摘要:
A surface acoustic wave resonator includes a piezoelectric substrate, and a SAW resonator having an interdigital transducer. The interdigital transducer satisfies 0.15L≦W≦0.45L where W is the total of widths of all electrode fingers that form the interdigital transducer, and L is a length of the said interdigital transducer in a direction of SAW propagation.
摘要翻译:声表面波谐振器包括压电基片和具有叉指式换能器的SAW谐振器。 叉指换能器满足0.15L <= W <= 0.45L,其中W是形成叉指换能器的所有电极指的总宽度,L是所述叉指换能器在SAW传播方向上的长度。
摘要:
A surface acoustic wave resonator including at least one interdigital transducer formed on a piezoelectric substrate, wherein the at least one interdigital transducer includes a predetermined number of interdigitated electrode fingers, at least two electrode fingers among the interdigitated electrode fingers are withdrawn, and the positions of the withdrawal electrode fingers are aperiodic.
摘要:
A surface acoustic wave filter has, on a piezoelectric substrate, surface acoustic wave resonators each composed of an interdigital transducer and reflectors disposed on both sides of the interdigital transducer. The surface acoustic wave resonators are arranged in series arms and in parallel arms to be connected in a ladder form. At least one of the surface acoustic wave resonators is replaced with an interdigital transducer that does not involve resonance in a propagation direction of a surface acoustic wave.
摘要:
A surface acoustic wave filter includes a piezoelectric substrate having formed thereon plural surface acoustic wave resonators electrically connected in a ladder form for exciting a surface acoustic wave, wherein each of the surface acoustic wave resonators is composed of an interdigital transducer and reflectors arranged closely on both sides of the transducer in a direction parallel to a propagation direction of the excited surface acoustic wave; the interdigital transducer of at least one of the surface acoustic wave resonators is composed of a prescribed number of pairs of comb form electrodes; and the surface acoustic wave excited by the pairs of comb form electrodes contains two kinds of surface acoustic waves having phases that are different from each other by 180°.
摘要:
A surface acoustic wave resonator includes a piezoelectric substrate having formed thereon a interdigital transducer part comprising plural electrode fingers having a period pi that is substantially equal to a wavelength of a surface acoustic wave to be excited, and at least one reflector arranged in the vicinity of the interdigital transducer part to reflect the surface acoustic wave excited by the interdigital transducer part in a direction parallel to a propagation direction of the surface acoustic wave. The interdigital transducer part has three or more electrode fingers within the period pi, and the reflector has plural gratings having a period pr that is equal to a half of a wavelength of a surface acoustic wave propagating in the reflector.
摘要:
A duplexer includes two surface acoustic wave filter having different band center frequencies, and a phase matching circuit that matches the phases of the two surface acoustic wave filters to each other. In this duplexer, one of the two surface acoustic wave filters is a ladder type surface acoustic wave filter, while the other one of the two surface acoustic wave filters includes two or more dual-mode type surface acoustic wave filters that are connected in parallel.
摘要:
A surface acoustic wave reflector includes a piezoelectric substrate and a plurality of perturbation members arranged at a first period on the piezoelectric substrate. A plurality of free-surface regions where no perturbation members exist are formed in an arrangement of the perturbation members.
摘要:
A surface acoustic wave device includes a piezoelectric substrate and plural IDTs for sending and receiving SAW mounted on the substrate. At least one of the IDTs includes a positive electrode including plural positive split electrodes (PSEs) and a negative electrode including plural negative split electrodes (NSEs). The PSEs and NSEs are arranged alternately. Each of the PSEs andNSEs has apair of electrode fingers. Two electrode fingers of each of the split electrodes are different in width in a direction in which a SAW is excited. An angle .alpha. determined by a direction transverse to the electrode fingers from one of the two electrode fingers having a smaller reflection factor toward the other one having a larger reflection factor and a direction in which the SAW excited by the IDT including the split electrodes travels to one of the IDTs for receiving the SAW is equal to or larger than 0.degree. and smaller than 90.degree., i.e., 0.ltoreq..alpha.
摘要:
A surface acoustic wave device includes a plurality of surface acoustic wave filter chips having external connection terminals and a package accommodating the plural surface acoustic wave filter chips. The package is provided with a plurality of terminals for connection with the surface acoustic wave filter chips, and one of the external connection terminals of a first one of the surface acoustic wave filter chips is connected with one of the terminals of the package via a second one of the surface acoustic wave filter chips.
摘要:
The present invention relates to a surface acoustic wave filter which is characterized in that it includes a piezoelectric substrate, a plurality of surface acoustic wave propagation paths arranged in parallel on the piezoelectric substrate and a coupler for coupling the surface acoustic wave propagation paths, an input interdigital transducer and a first reflector are disposed on at least one of the surface acoustic wave propagation paths with intervention of the coupler, and an output interdigital transducer and a second reflector are disposed on at least one of the other surface acoustic wave propagation paths with intervention of the coupler. This construction can reduce the length of the surface acoustic wave filter in a surface acoustic wave propagation direction and can improve the shape factor of a frequency characteristic curve.