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.
摘要:
A surface acoustic wave filter including a piezoelectric substrate, an exciting electrode formed on the piezoelectric substrate and exciting a surface acoustic wave, and a receiving electrode receiving the surface acoustic wave. Both the exciting and receiving electrodes are provided with interdigital electrode fingers having a period p. One of the exciting and receiving electrodes is constructed of a plurality of interdigital electrode sub-units having substantially the same electrode surface areas occupied by interdigital electrode fingers. The interdigital electrode sub-units are disposed in a direction perpendicular to a propagation direction of the excited surface acoustic wave and have a positional relation such that the interdigital electrode sub-units are offset from each other by (n±¼)p, wherein n is an integer, in a direction parallel to the propagation direction of the surface acoustic wave.
摘要:
A surface acoustic wave filter includes a piezoelectric substrate, input and output IDTs, and first and second direction changing electrodes, wherein at least one of the input and output IDTs includes a weighted interdigital transducer, the input and output IDTS being arranged in a direction perpendicular to a propagation direction of a surface acoustic wave (SAW) oscillated by the input IDT. The first direction changing electrode changes the propagation direction of the SAW, which has propagated in a left directed from the input IDT, into a direction towards the output IDT. The second direction changing electrode changes the propagation direction of the SAW, which has propagated in a right direction from the input IDT, into a direction towards the output IDTs and the first and second direction changing electrodes is set for obtaining at the output IDT the SAW having desired frequency characteristics.
摘要:
The multimode surface acoustic wave filter includes two surface acoustic wave resonators closely arranged on a piezoelectric substrate in a direction perpendicular to the propagation direction of surface acoustic waves and acoustically coupled by a coupling section, each of the surface acoustic wave resonators including an interdigital transducer and two reflectors disposed closely on both sides of the interdigital transducer in a direction parallel to the propagation direction of the surface acoustic waves, the interdigital transducer having an excitation section for exciting the surface acoustic waves and a signal terminal section for inputting an electric signal, each of the reflectors having a grating section and a terminal section, wherein the velocity of surface acoustic waves propagating through the coupling section is a little larger than the velocity of the surface acoustic waves propagating through the excitation section of the interdigital transducer.
摘要:
A surface acoustic wave filter of multi-stage connection type including a plurality of surface acoustic wave filters formed on a piezoelectric substrate and a connection section for electrically connecting the surface acoustic wave filters in a cascade connection. Each of the surface acoustic wave filters includes interdigital transducers with two signal terminals for electric input and output, each interdigital transducer including an excitation section for exciting a surface acoustic wave and two terminal sections disposed on opposite sides of the excitation section, the two terminal sections serving as input or output terminal for electric signal and ground terminal. One of the signal terminal sections is connected to the connection section, and an electrode area of said one of the signal terminal sections is adjusted so that a parasitic capacitance formed between said one of the signal terminal sections and a grounding point of the surface acoustic wave filter is less than or equal to 0.01 pF.
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.