Investigation of Acoustic Signal Distortion in FR-4 Laminate Structures for PEA Calibration

Abstract

The pulsed electro-acoustic (PEA) method is widely used to measure space charge distribution in dielectric materials, and its measurement accuracy strongly depends on the transfer function and gain coefficient obtained during system calibration. Conventional calibration structures based on multi-layer epoxy resin are sensitive to thermal and mechanical stresses, and their preparation process is relatively complex, which reduces experimental repeatability. To improve the stability and controllability of the calibration structure, this paper proposes the use of FR-4 laminates, commonly used as printed circuit board substrates, as an alternative solution. The FR-4 laminated structure provides precise thickness control, high mechanical stability, and convenient multilayer stacking. Preliminary PEA experiments were conducted to evaluate the influence of the FR-4 structure on acoustic signal propagation through waveform comparison and quantitative waveform metrics. The results provide an experimental basis for constructing a structurally stable and modular PEA calibration structure and support the development of improved calibration models.