P1H-1 Scattering Parameters Measurement for the Determination of Layered Media Properties with 25 Mhz Ultrasound

Non destructive evaluation (NDE) of layered media is of interest in many applications like food packaging and coating of substrates. In this paper, an approach for the measurement and reconstruction of acoustic parameters and thicknesses of layered media with high-frequency ultrasound (HFUS) in the 25 MHz range is presented. Ultrasonic two-port measurements are performed analog to conventional network analysis (NWA) of electrical networks in high-frequency metrology. A linear network model is employed to reconstruct layered media, which consist of discrete layers connected in series. Simulations and measurements, which were performed to evaluate the approach, are presented. The potential and limitations of the proposed technique is discussed