摘要:
An elastic wave filter device having improved sharpness of filter characteristics includes a longitudinally-coupled resonator-type elastic wave filter section including first to third IDT electrodes each including a plurality of electrode fingers, and first and second reflectors. The first to third IDT electrodes include narrower-pitch portions provided in end portions thereof, which are each adjacent to another IDT electrode in a direction of propagation of elastic waves, each of the narrower-pitch portions having a smaller period of electrode fingers than a period of electrode fingers in the remaining portion of the relevant IDT electrode. The number of electrode fingers in the narrower-pitch portion of the second IDT electrode, which is disposed on the side closer to the first IDT electrode, and the number of electrode fingers in the narrower-pitch portion of the second IDT electrode, which is disposed on the side closer to the third IDT electrode, differ from each other.
摘要:
An elastic wave device includes an unbalanced terminal and first and second balanced terminals. A longitudinally-coupled-resonator-type first elastic wave filter is provided between the unbalanced terminal and the first balanced terminal. An elastic wave filter, which is connected in parallel with the first elastic wave filter, is connected between the unbalanced terminal and the second balanced terminal. The current paths through which IDT electrodes of the elastic wave filters of the elastic wave device are connected to ground terminals, are not symmetrical.
摘要:
An elastic wave device includes an unbalanced terminal and first and second balanced terminals. A longitudinally-coupled-resonator-type first elastic wave filter is provided between the unbalanced terminal and the first balanced terminal. An elastic wave filter, which is connected in parallel with the first elastic wave filter, is connected between the unbalanced terminal and the second balanced terminal. The current paths through which IDT electrodes of the elastic wave filter and the elastic wave filter are connected to ground terminals, are not symmetrical.
摘要:
An elastic wave apparatus includes a balanced-unbalanced transforming function, and an elastic wave filter and a multilayer wiring board on which the elastic wave filter is mounted. The elastic wave filter includes an unbalanced terminal and first and second balanced terminals. External electrodes used are provided on the multilayer wiring board. A first internal line connects the first balanced terminal and the external electrode. A second internal line connects the second balanced terminal and the external electrode. The lengths or shapes of the first internal line and the second internal line are set so that a capacitance used for the improvement of a balance is generated in an adjacent area A where the first internal line and the second internal line are adjacent to each other. In the adjacent area A, the directions of currents passing through the first internal line and the second internal line are the same.
摘要:
An acoustic wave filter device includes first to fourth longitudinally coupled resonator type surface acoustic wave filters that are configured such that the first and second filters are connected to a first balanced signal terminal, the third and fourth filters are connected to a second balanced signal terminal, and a transmission phase of a signal output from the first balanced signal terminal relative to an input signal differs by about 180 degrees with respect to a transmission phase of a signal output from the second balanced signal terminal relative to an input signal. In addition, the number of pairs of electrode fingers of at least one of IDTs of at least one of the first to fourth longitudinally coupled resonator type surface acoustic wave filters is different from the number of pairs of electrode fingers of corresponding IDTs of the remaining first to fourth filters.
摘要:
A piezoelectric device includes a piezoelectric substrate, a conductive pattern which is provided on one main surface of the piezoelectric substrate and which includes an IDT electrode, a supporting layer which is arranged on the one main surface of the piezoelectric substrate so as to surround the periphery of an IDT-forming region in which the IDT electrode is provided and which has a thickness greater than that of the IDT electrode, and a cover layer which is arranged on the supporting layer and which covers the IDT-forming region. The supporting layer includes removed sections provided at a plurality of positions at least in a region close to the IDT-forming region, the removed sections being obtained by partially removing a portion of the supporting layer to be bonded to the one main surface of the piezoelectric substrate.
摘要:
A duplexer includes a transmission filter having a ladder circuit configuration and a reception filter. The reception filter includes an input terminal connected to an antenna terminal, a first reception output terminal, and a second reception output terminal. A first filter element and a second filter element, each of which is a longitudinally coupled resonator filter element including a plurality of IDTs, are connected in parallel to the input terminal so that IDTs are connected to the input terminal. The first filter element the second filter element are connected to the first reception output terminal and the second reception output terminal, respectively.
摘要:
In an acoustic wave filter device, first and second longitudinally coupled resonator SAW filters are provided on a piezoelectric substrate. The first and second longitudinally coupled resonator SAW filters are connected in parallel to each other. The first and second longitudinally coupled resonator SAW filters are withdrawal-weighted. The withdrawal weighting in at least the longitudinally coupled resonator SAW filter is different from the withdrawal weighting in the other longitudinally coupled resonator SAW filter.
摘要:
A surface acoustic wave device includes a substrate, a plurality of terminals including at least an unbalanced terminal and balanced terminals, and at least one of surface acoustic wave element disposed between the unbalanced terminal and the two balanced terminals. Different signal lines connected to the same surface acoustic wave element intersect through insulating films.
摘要:
In a longitudinally-coupled-resonator surface acoustic wave filter unit having a first interdigital transducer, a central interdigital transducer, a second interdigital transducer, and first and second reflectors arranged such that the interdigital transducers are provided therebetween, for one comb electrode of the central interdigital transducer, first and second comb electrodes, which are substantially symmetrically bisected along a surface-acoustic-wave propagation direction, are provided. Between the first and second comb electrodes, a design parameter of at least one of the interdigital transducers, and the reflectors is set to be different from one another.