Abstract: A duplexer has an antenna terminal, a first terminal, and second terminals and provided with a first filter arranged between the antenna terminal and first terminal and including a parallel resonator for forming a ladder type filter circuit, a second filter arranged between the antenna terminal and the second terminal and having a passband higher than a passband of the first filter, and an electromagnetic coupling element arranged between the parallel resonator of the first filter and a ground part and electromagnetically coupled with the antenna terminal.

Abstract: The branching filter has the piezoelectric substrate having the main surface on which there are formed a transmission filter, which includes an input electrode and an antenna electrode, and a reception filter, which includes an output electrodes and the antenna electrode. The branching filter also has the mounting substrate having, on a first main surface, a first electrode group that is connected to the transmission filter and reception filter and that is formed symmetrical with respect to a line when viewed from the above, and also having, on a second main surface locating on the opposite side to the first main surface, a second electrode group that is connected to the circuit interconnects of an external circuit board and that is formed symmetrical with respect to a line when viewed from the above.

Abstract: [Problem] To provide a duplexer able to improve the isolation characteristic and the attenuation characteristic and a communication device using the same. [Solution] A configuration having an antenna terminal 4, a first terminal 1, and second terminals 2, 3 and provided with a first filter 5 arranged between the antenna terminal 4 and first terminal 1 and including a parallel resonator for forming a ladder type filter circuit, a second filter 6 arranged between the antenna terminal 4 and the second terminal 2 and having a passband higher than a passband of the first filter 5, and an electromagnetic coupling element 8 arranged between the parallel resonator of the first filter 5 and a ground part G and electromagnetically coupled with the antenna terminal 4.

Abstract: To provide a branching filter enabling sharing of the same mounting substrate between the normal arrangement and the mirror arrangement that is symmetric to the normal arrangement of an electrode group formed on a main surface of a piezoelectric substrate and a method for manufacturing the same. The branching filter 1 has the piezoelectric substrate 20 having the main surface on which there are formed a transmission filter 26, which includes an input electrode 22 and an antenna electrode 23, and a reception filter 27, which includes an output electrodes 24, 25 and the antenna electrode 23.

Abstract: An IDT electrode (3) on a piezoelectric substrate (2) has an electrode including first metal layers (31a, 31b) formed of titanium or a titanium alloy, or chromium or a chromium alloy and second metal layers (32a, 32b) formed of aluminum or an aluminum alloy, copper or a copper alloy, or gold or a gold alloy, which are laminated alternately. The orientation degrees in the first metal layer (31a) that is closest to the surface of the piezoelectric substrate (2) in the first metal layers (31a, 31b) and the second metal layer (32a) that is closest to the surface of the piezoelectric substrate (2) in the second metal layers (32a, 32b) are higher than the orientation degrees in the upper metal layers. As compared with the prior art where the orientation degrees in the first metal layers (31a, 31b) and the second metal layers (32a, 32b) are not considered, the power handling capability of the IDT electrode (3) can be significantly improved.

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: A second substrate 21 composed of a material having a lower dielectric constant than that of a piezoelectric substrate 2 having a transmission-side filter region 12 and a receiving-side filter region 13 formed therein is joined to the other main surface of the piezoelectric substrate 2, and a conductor layer 22 is formed throughout the other main surface of the second substrate 21. The effective dielectric constant of the substrate is reduced, thereby making it possible to reduce a parasitic capacitance formed between an input electrode section 5 in the transmission-side filter region 12 and an output electrode section 6 in the receiving-side filter region 13 and to improve isolation characteristics.

Abstract: A filter device includes a circuit board having a pattern electrode; a substrate having a filter to which a signal line for inputting or outputting a signal and a reference potential line having a reference potential are connected, and a pad electrode connected to the filter, the substrate being mounted on the circuit board such that the pad electrode and the pattern electrode face each other; and a connection part formed of the pad electrode, the pattern electrode, and a conductive member formed between the pattern electrode and the pad electrode to electrically connect the pattern electrode to the pad electrode, wherein the connection part is arranged to connect the signal line to the reference potential line.

Abstract: An IDT electrode (3) on a piezoelectric substrate (2) has an electrode including first metal layers (31a, 31b) formed of titanium or a titanium alloy, or chromium or a chromium alloy and second metal layers (32a, 32b) formed of aluminum or an aluminum alloy, copper or a copper alloy, or gold or a gold alloy, which are laminated alternately. The orientation degrees in the first metal layer (31a) that is closest to the surface of the piezoelectric substrate (2) in the first metal layers (31a, 31b) and the second metal layer (32a) that is closest to the surface of the piezoelectric substrate (2) in the second metal layers (32a, 32b) are higher than the orientation degrees in the upper metal layers. As compared with the prior art where the orientation degrees in the first metal layers (31a, 31b) and the second metal layers (32a, 32b) are not considered, the power handling capability of the IDT electrode (3) can be significantly improved.

Abstract: Terminal electrodes 9 for carrying a high frequency device 3 are formed on a surface of a circuit board having its reverse surface covered with a reverse surface conductor layer 6, and a plurality of signal lines 2 for exchanging a signal between the high frequency device 3 and an external circuit are formed thereon. The terminal electrode 9 is arranged at the center of the circuit board, and the signal lines 2 radially extends from the terminal electrode 9. Electromagnetic interference between the signal lines 2 can be reduced, so that out-of-band attenuation characteristics and isolation characteristics can be satisfactorily exhibited in a case where the high frequency device 3 is a duplexer.

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: After electrode patterning on an electrode forming surface of a piezoelectric substrate 2 (FIG. 1(b)), a conductor layer is formed on an electrode non-forming surface of the piezoelectric substrate 2 (FIG. 1(c)). After forming the conductor layer, the conductor layer formed on the other surface is removed (FIG. 1(f)) after at least one step (FIG. 1(e)), and thereafter, dicing for separation into elements and mounting on a mounting substrate are carried out. By removing all the conductor layer on the other surface of the piezoelectric substrate, the out-of-passband attenuation and isolation performance can be significantly improved.

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: In a surface acoustic wave element 10, in which IDT electrodes 31 and 32, a grounding electrode 37, etc. are formed one main surface of a piezoelectric substrate 20, resistors 40 made of a semiconductor are provided to connection electrodes 38 that interconnect the respective electrodes. By forcing the charges generated in the IDT electrodes to move via the resistors 40, it is possible to provide a compact, highly reliable surface acoustic wave apparatus capable of preventing an electrostatic discharge damage in the IDT electrodes.

Abstract: In a surface acoustic wave device according to the present invention, a transmitting filter element TX and a receiving filter element RX are formed on one main surface of a piezoelectric substrate 300, and are mounted by face down on an upper surface of a circuit board 200. A ground electrode 322 in the receiving filter element RX is connected to three linear via conductors 221? formed on the circuit board 200, and a ground electrode 312 in the transmitting filter element TX is connected to a crank-shaped via conductor 211? formed on the circuit board 200.

Abstract: Terminal electrodes 9 for carrying a high frequency device 3 are formed on a surface of a circuit board having its reverse surface covered with a reverse surface conductor layer 6, and a plurality of signal lines 2 for exchanging a signal between the high frequency device 3 and an external circuit are formed thereon. The terminal electrode 9 is arranged at the center of the circuit board, and the signal lines 2 radially extends from the terminal electrode 9. Electromagnetic interference between the signal lines 2 can be reduced, so that out-of-band attenuation characteristics and isolation characteristics can be satisfactorily exhibited in a case where the high frequency device 3 is a duplexer.

Abstract: A filter device includes a circuit board having a pattern electrode; a substrate having a filter to which a signal line for inputting or outputting a signal and a reference potential line having a reference potential are connected, and a pad electrode connected to the filter, the substrate being mounted on the circuit board such that the pad electrode and the pattern electrode face each other; and a connection part formed of the pad electrode, the pattern electrode, and a conductive member formed between the pattern electrode and the pad electrode to electrically connect the pattern electrode to the pad electrode, wherein the connection part is arranged to connect the signal line to the reference potential line.

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.