Thin-film piezoelectric resonator, filter and voltage-controlled oscillator

• Main Authors: ITAYA, KAZUHIKO, YASUMOTO, TAKAAKI, SANO, KENYA, YANASE, NAOKO, OHARA, RYOICHI
• Format: Patent
• Language: English; French; German
• Published: 10.09.2008
• Subjects: BASIC ELECTRONIC CIRCUITRY; ELECTRICITY; GENERATION OF NOISE BY SUCH CIRCUITS; GENERATION OF OSCILLATIONS, DIRECTLY OR BY FREQUENCY-CHANGING,BY CIRCUITS EMPLOYING ACTIVE ELEMENTS WHICH OPERATE IN ANON-SWITCHING MANNER; IMPEDANCE NETWORKS, e.g. RESONANT CIRCUITS; RESONATORS

A thin-film piezoelectric resonator includes a substrate (2), and first (71, 72, 74, 76, 77) and second (73, 75) excitation portions. The substrate includes first (21, 22, 24, 26, 27) and second (23, 25) cavities. The first excitation portion (71, 72, 74, 76, 77) is disposed over the first cavity (21, 22, 24, 26, 27), and includes a first electrode (4), a first piezoelectric material (5) and a second electrode (6) laminated successively. An overlapping region among the first electrode (4), the first piezoelectric material and the second electrode (6) defines a contour of a periphery of the first excitation portion (71, 72, 74, 76, 77). A first distance is defined as a distance from an end of the first excitation portion (71, 72, 74, 76, 77) to an opening end of the first cavity (21, 22, 24, 26, 27). The second excitation portion (73, 75) is disposed over the second cavity (23, 25), and includes a third electrode (4), a second piezoelectric material (5) and a fourth electrode (6) laminated successively. A second distance is defined as a distance from an end of the second excitation portion (73, 75) to an opening end of the second cavity (23, 25) and different from the first distance.