摘要:
A ladder filter includes a series resonator having a first film laminate in which an upper electrode and a lower electrode face each other across a piezoelectric film, and a first film provided on the first film laminate, and a parallel resonator having a second film laminate having a structure similar to that of the first film laminate, a second film provided on the second film laminate, and another first film identical to the first film.
摘要:
The filter includes a series arm piezoelectric thin film resonator placed in the series arm and a parallel arm piezoelectric thin film resonator placed in the parallel arm. Each of the series arm piezoelectric thin film resonator and the parallel arm piezoelectric thin film resonator includes a substrate (21), a lower electrode (22) placed on the substrate (21), a piezoelectric film (23) placed on the lower electrode (22) and a upper electrode (24) placed on the piezoelectric film (23). The ratio of the major axis length A to the minor axis length B of the resonant portion (29) in the series arm piezoelectric thin film resonator is larger than that in the parallel arm piezoelectric thin film resonator.
摘要:
A piezoelectric thin film resonator includes a substrate, a lower electrode formed on the substrate, a piezoelectric film formed on the substrate and the lower electrode, and an upper electrode formed on the piezoelectric film and opposing the lower electrode, an upper electrode formed on the piezoelectric film. The upper electrode has a main portion and an extended portion connected to the main portion, the main portion opposing the lower electrode and an opening disposed between the substrate and the lower electrode, the extended portion having a portion which opposes the opening and the substrate.
摘要:
A filter has a plurality of piezoelectric thin film resonators formed by sandwiching a piezoelectric film with a lower electrode disposed on a substrate and an upper electrode. Each of the piezoelectric thin film resonators has an electrode region formed with the upper electrode and the lower electrode overlapping each other, whose outline includes a curve. Among the plural piezoelectric thin film resonators, the piezoelectric thin film resonators in the opposing electrode regions of the adjacent piezoelectric thin film resonators are shaped to have outlines complementary to each other. With the filter, influences caused by transverse mode undesired wave of the piezoelectric thin film resonators can be suppressed. Therefore, miniaturization can be achieved without sacrificing the mechanical strength of electrodes having hollow structures.
摘要:
A filter element includes a plurality of multilayer filters that are connected in cascade, each of the plurality of multilayer filters including a plurality of piezoelectric thin-film resonators stacked vertically, each of the piezoelectric thin-film resonators including a piezoelectric film and a pair of first electrodes between which the piezoelectric film is interposed, and a capacitor connected between an input terminal of one of the plurality of multilayer filters of a preceding stage and an input terminal of another one of the plurality of multilayer filters of a following stage, exciting directions of piezoelectric thin-film resonators to which the input terminals of the multilayer filters of the preceding and following stages are connected being opposite to each other.
摘要:
A piezoelectric thin-film resonator includes a substrate, a lower electrode provided on the substrate, a piezoelectric film provided on the substrate and the lower electrode, an upper electrode provided on the piezoelectric film, and an additional pattern, a cavity being formed between the lower electrode and the substrate in a resonance portion in which the lower electrode and the upper electrode face each other through the piezoelectric film, the additional pattern being provided in a position that is on the lower electrode and includes an interface between the resonance portion and a non-resonance portion.
摘要:
A filter includes: a first filter unit includes: a series resonators connected in series to each other between a first input terminal and a first output terminal; a parallel resonators each having one end connected to one terminal of each of the series resonators; and a common inductance having one end connected to the other ends of the parallel resonators and the other end connected to a ground terminal, and a second filter unit includes: a series resonators connected in series to each other between a second input terminal and a second output terminal; a parallel resonators each having one end connected to one terminal of each of the series resonators; and a common inductance having one end connected to the other ends of the parallel resonators and the other end connected to the ground terminal.
摘要:
An electronic circuit includes a plurality of duplexers that are coupled to an antenna terminal and have a pass band different from each other and a plurality of acoustic wave filters that are respectively coupled between the antenna terminal and the plurality of the duplexers, wherein filter characteristics of a first acoustic wave filter of the plurality of the acoustic wave filters are set so as to allow passage of a signal in both a pass band for transmitting and a pass band for receiving of a first duplexer of the plurality of the duplexers that is coupled to the first acoustic wave filter and suppress passage of a signal in both a pass band for transmitting and a pass band for receiving of a second duplexer of the plurality of the duplexers that is different from the first duplexer.
摘要:
A piezoelectric thin-film resonator includes a substrate, a lower electrode provided on the substrate, a piezoelectric film provided on the lower electrode and an upper electrode that is located opposite the lower electrode across at least a part of the piezoelectric film. A mass load film is provided on the upper electrode. The mass load film includes a plurality of concave or convex patterns in at least a region that faces the lower electrode. The plurality of concave or convex patterns are densely arranged in a central portion of the region and are sparsely arranged in a peripheral portion of the region.
摘要:
An acoustic wave device includes a main resonator and a sub resonator each having a substrate, a lower electrode provided on the substrate, a piezoelectric film provided on the lower electrode, and an upper electrode provided on an upper side of the piezoelectric film. A frequency control film is provided on an upper side of a resonance area in which the upper electrode and the lower electrode face each other in at least one of the main resonator and the sub resonator. The frequency control film has multiple convex patterns, and the convex patterns are arranged with a common pitch for spurious adjustment and with different areas in the main resonator and the sub resonator.