A device includes a stack of at least two piezoelectric layers configured to propagate a Lamb wave in a mode having an order corresponding to a number of piezoelectric layers of the stack. The stack includes a first piezoelectric layer and a second piezoelectric layer disposed on the first piezoelectric layer. The first piezoelectric layer has a first cut plane orientation, and the second piezoelectric layer has a second cut plane orientation complementary to the first cut plane orientation. The device further includes an interdigitated transducer (IDT) disposed on at least a top surface of the stack or a bottom surface of the stack. In some embodiments, the device is an acoustic resonator. In some embodiments, the device is an acoustic delay line.

A crystal element includes a vibration part, a holding part, an electrode part, and a recess that corresponds to a recess and/or protrusion. The vibration part has a pair of vibration-part main surfaces. The holding part is formed integrally with the vibration part to be connected to an outer edge of vibration part and has a pair of holding-part main surfaces and holding-part side surfaces. The electrode part is provided at the vibration-part main surfaces. The recess is located at the holding-part side surfaces.

A quartz crystal resonator that includes a quartz crystal element having main surfaces extending in a plane φ degrees around a Z axis of the quartz crystal element and θ degrees around an X′ axis of the quartz crystal element; and an electrode in contact with the quartz crystal element, where x=t/T≥0.01, |φ−(−98.6x.sup.3+114.0x.sup.2−22.3x+1.3)|≤5 and |θ−(−9.5x.sup.3−10.9x.sup.2+1.4x+35.3)|≤0.5, wherein T is a thickness of the quartz crystal element and t is a thickness of the electrode.

A quartz crystal unit comprising a quartz crystal resonator having a base portion, and first and second tuning fork arms connected to the base portion, the base portion having a length less than 0.5 mm and greater than a spaced-apart distance between the first and second tuning fork arms, each of the first and second tuning fork arms having a width less than 0.1 mm and a length less than 1.56 mm, and a plurality of different widths including a first width and a second width greater than the first width, at least one groove being formed in at least one of opposite main surfaces of each of the first and second tuning fork arms so that a length of the at least one groove is within a range of 0.3 mm to 0.79 mm, the quartz crystal resonator being housed in a case, and a lid being connected to the case.

An acoustic structure is provided. The acoustic structure includes an acoustic resonator structure configured to resonate in a series resonance frequency (e.g., passband frequency) to pass a signal, or cause a series capacitance to block the signal in a parallel resonance frequency (e.g., stopband frequency). The parallel resonance frequency may become higher than the series resonance frequency when the tunable capacitance is lesser than or equal to two times of the series capacitance (C.sub.Tune≤2C.sub.0), or lower than the series resonance frequency when the tunable capacitance is greater than two times of the series capacitance (C.sub.Tune>2C.sub.0). In this regard, the acoustic structure can be configured to include a tunable reactive circuit to generate the tunable capacitance (C.sub.Tune) to adjust the parallel resonance frequency. As such, it may be possible to flexibly configure the acoustic resonator structure to block the signal in desired stopband frequencies.

A crystal oscillator includes an oscillating substrate, a hollow frame, a first electrode, and a second electrode. The oscillating substrate includes a main oscillating region and a thinned region that has a thickness smaller than that of the main oscillating region. The first and second electrodes are disposed on a first surface of the oscillating substrate and a second surface opposite to the first surface, respectively. The hollow frame is disposed on the second surface. The second electrode includes a second electrode portion that has at least one opening in positional correspondence with the thinned region. A method for making the crystal oscillator is also provided herein.

A microwave dielectric component (100) comprises a microwave dielectric substrate (101) and a metal layer, the metal layer being bonded to a surface of the microwave dielectric substrate (101). The metal layer comprises a conductive seed layer and a metal thickening layer (105). The conductive seed layer comprises an ion implantation layer (103) implanted into the surface of the microwave dielectric substrate (101) and a plasma deposition layer (104) adhered on the ion implantation layer (103). The metal thickening layer (105) is adhered on the plasma deposition layer (104). A manufacturing method of the microwave dielectric component (100) is further disclosed.

A vibrator device includes a vibration element including a vibration portion and a fixed portion, a supporting member to which the fixed portion is attached to support the vibration element, and a first substrate to which the supporting member is attached, the supporting member includes a attaching portion attached to the first substrate, and A1≥A2 is satisfied in a case where an area of a rectangular region including the fixed portion is A1 and an area of a rectangular region including the attaching portion is A2 in a plan view seen from a thickness direction of the vibration element.

A vibrator device includes a vibration element including a vibration portion and a fixed portion, a supporting member to which the fixed portion is attached to support the vibration element, and a first substrate to which the supporting member is attached, the supporting member includes a attaching portion attached to the first substrate, and A1≥A2 is satisfied in a case where an area of a rectangular region including the fixed portion is A1 and an area of a rectangular region including the attaching portion is A2 in a plan view seen from a thickness direction of the vibration element.

A doubts rotated quart/crystal resonator comprises a cantilever-mounted doubts rotated resonating element having a line of geometrical symmetry running from a supported end to a free end which is not perpendicular to the resonating element's crystallographic/axis. A method of manufacturing the crystal resonator comprises cutting a doubly rotated quartz crystal plate with x.sup.I and z.sup.I axes defining the plate's plane into one or more resonating elements at a non-zero degrees in-plane rotation angle in relation to the plate's x.sup.I axis. The resonator has reduced sensitivity to mechanical acceleration.