In an arrangement having a DMS filter, it is provided to symmetrically divide at least one of the transducers (W) of the DMS filter (DMS) into two sub-transducers (T,T′) electrically connected in parallel and to shift them apart from each other by an amount of at least a half wavelength. This results in the signals of the two sub-transducers canceling each other out at a frequency in a stopband and thereby generating an attenuation pole in the upper blocking region.

A filter device includes a first filter and a second filter. The first filter and the second filter are disposed in parallel between a first terminal and a second terminal. A first passband of the filter device includes at least part of a second passband of the first filter. The first passband includes at least part of a third passband of the second filter. The second passband is narrower than the first passband. The third passband is narrower than the first passband. The third passband has a center frequency higher than a center frequency of the second passband. The first filter includes multiple elastic wave resonators and a first capacitive element. The first capacitive element is connected in parallel with the first elastic wave resonator.

An electroacoustic resonator (EAR) that allows RF filters in which transversal modes are suppressed in a wider frequency range and corresponding RF filters and methods are provided. The resonator has an electrode structure (BB,EF) on a piezoelectric material and a transversal acoustic wave guide. The wave guide has a central excitation area (CEA), trap stripes (TP) and barrier stripes (B). The difference in wave velocity (|VCEA−VB|) between the central excitation area and the barrier stripes determines the frequency range of suppressed transversal modes.

The present invention discloses a type of ultra-wide band SAW filter which comprises a first SAW resonator group and a second SAW resonator group that are connected to form a ladder structure. Each SAW resonator in the said first SAW resonator group has the same film thickness; each SAW resonator in the said second SAW resonator group has the same film thickness; the film thickness of each SAW resonator in the said first SAW resonator group is the same as or different from the film thickness of each SAW resonator in the said second SAW resonator group. The SAW filter according to the present invention can realize the pass-band non-parasitic mode response and is a high-performance ultra-wide band filter with a bandwidth of 6-20% of the center frequency and an insertion loss of less than 2 dB, and the present invention features small size, low cost and a broad application prospect in the field of military and civilian communications equipment.

An acoustic wave element of the present invention includes a substrate; and an IDT electrode on an upper surface of the substrate, including a first bus bar, a second bus bar arranged with a space in a first direction from the first bus bar, a plurality of first electrode fingers connected to the first bus bar, a plurality of second electrode fingers connected to the second bus bar, and a second dummy electrode finger facing a tip end of one of the first electrode fingers through a gap. In at least one of the second electrode fingers, a width in a region on the side closer to the second bus bar than a first virtual line connecting the tip ends of the plurality of first electrode fingers is wider than a width in a region on the side closer to the first bus bar than the first virtual line.

A filter device according to an embodiment of the present disclosure includes a first filter and a second filter that are connected in parallel between a first terminal and a second terminal. The first filter includes multiple series arm resonators. The series arm resonators are disposed in series in a path from the first terminal via the first filter to the second terminal. The series arm resonators include a first series arm resonator and a second series arm resonator. Under a condition that a value obtained by dividing a difference between an antiresonance frequency and a resonance frequency of each series arm resonator by the resonance frequency is defined as a fractional bandwidth, a first fractional bandwidth of the first series arm resonator is different from a second fractional bandwidth of the second series arm resonator.

A filter device includes a first filter and a second filter. The first filter and the second filter are disposed in parallel between a first terminal and a second terminal. A first passband of the filter device includes at least part of a second passband of the first filter. The first passband includes at least part of a third passband of the second filter. The second passband is narrower than the first passband. The third passband is narrower than the first passband. The third passband has a center frequency higher than a center frequency of the second passband. The first filter includes multiple elastic wave resonators and a first capacitive element. The first capacitive element is connected in parallel with the first elastic wave resonator.

A filter arrangement with a large bandwidth is specified, wherein a first and a second filter are connected in parallel between a first and a second node. Both filters are configured as DMS filters and both comprise two DMS tracks each, connected in series. The two filters have different center frequencies and create a common passband together.

An amplifying radiofrequency device includes a piezoelectric film and a semiconductor amplifier layer. The piezoelectric film is conformed as an acoustic waveguide. The piezoelectric film has a principal acoustic propagation direction parallel to the principal conduction direction of the amplifier layer. Interdigitated transducers are positioned on the piezoelectric film to respectively launch an acoustic wave in response to an input RF signal, and transduce the acoustic wave back to an output RF signal. There is a distance of less than the acoustic wavelength between the semiconductor amplifier layer and the piezoelectric film. The piezoelectric film has a thickness of less than the acoustic wavelength. According to a method for making such a device, a stack of III-V layers is epitaxially grown on a III-V substrate, wherein the stack comprises a first etch stop layer, a second etch stop layer, an amplifier layer, and a contact layer. The stack is bonded to a lithium niobate film. The III-V substrate is removed by etching down to the first etch stop layer. Deposition windows are opened by etching from the first etch stop layer down to the contact layer. Metal contact electrodes are deposited in the deposition windows.

A filter including a piezoelectric substrate; a surface acoustic wave (SAW) device on the piezoelectric substrate and including unequally spaced interdigitated input and output transducer electrodes of unequal widths, wherein the input transducer electrodes are to convert an incoming radio frequency (RF) electrical signal into surface acoustic waves; a SAW propagation path between the input and output transducer electrodes; and a magnetostrictive film in the SAW propagation path to filter the surface acoustic waves that are at a ferromagnetic resonance frequency of the magnetostrictive film, wherein the output transducer electrodes are to convert the filtered surface acoustic waves into an outgoing electrical RF signal. The SAW device may operate in a wide-band pass configuration. The wide-band pass configuration result in a transmission of frequencies up to 60 dB. The magnetostrictive film may include a ferromagnetic material. The interdigitated input and output transducer electrodes may include unequal widths between adjacent electrodes.