ACOUSTIC DEVICES INCLUDING ACOUSTIC MIRRORS CO-OPTIMIZED FOR LONGITUDINAL AND SHEAR WAVE REFLECTION, AND RELATED METHOD OF FABRICATION

• Main Authors: Schiek, Maximilian, Meister, Veit
• Format: Patent
• Language: English
• Published: 10.10.2024
• Subjects: BASIC ELECTRONIC CIRCUITRY; ELECTRICITY; IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS

An acoustic device includes a piezoelectric layer between a first, bottom electrode and a second, top electrode, and an acoustic mirror optimized for reflecting longitudinal waves and shear waves at a target operating frequency. The acoustic mirror includes lower acoustic impedance layers and at least one higher acoustic impedance layer. In an example, layers of the acoustic mirror alternate between lower impedance and higher impedance, with a first lower acoustic impedance layer adjacent to the bottom electrode, and a first higher acoustic impedance layer having a greater thickness than a second higher acoustic impedance layer. In another example, the acoustic mirror has a higher acoustic impedance layer with a thickness corresponding to at least half of a wavelength of the target operating frequency in the higher acoustic impedance layer. An acoustic device with an acoustic mirror optimized for both longitudinal waves and shear waves reduces energy losses for increased efficiency.