Abstract: A surface acoustic wave device includes a first surface acoustic wave filter forming a ladder filter circuit; and a second surface acoustic wave filter having a passband at a frequency range higher than that of the first surface acoustic wave filter. The first surface acoustic wave filter includes a series-arm surface acoustic wave resonator, a parallel-arm surface acoustic wave resonator and an additional surface acoustic wave resonator. The series-arm surface acoustic wave resonator is on a series arm of the ladder filter circuit and includes an IDT electrode. The parallel-arm surface acoustic wave resonator is on a parallel arm of the ladder filter circuit and includes an IDT electrode. The additional surface acoustic wave resonator includes an IDT electrode, is connected in parallel with the series-arm surface acoustic wave resonator, and has a resonance frequency higher than the frequency range of the passband of the second surface acoustic wave filter.

Abstract: Disclosed is a surface acoustic wave resonator which comprises, on a piezoelectric substrate 19, an IDT electrode 1 including bus bar electrodes 12a, reflector electrodes 2 disposed to be adjacent to both sides of the IDT electrode 1 in a main propagation direction F of surface acoustic waves at the IDT electrode 1, and auxiliary reflector electrodes 3 that are disposed at four positions external to the reflector electrodes 2 on virtual straight lines extending from the bus bar electrodes 12a of the IDT electrode 1 in an inclined manner so that the periodic direction G of periodically arranged electrodes 14b is oriented toward the IDT electrode 1.

Abstract: A surface acoustic wave device includes a first surface acoustic wave filter forming a ladder filter circuit; and a second surface acoustic wave filter having a passband at a frequency range higher than that of the first surface acoustic wave filter. The first surface acoustic wave filter includes a series-arm surface acoustic wave resonator, a parallel-arm surface acoustic wave resonator and an additional surface acoustic wave resonator. The series-arm surface acoustic wave resonator is on a series arm of the ladder filter circuit and includes an IDT electrode. The parallel-arm surface acoustic wave resonator is on a parallel arm of the ladder filter circuit and includes an IDT electrode. The additional surface acoustic wave resonator includes an IDT electrode, is connected in parallel with the series-arm surface acoustic wave resonator, and has a resonance frequency higher than the frequency range of the passband of the second surface acoustic wave filter.

Abstract: An IDT electrode 2 and an electrode pad 3 are formed on one principal face of a piezoelectric substrate 1 and a circular electrode 4 is formed so as to surround these components. The circular electrode 4 is connected to a radiating conductor 15 formed on a bottom face of a circuit board 11 through a via conductor 14 formed within the circuit board 11. Thus, since heat generated in the IDT electrode 2 is easy to be released to the outside through the circular electrode 4, the via conductor 14 and the radiating conductor 15, adverse effects due to the heat can be prevented, thereby improving high power durability.

Abstract: An IDT electrode 3, and an input electrode section 5 and an output electrode section 6 each connecting with the IDT electrode 3 are formed in a filter region on one main surface of a piezoelectric substrate 2, and a semiconductor layer 22 is formed on the other main surface opposite to the one main surface of the piezoelectric substrate 2. The semiconductor layer 22 makes it possible to prevent pyroelectric destruction in the device manufacturing process as well as to prevent out-of-band attenuation characteristics from being degraded.

Abstract: A conductor layer 10 is provided so as to prevent pyroelectric destruction occurring in the steps of manufacturing a surface acoustic wave element 1 on the other surface opposite to an IDT electrode formation surface of a piezoelectric substrate 2. At this time, the conductor layer 10 is formed, except for a region 5a opposed to an input electrode section 5 in a filter region 9 and/or a region 6a opposed to an output electrode section 6. This allows a coupling amount between the input electrode section 5 and the output electrode section 6 due to a parasitic capacitance formed between the input electrode section 5 and the output electrode section 6 in the filter region 9 to be reduced, thereby allowing the out-of-band attenuation characteristics of a surface acoustic wave device to be improved.

Abstract: Disclosed is a surface acoustic wave resonator which comprises, on a piezoelectric substrate 19, an IDT electrode 1 including bus bar electrodes 12a, reflector electrodes 2 disposed to be adjacent to both sides of the IDT electrode 1 in a main propagation direction F of surface acoustic waves at the IDT electrode 1, and auxiliary reflector electrodes 3 that are disposed at four positions external to the reflector electrodes 2 on virtual straight lines extending from the bus bar electrodes 12a of the IDT electrode 1 in an inclined manner so that the periodic direction G of periodically arranged electrodes 14b is oriented toward the IDT electrode 1.

Abstract: An IDT electrode 3, and an input electrode section 5 and an output electrode section 6 each connecting with the IDT electrode 3 are formed in a filter region on one main surface of a piezoelectric substrate 2, and a semiconductor layer 22 is formed on the other main surface opposite to the one main surface of the piezoelectric substrate 2. The semiconductor layer 22 makes it possible to prevent pyroelectric destruction in the device manufacturing process as well as to prevent out-of-band attenuation characteristics from being degraded.

Abstract: An IDT electrode 2 and an electrode pad 3 are formed on one principal face of a piezoelectric substrate 1 and a circular electrode 4 is formed so as to surround these components. The circular electrode 4 is connected to a radiating conductor 15 formed on a bottom face of a circuit board 11 through a via conductor 14 formed within the circuit board 11. Thus, since heat generated in the IDT electrode 2 is easy to be released to the outside through the circular electrode 4, the via conductor 14 and the radiating conductor 15, adverse effects due to the heat can be prevented, thereby improving high power durability.

Abstract: A conductor layer 10 is provided so as to prevent pyroelectric destruction occurring in the steps of manufacturing a surface acoustic wave element 1 on the other surface opposite to an IDT electrode formation surface of a piezoelectric substrate 2. At this time, the conductor layer 10 is formed, except for a region 5a opposed to an input electrode section 5 in a filter region 9 and/or a region 6a opposed to an output electrode section 6. This allows a coupling amount between the input electrode section 5 and the output electrode section 6 due to a parasitic capacitance formed between the input electrode section 5 and the output electrode section 6 in the filter region 9 to be reduced, thereby allowing the out-of-band attenuation characteristics of a surface acoustic wave device to be improved.