Abstract: A surface acoustic wave device comprises a surface acoustic wave element, including: a piezoelectric substrate, a first interdigital transducer unit having a first interdigital transducer and a second interdigital transducer formed on the piezoelectric substrate, and a second interdigital transducer unit having a third interdigital transducer and a fourth interdigital transducer formed on the piezoelectric substrate; a first terminal electrically coupled to the first interdigital transducer; a second terminal electrically coupled to the second interdigital transducer; a first variable resistor electrically coupling the first terminal to the third interdigital transducer; a second variable resistor electrically coupling the first terminal to the fourth interdigital transducer; a third variable resistor electrically coupling the second terminal to the third interdigital transducer; and a fourth variable resistor electrically coupling the second terminal to the fourth interdigital transducer.

Abstract: A longitudinally coupled multi-mode SAW resonator filter includes input and output interdigital transducers (IDTs) with a control IDT therebetween to control a state of the surface acoustic wave. The input, output, and control IDTs alternatively arrange two different zones C and E having respective electrode period lengths PC and PE, being equal to a sum of the electrode finger width L and spacing S between electrode fingers, and a number of respective pairs MC and ME of electrode fingers is set to 1 in both zones C and E. Electrode fingers in zones C and E are all connected to a feeder conductor. Hence, a filter having small insertion loss, and a wide fractional bandwidth of 2000-4000 ppm is achieved by canceling and decreasing sums of reflected waves from the electrode fingers in zones C and E, and decreasing the effective reflection coefficient per the electrode finger.

Abstract: A surface acoustic wave (SAW) resonator, including: a first interdigital transducer composed of a pair of interdigital electrodes provided in a propagation direction of a surface acoustic wave; a second interdigital transducer composed of a pair of interdigital electrodes provided in parallel to the first interdigital transducer; and a switch that alternately switches the pair of interdigital electrodes of the first interdigital transducer and the pair of interdigital electrodes of the second interdigital transducer; wherein 7??B?33? where ? is a wavelength of a surface acoustic wave, and B is an addition of a width a1 of an engaged section of electrode fingers of the first interdigital transducer, a width a2 of an engaged section of electrode fingers of the second interdigital transducer, and a distance b between the engaged sections of both interdigital transducers.

Abstract: A surface acoustic wave device comprises a surface acoustic wave element, including: a piezoelectric substrate, a first interdigital transducer unit having a first interdigital transducer and a second interdigital transducer formed on the piezoelectric substrate, and a second interdigital transducer unit having a third interdigital transducer and a fourth interdigital transducer formed on the piezoelectric substrate; a first terminal electrically coupled to the first interdigital transducer; a second terminal electrically coupled to the second interdigital transducer; a first variable resistor electrically coupling the first terminal to the third interdigital transducer; a second variable resistor electrically coupling the first terminal to the fourth interdigital transducer; a third variable resistor electrically coupling the second terminal to the third interdigital transducer; and a fourth variable resistor electrically coupling the second terminal to the fourth interdigital transducer.

Abstract: It is aimed to provide a resonator type SAW filter having a relatively wide fractional bandwidth by canceling and decreasing reflection coefficients of electrode fingers each other with a ¼ wavelength electrode in a multi-longitudinal-mode-coupled resonator type SAW filter. The resonator type SAW filter includes, on a piezoelectric substrate, an input interdigital transducer that excites a surface acoustic wave, an output interdigital transducer that receives the surface acoustic wave excited by the input interdigital transducer, a control interdigital transducer interposed between the input interdigital transducer and the output interdigital transducer that controls a state of the surface acoustic wave, and a pair of reflectors arranged on outer sides of both the input interdigital transducer and the output interdigital transducer. And, the input interdigital transducer, the output interdigital transducer, and the control interdigital transducer alternatively arrange two different zones C and E.

Abstract: A surface acoustic wave element includes a pair of interdigital transducers arranged in parallel with a propagation direction of a surface acoustic wave; a reflector prepared at both sides of the interdigital transducers; and a coupling portion, which mutually couples one end of a plurality of electrode fingers constituting one electrode portion of each interdigital transducer to be in common, wherein each of the electrode fingers includes a plurality of straight line portions that intersect with the coupling portion, and a bending portion prepared between these straight line portions.

Abstract: A surface acoustic wave (SAW) resonator, including: a first interdigital transducer composed of a pair of interdigital electrodes provided in a propagation direction of a surface acoustic wave; a second interdigital transducer composed of a pair of interdigital electrodes provided in parallel to the first interdigital transducer; and a switch that alternately switches the pair of interdigital electrodes of the first interdigital transducer and the pair of interdigital electrodes of the second interdigital transducer; wherein 7??B?33? where ? is a wavelength of a surface acoustic wave, and B is an addition of a width a1 of an engaged section of electrode fingers of the first interdigital transducer, a width a2 of an engaged section of electrode fingers of the second interdigital transducer, and a distance b between the engaged sections of both interdigital transducers.

Abstract: A SAW filter including a piezoelectric substrate 11, an input electrode 12 and an output electrode 13 each representing an interdigital electrode disposed on the piezoelectric substrate 11 and two reflectors 14 and 14 disposed on the piezoelectric substrate 11 in an arrangement sandwiching both the input electrode 12 and the output electrode 13 between the reflectors. Each of the electrodes 12 and 13 include a plurality of electrode fingers 121, 122 and 131, 132 respectively. The electrode fingers are partially bent at an angle and include at least two linear sections which are spaced at a distance of ?/2 from one another in the propagating direction of the SAWs. The electrode fingers 131 and 132 of the output electrode 13 and electrode fingers 141 of the reflector 14 are structured similarly to the electrode fingers 121 and 122 of the input electrode 12.

Abstract: A surface acoustic wave element includes a pair of interdigital transducers arranged in parallel with a propagation direction of a surface acoustic wave; a reflector prepared at both sides of the interdigital transducers; and a coupling portion, which mutually couples one end of a plurality of electrode fingers constituting one electrode portion of each interdigital transducer to be in common, wherein each of the electrode fingers includes a plurality of straight line portions that intersect with the coupling portion, and a bending portion prepared between these straight line portions.

Abstract: The invention provides a longitudinal double-mode SAW filter that has a large reflection coefficient by the electrode conductors and having flat pass band characteristics. In the longitudinal double-mode SAW filter, nearly all of higher-order natural mode oscillation displacements A0, S1 and A1 are made present in the first and second interdigital transducer regions. An electrode finger phase weighting is formed to correspond to a BPSK sign where a phase sign changes into 0 or ? at a polarity-changing point on an electrode charge distribution function Q(x) that generates on the electrode due to natural modes of oscillation. A single pair of natural modes, which exist stationary in the direction X of propagation of the surface acoustic waves that are utilized, is selected. A symmetrical mode charge distribution (Q(x), ?Q(x)) and an obliquely symmetrical mode charge distribution (Q(x), Q(x)) are generated in order to correspond to the regions of IDT1 and IDT2.

Abstract: A SAW filter including a piezoelectric substrate 11, an input electrode 12 and an output electrode 13 each representing an interdigital electrode disposed on the piezoelectric substrate 11 and two reflectors 14 and 14 disposed on the piezoelectric substrate 11 in an arrangement sandwiching both the input electrode 12 and the output electrode 13 between the reflectors. Each of the electrodes 12 and 13 include a plurality of electrode fingers 121, 122 and 131, 132 respectively. The electrode fingers are partially bent at an angle and include at least two linear sections which are spaced at a distance of ?/2 from one another in the propagating direction of the SAWs. The electrode fingers 131 and 132 of the output electrode 13 and electrode fingers 141 of the reflector 14 are structured similarly to the electrode fingers 121 and 122 of the input electrode 12.

Abstract: The invention provides a longitudinal double-mode SAW filter that has a large reflection coefficient by the electrode conductors and having flat pass band characteristics. In the longitudinal double-mode SAW filter, nearly all of higher-order natural mode oscillation displacements A0, S1 and A1 are made present in the first and second interdigital transducer regions. An electrode finger phase weighting is formed to correspond to a BPSK sign where a phase sign changes into 0 or &pgr; at a polarity-changing point on an electrode charge distribution function Q(x) that generates on the electrode due to natural modes of oscillation. A single pair of natural modes, which exist stationary in the direction X of propagation of the surface acoustic waves that are utilized, is selected. A symmetrical mode charge distribution (Q(x), −Q(x)) and an obliquely symmetrical mode charge distribution (Q(x), Q(x)) are generated in order to correspond to the regions of IDT1 and IDT2.