Abstract: The present invention provides a noise filter that can provide a wire linking a power source and a load along a desired path regardless of an installation location of the noise filter. A noise filter is connected to a wire of a wire harness linking a power source and a load and eliminates noise transmitted from the power source to the load. The noise filter includes a housing, a capacitor that is housed inside the housing, a ground terminal that is connected to the capacitor, and a noise filter wire that has a first end connected directly to the capacitor and a second end connected by splicing to a middle portion of the wire of the wire harness.

Abstract: An acoustic resonator device with low thermal impedance has a substrate and a single-crystal piezoelectric plate having a back surface attached to a top surface of the substrate via a bonding oxide (BOX) layer. An interdigital transducer (IDT) formed on the front surface of the plate has interleaved fingers disposed on the diaphragm. The piezoelectric plate and the BOX layer are removed from a least a portion of the surface area of the device to provide lower thermal resistance between the conductor pattern and the substrate.

Abstract: A surface acoustic wave device comprising a base substrate, a piezoelectric layer and an electrode layer in between the piezoelectric layer and the base substrate, a comb electrode formed on the piezoelectric layer comprising a plurality of electrode means with a pitch p, defined asp=A, with A being the wavelength of the standing acoustic wave generated by applying opposite potentials to the electrode layer and comb electrode, wherein the piezoelectric layer comprises at least one region located in between the electrode means, in which at least one physical parameter is different compared to the region underneath the electrode means or fingers. A method of fabrication for such surface acoustic wave device is also disclosed. The physical parameter may be thickness, elasticity, doping concentration of Ti or number of protons obtained by proton exchange.

Abstract: Acoustic resonator devices, filter devices, and methods of fabrication are disclosed. An acoustic resonator includes a substrate having a surface and a single-crystal piezoelectric plate having front and back surfaces. The back surface is attached to the surface of the substrate except for a portion of the piezoelectric plate forming a diaphragm that spans a cavity in the substrate. An interdigital transducer (IDT) is formed on the front surface of the single-crystal piezoelectric plate such that interleaved fingers of the IDT are disposed on the diaphragm. The IDT is configured to excite a primary acoustic mode in the diaphragm in response to a radio frequency signal applied to the IDT. At least a portion of an edge of the diaphragm is at an oblique angle to the fingers.

Abstract: A method for fabricating a surface acoustic wave (SAW) device includes forming an interdigital transducer (IDT) having lead-out portions and arrays of interdigital electrodes on a substrate, wherein the interdigital electrodes include central portions, end portions, and intermediate portions between the end portions and the lead-out portions; forming a protective layer on the IDT; forming a first temperature compensation layer on the protective layer; forming openings in the first temperature compensation layer to expose portions of the protective layer on the central portions and the intermediate portions of the interdigital electrodes; and etching the exposed portions of the protective layer, and etching the central portions and the intermediate portions of the interdigital electrodes to a preset thickness, to form protruding structures at the end portions of the interdigital electrodes.

Abstract: Certain aspects of the present disclosure provide a surface acoustic wave (SAW) resonator with piston mode design and electrostatic discharge (ESD) protections. An example electroacoustic device generally includes a piezoelectric material and a first electrode structure disposed above the piezoelectric material. The first electrode structure comprises first electrode fingers arranged within an active region having a first region and a second region. At least one of the first electrode fingers has at least one of a different width or a different height in the first region than in the second region, and the first electrode fingers comprise a first electrode finger that has a width or height in the second region that is less than a corresponding width or height of the at least one of the first electrode fingers in the second region.

Abstract: A filter cable, which solves the problem that devices which can better cope with various problems in complex electromagnetic environment and have simple and reasonable structural design are lacking in the related art. The filter cable comprises a core wire; the core wire comprises an insulating substrate and a first conductor layer surrounding the insulating substrate; the first conductor layer has a first etching pattern; the first etching pattern is distributed along the axial direction of the filter cable; and the first etching pattern is used to make the filter cable equivalent to a first filter circuit to realize the filtering function.

Abstract: An apparatus and method for a frequency based integrated circuit that selectively filters out unwanted bands or regions of interfering frequencies utilizing one or more tunable notch or bandpass filters or tunable low or high pass filters capable of operating across multiple frequencies and multiple bands in noisy RF environments. The tunable filters are fabricated within the same integrated circuit package as the associated frequency based circuitry, thus minimizing R, L, and C parasitic values, and also allowing residual and other parasitic impedance in the associated circuitry and IC package to be absorbed and compensated.

Abstract: An inductor device includes a first trace, a second trace, a first capacitor, and at least one connection element. The first trace includes at least two sub-traces. One terminal of the at least two sub-traces is coupled to a first node. The second trace includes at least two sub-traces. One terminal of the at least two sub-traces is coupled to a second node. The first capacitor is coupled between the first node and the second node. The at least one connection element is coupled to another terminal of the at least two sub-traces of the first trace and another terminal of the at least two sub-traces of the second trace, such that the first trace and the second trace form a closed loop.

Abstract: A tunable filter with wide tuning range and high out-of-band rejection is achieved with a tunable bandpass filter and a number of cascaded, fixed frequency Lame-Mode Resonators (LMRs) notch filters or other resonators. In some embodiments, the filter can be implemented with all of the elements on an integrated circuit, saving space for use in applications such as mobile phones or other mobile communication devices.

Abstract: Embodiments of this disclosure relate to reducing coupling between acoustic wave resonators. An isolation region of a substrate can be located between acoustic wave resonators. The isolation region can reduce capacitive coupling through the substrate between the acoustic wave resonators. In certain embodiments, the isolation region can be located between acoustic wave resonators of different filters to thereby increase isolation between the filters.

Abstract: Methods of making packaged surface acoustic wave devices are provided. The method may include forming a photosensitive resin coat over a cavity-defining structure encapsulating a surface acoustic wave device. The photosensitive resin coat may be formed using a spin-coating process, and then patterned to form a desired shape. Portions of the photosensitive resin may be removed from areas near the edge of the die, to facilitate separation of a wafer into individual dies. The method may also include forming a conductive structure using a plating process, where the conductive structure is located between the resin coat and the cavity defining structure. The photosensitive resin can include a phenol resin. The packaged surface acoustic wave devices made using a photosensitive resin coat may be relatively thin, and may have a height of less than 220 micrometers.

Abstract: An acoustic wave device includes a support substrate, a piezoelectric layer provided over the support substrate, comb-shaped electrodes disposed on the piezoelectric layer, each of the comb-shaped electrodes including electrode fingers exciting an acoustic wave, a temperature compensation film interposed between the support substrate and the piezoelectric layer and having a temperature coefficient of an elastic constant opposite in sign to that of the piezoelectric layer, a boundary layer interposed between the support substrate and the temperature compensation film, an acoustic velocity of a bulk wave propagating through the boundary layer being higher than an acoustic velocity of a bulk wave propagating through the temperature compensation film and being lower than an acoustic velocity of a bulk wave propagating through the support substrate, and an intermediate layer interposed between the support substrate and the boundary layer and having a Q factor less than a Q factor of the boundary layer.

Abstract: Band N77 bandpass filters include a first plurality of transversely-excited film bulk acoustic resonators (XBARs) on a first chip comprising a first rotated YX-cut lithium niobate piezoelectric plate having a thickness less than or equal to 535 nm, and a second plurality of XBARs on a second chip comprising a second rotated YX-cut lithium niobate piezoelectric plate having a thickness greater than or equal to 556 nm. A circuit card is coupled to the first chip and the second chip. The circuit card includes conductors for making electrical connections between the first chip and the second chip.

Abstract: Acoustic resonators and filter devices, and methods for making acoustic resonators and filter devices. An acoustic resonator includes a substrate having a surface and a single-crystal piezoelectric plate having front and back surfaces. The back surface is attached to the surface of the substrate except for a portion of the piezoelectric plate forming a diaphragm spanning a cavity in the substrate. A conductor pattern formed is formed on the front surface of the piezoelectric plate, including an interdigital transducer (IDT) with interleaved fingers of the IDT on the diaphragm. An insulating layer is formed between the piezoelectric plate and portions of the conductor pattern other than the interleaved fingers.

Abstract: Certain aspects of the present disclosure provide a filter circuit and techniques for filtering using the filter circuit. The filter circuit generally includes a first filter stage having a first acoustic wave resonator coupled in a series path between a first port of the filter circuit and a second port of the filter circuit, a first inductor-capacitor (LC) tank circuit, a first capacitor coupled between a first terminal of the first acoustic wave resonator and the first LC tank circuit, the first LC tank circuit being coupled between the first capacitor and a reference potential node, and a second capacitor coupled between a second terminal of the first acoustic wave resonator and the first LC tank circuit. In some aspects, the filter circuit includes one or more other filter stages coupled to the first filter stage.

Abstract: An electromagnetic field band-stop filter includes a plurality of unit structures that have reflection characteristics on an electromagnetic wave of a predetermined frequency. Each of the plurality of unit structures includes: a plurality of electrode parts each of which is disposed along a side of a polygon in a non-contact manner with another electrode part; and a plurality of conductor parts which are provided for the plurality of electrode parts on a one-to-one basis and each of which has at least one bent portion between one end and other end, the one ends of the plurality of conductor parts being connected to the electrode parts on a one-to-one basis and the other ends of the plurality of conductor parts being connected at one point on an inner side of the electrode parts in the individual unit structure.

Abstract: Aspects of this disclosure relate to a band pass filter that includes LC resonant circuits coupled to each other by a capacitor. A bridge capacitor can be in parallel with series capacitors, in which the series capacitors include the capacitor coupled between the LC resonant circuits. The bridge capacitor can create a transmission zero at a frequency below the passband of the band pass filter. The LC resonant circuits can each include a surface mount capacitor and a conductive trace of the substrate, and an integrated passive device die can include the capacitor. Band pass filters disclosed herein can be relatively compact, provide relatively good out-of-band rejection, and relatively low loss.

Abstract: Surface acoustic wave devices and related methods. In some embodiments, a surface acoustic wave device for providing resonance of a surface acoustic wave having a wavelength ? can include a quartz substrate and a piezoelectric plate formed from LiTaO3 or LiNbO3 disposed over the quartz substrate. The piezoelectric plate can have a thickness greater than 2?. The surface acoustic wave device can further include an interdigital transducer electrode formed over the piezoelectric plate. The interdigital transducer electrode can have a mass density ? in a range 1.50 g/cm3<??6.00 g/cm3, 6.00 g/cm3<??12.0 g/cm3, or 12.0 g/cm3<??23.0 g/cm3, and a thickness greater than 0.148?, greater than 0.079?, or greater than 0.036?, respectively.

Abstract: Devices and methods related to film bulk acoustic resonators. In some embodiments, a film bulk acoustic resonator can be manufactured by a method that includes forming a first electrode having a first lateral shape and providing a piezoelectric layer on the first electrode. The method can further include forming a second electrode having a second lateral shape on the piezoelectric layer such that the piezoelectric layer is between the first and second electrodes. The forming of the first electrode and the forming of the second electrode can include selecting and arranging the first and second lateral shapes to provide a resonator shape defined by an outline of an overlap of the first and second electrodes, such that the resonator shape includes N curved sections joined by N vertices of an N-sided polygon, and such that the resonator shape has no axis of symmetry.