Multiple Frequency Band Acoustic Transducer Arrays

• Main Authors: Angelsen, Bjorn Atle Johan, Myhre, Ola Finneng
• Format: Patent
• Language: English
• Published: 24.05.2018
• Subjects: BASIC ELECTRONIC CIRCUITRY; ELECTRICITY; FOR PERFORMING MECHANICAL WORK IN GENERAL; GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS IN GENERAL; IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; METHODS OR APPARATUS FOR GENERATING OR TRANSMITTING MECHANICALVIBRATIONS OF INFRASONIC, SONIC, OR ULTRASONIC FREQUENCY; PERFORMING OPERATIONS; RESONATORS; TRANSPORTING

A structure of an acoustic transducer array probe for transmission of acoustic waves from a front radiation surface into an acoustic load material, where said acoustic waves can have frequencies in a high frequency (HF) band and further lower frequency (LF1, . . . , LFn, . . . , LFN) bands with N≥1, arranged in order of decreasing center frequency. The acoustic waves are transmitted from separate high and lower frequency arrays stacked together with matching layers in a thickness dimension into a layered structure, with at least a common radiation surface for said high and lower frequency bands. At least for said common radiation surface at least one lower frequency LFn electro-acoustic structure (n=1, . . . , N) comprises a piezoelectric array with an acoustic isolation section to its front face. The acoustic isolation section includes to the front a section composed of a sequence of L≥3 matching layers with interchanging low and high characteristic impedances, where the front layer of said section is one of i) a lower characteristic impedance layer, and ii) a higher characteristic impedance layer, and where at least one lower characteristic impedance layer is made of a homogeneous material.