Abstract: An acoustic wave element of the present disclosures has a piezoelectric substrate and an acoustic wave resonator S1 on a main surface of the piezoelectric substrate. The acoustic wave resonator S1 is one being divided into a first IDT electrode and a second IDT electrode which are electrically connected to the first IDT electrode. The first IDT electrode includes a first comb-shaped electrode on the signal input side and a second comb-shaped electrode on the signal output side. The second IDT electrode includes a third comb-shaped electrode on the signal input side and a fourth comb-shaped electrode on the signal output side. The direction of arrangement of the third comb-shaped electrode and the fourth comb-shaped electrode from the third comb-shaped electrode toward the fourth comb-shaped electrode is different from the direction of arrangement from the first comb-shaped electrode toward the second comb-shaped electrode.

Abstract: SAW element has a substrate; an IDT having a first comb-shaped electrode and a second comb-shaped electrode located on an upper surface of the substrate; and a capacitance element located on the upper surface of the substrate. The capacitance element has a first counter electrode connected to the first comb-shaped electrode and a second counter electrode connected to the second comb-shaped electrode and facing the first counter electrode across a third gaps. The direction from the first counter electrode through the third gaps toward the second counter electrode is a reverse direction from the direction from the first comb-shaped electrode through the gaps toward the second comb-shaped electrode.

Abstract: The IDT electrode has the first bus bar and second bus bar; the plurality of first electrode fingers and the plurality of second electrode fingers mutually intersect; the plurality of first dummy electrodes and the plurality of second dummy electrodes which extend have front ends facing front ends of the plurality of first electrode fingers and the plurality of second electrode fingers with the gap s1; the plurality of first auxiliary electrodes which protrude laterally from the front end side portions of the pluralities of first dummy electrodes; and the plurality of second auxiliary electrodes which protrude laterally from the front end side portions of the plurality of second dummy electrodes. The plurality of first auxiliary electrodes have edge portions located a side of the second bus bar. The edge portions are located a side of the second bus bar the more to a side of the front end.

Abstract: A SAW element has a substrate; an IDT electrode located on an upper surface of the substrate and comprises Al or an alloy containing Al; a first film located on an upper surface of the IDT electrode; and a protective layer which covers the IDT electrode provided with the first film and the portion of the substrate exposed from the IDT electrode, which has a thickness from the upper surface of the substrate larger than a total thickness of the IDT electrode and first film, and which contains a silicon oxide. The first film contains a material which has a larger acoustic impedance than the material (Al or the alloy containing Al) of the IDT electrode and the silicon oxide and which has a slower propagation velocity of an acoustic wave than the material of the IDT electrode and the silicon oxide.

Abstract: The invention relates to a small and low-voltage operable dielectric waveguide device. First and second electrode are embedded in a dielectric part and are formed to be thinner than a skin depth for a frequency of electromagnetic wave propagating along a first dielectric part included in the dielectric part. Thereby, even if the first and second electrodes are arranged to be in contact with the first dielectric part, the propagating electromagnetic wave can transmit the first and second electrodes, and therefore the electromagnetic wave can propagate without being cut off and there is no influence on waveguide modes of the electromagnetic wave. Further, in a state where a transmission loss due to the embedded of the electrode is suppressed, an electric field with large electric field strength can be applied to the first dielectric part by the first and second electrodes, and a small and low-voltage operable dielectric waveguide device can be achieved.

Abstract: The invention relates to a small and low-voltage operable dielectric waveguide device. First and second electrode are embedded in a dielectric part and are formed to be thinner than a skin depth for a frequency of electromagnetic wave propagating along a first dielectric part included in the dielectric part. Thereby, even if the first and second electrodes are arranged to be in contact with the first dielectric part, the propagating electromagnetic wave can transmit the first and second electrodes, and therefore the electromagnetic wave can propagate without being cut off and there is no influence on waveguide modes of the electromagnetic wave. Further, in a state where a transmission loss due to the embedded of the electrode is suppressed, an electric field with large electric field strength can be applied to the first dielectric part by the first and second electrodes, and a small and low-voltage operable dielectric waveguide device can be achieved.

Abstract: A thin film capacitor includes a pair of electrodes and a dielectric layer having piezoelectricity sandwiched therebetween. The phase characteristic of an impedance resulting from application of a voltage to the pair of electrodes peaks periodically according to a frequency of a signal to be inputted or outputted. The frequency of the signal is adjusted to fall in between the values representing the adjacent peaks. Since there are periodic peak values that depend upon the frequency of the inputted or outputted signal, in fabricating a band-pass filter, a higher attenuation can be attained by ensuring that the peak value stands at a low-frequency level. Thus, a higher attenuation can be attained at low frequencies without sacrificing the band-pass characteristic, whereby making it possible to produce a band-pass filter that is excellent in band-pass characteristic.

Abstract: There is disclosed a variable capacitance circuit which comprises: first to Nth variable capacitance elements C1-CN (N is an odd number) sequentially connected in series between an input terminal I and an output terminal O, whose capacitances change depending on voltage applied thereto; an ith bias line on the input terminal side provided between an input terminal portion of the first variable capacitance element and a connection point between a 2ith variable capacitance element and a (2i+1)th variable capacitance element; and an ith bias line on the output terminal side provided between an output terminal portion of the Nth variable capacitance element and a connection point between a (2i?1)th variable capacitance element and the 2ith variable capacitance element, where N and i are integers satisfying N=2n+1, n?1, 1?i?n.

Abstract: A thin film capacitor includes a pair of electrodes and a dielectric layer having piezoelectricity sandwiched therebetween. The phase characteristic of an impedance resulting from application of a voltage to the pair of electrodes peaks periodically according to a frequency of a signal to be inputted or outputted. The frequency of the signal is adjusted to fall in between the values representing the adjacent peaks. Since there are periodic peak values that depend upon the frequency of the inputted or outputted signal, in fabricating a band-pass filter, a higher attenuation can be attained by ensuring that the peak value stands at a low-frequency level. Thus, a higher attenuation can be attained at low frequencies without sacrificing the band-pass characteristic, whereby making it possible to produce a band-pass filter that is excellent in band-pass characteristic.

Abstract: It is an object of the invention to provide a variable capacitor constituted such that, even when an external control voltage is applied, a stable dielectric constant of the dielectric layer can be obtained. A variable capacitor constituted such that a dielectric layer whose dielectric constant is changed by the application of an external voltage is held between an upper electrode layer and a lower electrode layer, wherein a plurality of capacitance-producing regions a, b are connected to each other.

Abstract: There is disclosed a variable capacitance circuit which comprises: first to Nth variable capacitance elements C1-CN (N is an odd number) sequentially connected in series between an input terminal I and an output terminal O, whose capacitances change depending on voltage applied thereto; an ith bias line on the input terminal side provided between an input terminal portion of the first variable capacitance element and a connection point between a 2ith variable capacitance element and a (2i+1)th variable capacitance element; and an ith bias line on the output terminal side provided between an output terminal portion of the Nth variable capacitance element and a connection point between a (2i−1)th variable capacitance element and the 2ith variable capacitance element, where N and i are integers satisfying N=2n+1, n≧1, 1≦i≦n.

Abstract: It is an object of the invention to provide a variable capacitor constituted such that, even when an external control voltage is applied, a stable dielectric constant of the dielectric layer can be obtained. A variable capacitor constituted such that a dielectric layer whose dielectric constant is changed by the application of an external voltage is held between an upper electrode layer and a lower electrode layer, wherein a plurality of capacitance-producing regions a, b are connected to each other.

Abstract: A non-radiative dielectric waveguide coupler for coupling or dividing high-frequency signals between at least two dielectric waveguides arranged maintaining a predetermined gap between a pair of parallel flat conductors, wherein said two dielectric waveguides are connected to each other through a bridge of a dielectric material. Upon joining the two dielectric waveguides through the bridge, the gap between the two dielectric waveguides, that affects the characteristics of the coupler, is set maintaining a high precision without effecting any particular positioning operation. Therefore, the coupler can be mass-produced very favorably. Besides, the gap between the two dielectric waveguides is stably maintained without being varied during the production of the coupler or during the use of the coupler, contributing to improving the reliability of the coupler.

Abstract: A module equipped with a non-radiative dielectric waveguide in accordance with this invention comprises a pair of parallel flat conductors arranged at a space of 1/2 or below of a high frequency signal wavelength .lambda. and a dielectric strip extending between these parallel flat conductors. This dielectric strip is formed from a cordierite ceramic having a dielectric constant of 4.5 to 8, especially 4.5 to 6. Conversion of an electromagnetic wave of LSM mode to an electromagnetic wave of LSE is minimal. When the module has a dielectric strip having a steep curved portion having a small radius of curvature, the transmission is possible with a low loss, and the band width of a high frequency signal is broad.