title: The influence of spatial polarization distribution on spot poled PVDF membrane hydrophone performance.
abstract: The influence of spatial polarization distribution on spot poled PVDF membrane hydrophone performance was calculated and then experimentally verified using a one-dimensional model based on acoustic wave propagation through a layered medium. It is shown that the sensitivity of the hydrophone is markedly dependent on the spatial polarization distribution. It is also shown that there can be a significant difference between the voltage sensitivities measured in the same hydrophone probe depending on which electrode is actually facing the acoustic source. The measurements carried out in the frequency range 1-20 MHz indicate that this difference, while negligible below 2 MHz, may exceed 1.6 dB at higher frequencies. The model developed can also be used to determine the "effective" piezoelectric constant d33 of the PVDF material as a continuous function of frequency. Moreover, the model predicts the existence of a negative slope in the frequency response of the spot poled membrane hydrophone. The experimental confirmation of this prediction underscores the importance of using swept frequency methods during calibration measurements.
authors.affiliation: Physikalisch-Technische Bundesanstalt, Braunschweig, Germany.
authors.forename: B
authors.initials: B
authors.lastname: Fay
authors.forename: P A
authors.initials: PA
authors.lastname: Lewin
authors.forename: G
authors.initials: G
authors.lastname: Ludwig
authors.forename: G M
authors.initials: GM
authors.lastname: Sessler
authors.forename: G
authors.initials: G
authors.lastname: Yang
mesh_terms: D004560:Electricity; D008567:Membranes, Artificial; D011145:Polyvinyls; D014465:Ultrasonics; D005465:Fluorocarbon Polymers
chemical_list: D008567:Membranes, Artificial; D011145:Polyvinyls; C024865:polyvinylidene fluoride; D005465:Fluorocarbon Polymers