (Accessed July 27, 2024)