摘要:
A piezoelectric thin-film resonator includes a lower electrode provided on a substrate, a piezoelectric thin film provided on the lower electrode, and an upper electrode provided on the piezoelectric thin film. A membrane region is defined by a region where the upper electrode and the lower electrode overlap each other to sandwich the piezoelectric thin film therebetween and has an elliptical shape, and the lower electrode is also provided at an outer side of the membrane region in a region in which neither an extraction electrode of the upper electrode nor an extraction electrode of the lower electrode is provided.
摘要:
A duplexer includes a transmission filter and a reception filter having different passbands, wherein: first resonators that are series resonators or parallel resonators included in the transmission and reception filters so as to form a skirt characteristic at a guard band side are a temperature compensated type piezoelectric thin film resonator or a surface acoustic wave resonator using Love waves, and second resonators that form a skirt characteristic at an opposite side to the guard band are one of a temperature non-compensated type piezoelectric thin film resonator, a surface acoustic wave resonator using a lithium tantalate substrate or a substrate made by bonding a lithium tantalate substrate on a sapphire substrate, and a surface acoustic wave resonator using Love waves.
摘要:
A method of manufacturing an elastic wave device is provided with a lamination step of forming, on a substrate (1), a plurality of elastic wave devices, each of which includes a lower electrode (2), a piezoelectric film (3), and an upper electrode (4); a measuring step for measuring the operation frequency distribution of the elastic wave devices on the substrate (1); and an adjusting step for forming an adjusting region, in which the thickness of the elastic wave device is different from the thicknesses of other portions in a resonance portion of each elastic wave device, corresponding with the distribution of the operation frequencies. The adjusting region is formed so that the size of the area of the adjusting region of the resonator portion of each elastic wave device is different in accordance with the operation frequency distribution that is measured. Thus, the frequency characteristics of the elastic wave devices are easily adjusted by a small number of steps.
摘要:
An acoustic wave device includes a substrate and a plurality of piezoelectric thin film resonators formed over the substrate. Each of the plurality of the piezoelectric thin film resonators includes lower electrode provided on the substrate, a piezoelectric film provided on the lower electrode, and an upper electrode provided on the piezoelectric film and opposed to the lower electrode through the piezoelectric film. Each of the piezoelectric thin film resonators is partly supported by the substrate and extends above the substrate to form a cavity between the substrate and each lower electrodes. The cavity continuously extending under the plurality of the piezoelectric thin film resonators.
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 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 ladder type filter includes series resonators S1˜S4 connected in series between an input terminal In and an output terminal Out, parallel resonators P1˜P3 connected in parallel between the input terminal In and the output terminal Out, a resonator RP connected in series with the series resonators S1˜S4 between the input terminal and the output terminal, the resonator RP having a resonance frequency lower than resonance frequencies of the series resonators S1˜S4, and an inductor Lp connected in parallel with the resonator. According to the present ladder filter, signals having frequencies away from the pass band can be suppressed by an attenuation pole formed by the inductor. It is further possible to suppress the insertion loss in the pass band by the resonator.
摘要:
An acoustic wave device includes a first resonator having a piezoelectric substance sandwiched between a pair of electrodes in a direction of an c-axis orientation or a polarization axis, and a second resonator that is connected in series and has another piezoelectric substance sandwiched another pair of electrodes so that one of the another pair of electrodes located in the direction of the c-axis orientation or the polarization axis is at a potential equal to that of one of the pair of electrodes of the first resonator in the direction of the c-axis orientation or the polarization axis.
摘要:
An antenna duplexer is provided, which can be built with a smaller size and lower height than ever without compromising out-of-band attenuation characteristic and isolation characteristic between a transmit terminal and a receive terminal. The antenna duplexer includes a transmit filter provided between an antenna terminal and the transmit terminal, and a receive filter provided between the antenna terminal and the receive terminal. The filters are enclosed by a package, in which a ground pattern for the receive filter is separated from other ground patterns.
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 provided on the piezoelectric film. At least a portion of the upper electrode and that of the lower electrode oppose each other through the piezoelectric film, and at least a portion of the periphery of the upper electrode is reversely tapered.