Basic Study of Application for Elasticity Control of Piezoelectric Lead Zirconate Titanate Materials using Negative-Capacitance Circuits to Sound Shielding Technology

We report a novel elasticity control technique for piezoelectric lead zirconate titanate (PZT) ceramics using an electric circuit that behaves as a "negative capacitor" (hereafter referred to as a negative-capacitance circuit) for application to sound shielding technology. A feature of this technology using an optimized negative-capacitance circuit is effective sound attenuation regardless of the PZT ceramic type or frequency ranges of the noise. In this experiment, we prepared three types of PZT ceramic with different dielectric and piezoelectric characteristics. We improved the circuit constants of negative-capacitance circuits for the three kinds of PZT ceramic with different physical properties. We measured the transmission loss attenuation factor of the three types of PZT ceramic in the frequency range from I to 100 kHz. We found that the transmission loss attenuation factors of all three types of ceramic were greater than 20 dB in the frequency range from I to 100 kHz.