Patents by Inventor Kunihiro Kawai
Kunihiro Kawai has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 9356644Abstract: A wireless circuit that can be used in a plurality of frequency bands even if its duplexer is formed of current variable frequency filters is provided. The circuit includes a transmission-reception antenna 911, a variable frequency duplexer 131, a double-pole six-throw switch 923, an RFIC 180, and a controller 190 which executes switching operations in accordance with control signals. The RFIC 180 determines a pair of frequency bands for transmission and reception signals input to the variable frequency duplexer 131 and generates and sends the control signals to perform switching control operations to connect a transmission port corresponding to the determined transmission frequency band with the transmission terminal of the variable frequency duplexer 131 and to connect a reception port corresponding to the determined reception frequency band with the reception terminal of the variable frequency duplexer 131 and to perform a frequency switching operation of the variable frequency duplexer 131.Type: GrantFiled: July 10, 2013Date of Patent: May 31, 2016Assignee: NTT DOCOMO, INC.Inventors: Hiroshi Okazaki, Kunihiro Kawai, Shoichi Narahashi, Yuta Takagi, Takayuki Furuta
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Patent number: 9337990Abstract: A front-end circuit includes an RFIC, an antenna, N duplexers, N variable impedance adjustment circuits, a switch for selecting any two of the N variable impedance adjustment circuits, and a control unit which receives a control signal from the RFIC, where 2?N. The control unit executes switching operations of the N variable impedance adjustment circuits and the switch in accordance with control information. The control signal indicates to 1) control the switch to select two variable impedance adjustment circuits corresponding to a p-th frequency band and a q-th frequency band respectively, 2) control a variable impedance adjustment circuit corresponding to the p-th frequency band to increase input impedance in the q-th frequency band as viewed from the antenna side and 3) control a variable impedance adjustment circuit corresponding to the q-th frequency band to increase input impedance in the p-th frequency band as viewed from the side.Type: GrantFiled: July 9, 2013Date of Patent: May 10, 2016Assignee: NTT DOCOMO, INC.Inventors: Shoichi Narahashi, Hiroshi Okazaki, Kunihiro Kawai, Yuta Takagi, Takayuki Furuta
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Publication number: 20140349592Abstract: A wireless circuit that can be used in a plurality of frequency bands even if its duplexer is formed of current variable frequency filters is provided. The circuit includes a transmission-reception antenna 911, a variable frequency duplexer 131, a double-pole six-throw switch 923, an RFIC 180, and a controller 190 which executes switching operations in accordance with control signals. The RFIC 180 determines a pair of frequency bands for transmission and reception signals input to the variable frequency duplexer 131 and generates and sends the control signals to perform switching control operations to connect a transmission port corresponding to the determined transmission frequency band with the transmission terminal of the variable frequency duplexer 131 and to connect a reception port corresponding to the determined reception frequency band with the reception terminal of the variable frequency duplexer 131 and to perform a frequency switching operation of the variable frequency duplexer 131.Type: ApplicationFiled: July 10, 2013Publication date: November 27, 2014Applicant: NTT DOCOMO, INC.Inventors: Hiroshi Okazaki, Kunihiro Kawai, Shoichi Narahashi, Yuta Takagi, Takayuki Furuta
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Publication number: 20140321312Abstract: Provided is a front-end circuit which can prevent a signal from leaking into another circuit even when signals are sent and received simultaneously in multiple frequency bands in carrier aggregation.Type: ApplicationFiled: July 9, 2013Publication date: October 30, 2014Applicant: NTT DOCOMO, INC.Inventors: Shoichi Narahashi, Hiroshi Okazaki, Kunihiro Kawai, Yuta Takagi, Takayuki Furuta
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Patent number: 8773223Abstract: A switch is replaced with a parallel resonant circuit 4. More specifically, a variable resonator includes a line part 1 that includes one or more lines and has an annular shape, at least two parallel resonant circuits 4 capable of changing a characteristic, and at least three variable reactance blocks 2 capable of changing a reactance value, in which the parallel resonant circuits 4 are electrically connected to the line part 1 at one end thereof at different positions on the line part 1, and the variable reactance blocks 2 are electrically connected to the line part 1 at predetermined intervals based on an electrical length at a resonance frequency.Type: GrantFiled: November 12, 2010Date of Patent: July 8, 2014Assignee: NTT DoCoMo, Inc.Inventors: Kunihiro Kawai, Hiroshi Okazaki, Shoichi Narahashi
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Patent number: 8760244Abstract: A variable resonator includes a first transmission line 101, a second transmission line 102 and a plurality of switch circuits 150. The electrical length of the first transmission line 101 is equal to the electrical length of the second transmission line 102. The characteristic impedance for the even mode of the first transmission line 101 is equal to the characteristic impedance for the even mode of the second transmission line 102. The characteristic impedance for the odd mode of the first transmission line 101 is equal to the characteristic impedance for the odd mode of the second transmission line 102. Each switch circuit 150 is connected to any of the first transmission line 101 and the second transmission line 102, and one of the switch circuits 150 is turned on.Type: GrantFiled: March 4, 2011Date of Patent: June 24, 2014Assignee: NTT DoCoMo, Inc.Inventors: Kunihiro Kawai, Hiroshi Okazaki, Shoichi Narahashi
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Patent number: 8648666Abstract: A multimode frontend circuit of the present invention comprises two transmission paths. Each of the transmission paths comprises two input/output lines, a first transmission line having one end connected to one of the input/output lines and the other end connected to the other input/output line, a second transmission line connected to the one of the input/output lines and the other end connected to the other input/output line, and one or more termination switch circuits. The termination switch circuit or circuits comprise a switch having one end connected to one of the first and second transmission lines and a termination circuit connected to the other end of the switch. Each of the transmission lines may comprise one or more short-circuiting switches. The short-circuiting switch or switches are capable of short-circuiting between the two transmission lines at positions at the same electrical length from one of the input/output lines.Type: GrantFiled: August 24, 2011Date of Patent: February 11, 2014Assignee: NTT DoCoMo, Inc.Inventors: Kunihiro Kawai, Hiroshi Okazaki, Shoichi Narahashi
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Patent number: 8581677Abstract: A variable resonator includes a ring-shaped conductor line (2) which is provided on a dielectric substrate (5) and has a circumferential length of a wavelength at a resonance frequency or an integral multiple of the wavelength, and at least two circuit switches (31, 32), wherein the circuit switches (31, 32) have one ends (31) electrically connected to the ring-shaped conductor line (2) and the other ends (32) electrically connected to a ground conductor (4) formed on the dielectric substrate (5), electrical connection/disconnection between the ground conductor (4) and ring-shaped conductor line (2) can be switched, and the one ends (31) of the circuit switches (31, 32) are connected to the ring-shaped conductor line (2) on different portions.Type: GrantFiled: September 13, 2012Date of Patent: November 12, 2013Assignee: NTT DoCoMo, Inc.Inventors: Kunihiro Kawai, Hiroshi Okazaki, Shoichi Narahashi
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Patent number: 8564384Abstract: A variable resonator that comprises a loop line (902) to which two or more switches (903) are connected and N of reactance circuits (102) (N?3), in which switches (903) are severally connected to different positions on the loop line (902), the other ends of the switches are severally connected to a ground conductor, and the switches are capable of switching electrical connection/non-connection between the ground conductor and the loop line (902), the reactance circuits (102) severally have the same reactance value, the loop line (902) has a circumference corresponding to one wavelength or integral multiple thereof at a resonance frequency corresponding to each reactance value of each reactance circuit, and the reactance circuits (102) are electrically connected to the loop line (902) as branching circuits along the circumference direction of the loop line (902) at equal electrical length intervals.Type: GrantFiled: October 31, 2012Date of Patent: October 22, 2013Assignee: NTT DoCoMo, Inc.Inventors: Kunihiro Kawai, Hiroshi Okazaki, Shoichi Narahashi
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Publication number: 20130002374Abstract: A variable resonator includes a ring-shaped conductor line (2) which is provided on a dielectric substrate (5) and has a circumferential length of a wavelength at a resonance frequency or an integral multiple of the wavelength, and at least two circuit switches (31, 32), wherein the circuit switches (31, 32) have one ends (31) electrically connected to the ring-shaped conductor line (2) and the other ends (32) electrically connected to a ground conductor (4) formed on the dielectric substrate (5), electrical connection/disconnection between the ground conductor (4) and ring-shaped conductor line (2) can be switched, and the one ends (31) of the circuit switches (31, 32) are connected to the ring-shaped conductor line (2) on different portions.Type: ApplicationFiled: September 13, 2012Publication date: January 3, 2013Applicant: NTT DoCoMo, Inc.Inventors: Kunihiro KAWAI, Hiroshi Okazaki, Shoichi Narahashi
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Patent number: 8330562Abstract: A variable resonator that comprises a loop line (902) to which two or more switches (903) are connected and N variable reactance means (102) (N?3), in which switches (903) are severally connected to different positions on the loop line (902), the other ends of the switches are severally connected to a ground conductor, and the switches are capable of switching electrical connection/non-connection between the ground conductor and the loop line (902), the variable reactance blocks (102) are severally settable to the same reactance value, and the variable reactance blocks (102) are electrically connected to the loop line (902) as branching circuits along the circumference direction of the loop line (902) at equal electrical length intervals.Type: GrantFiled: January 4, 2012Date of Patent: December 11, 2012Assignee: NTT DoCoMo, Inc.Inventors: Kunihiro Kawai, Hiroshi Okazaki, Shoichi Narahashi
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Patent number: 8324988Abstract: A variable resonator that comprises a loop line (902) to which two or more switches (903) are connected and N of reactance circuits (102) (N?3), in which switches (903) are severally connected to different positions on the loop line (902), the other ends of the switches are severally connected to a ground conductor, and the switches are capable of switching electrical connection/non-connection between the ground conductor and the loop line (902), the reactance circuits (102) severally have the same reactance value, the loop line (902) has a circumference corresponding to one wavelength or integral multiple thereof at a resonance frequency corresponding to each reactance value of each reactance circuit, and the reactance circuits (102) are electrically connected to the loop line (902) as branching circuits along the circumference direction of the loop line (902) at equal electrical length intervals.Type: GrantFiled: February 21, 2008Date of Patent: December 4, 2012Assignee: NTT DoCoMo, Inc.Inventors: Kunihiro Kawai, Hiroshi Okazaki, Shoichi Narahashi
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Patent number: 8294537Abstract: A variable resonator includes a ring-shaped conductor line (2) which is provided on a dielectric substrate (5) and has a circumferential length of a wavelength at a resonance frequency or an integral multiple of the wavelength, and at least two circuit switches (31, 32), wherein the circuit switches (31, 32) have one ends (31) electrically connected to the ring-shaped conductor line (2) and the other ends (32) electrically connected to a ground conductor (4) formed on the dielectric substrate (5), electrical connection/disconnection between the ground conductor (4) and ring-shaped conductor line (2) can be switched, and the one ends (31) of the circuit switches (31, 32) are connected to the ring-shaped conductor line (2) on different portions.Type: GrantFiled: September 7, 2007Date of Patent: October 23, 2012Assignee: NTT DoCoMo, Inc.Inventors: Kunihiro Kawai, Hiroshi Okazaki, Shoichi Narahashi
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Publication number: 20120098616Abstract: A variable resonator that comprises a loop line (902) to which two or more switches (903) are connected and N variable reactance means (102) (N?3), in which switches (903) are severally connected to different positions on the loop line (902), the other ends of the switches are severally connected to a ground conductor, and the switches are capable of switching electrical connection/non-connection between the ground conductor and the loop line (902), the variable reactance blocks (102) are severally settable to the same reactance value, and the variable reactance blocks (102) are electrically connected to the loop line (902) as branching circuits along the circumference direction of the loop line (902) at equal electrical length intervals.Type: ApplicationFiled: January 4, 2012Publication date: April 26, 2012Applicant: NTT DoCoMo, IncInventors: Kunihiro KAWAI, Hiroshi Okazaki, Shoichi Narahashi
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Patent number: 8138852Abstract: A duplexer according to the present invention includes a first port, a second port and a third port for external input/output, a first path formed between the first port and the third port, a second path formed between the second port and the third port, a phase shifting part provided for each path, and a resonating part provided for each path. At least any of the resonating parts has a ring conductor having a length equal to one wavelength at a resonant frequency or an integral multiple thereof, a plurality of passive circuits, and a plurality of switches each of which is connected to a different part of the ring conductor at one end and to any of the passive circuits at the other end. A switch may simply be connected to a ground conductor instead of being connected to the passive circuit.Type: GrantFiled: October 28, 2008Date of Patent: March 20, 2012Assignee: NTT DoCoMo, Inc.Inventors: Kunihiro Kawai, Hiroshi Okazaki, Shoichi Narahashi
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Publication number: 20120049985Abstract: A multimode frontend circuit of the present invention comprises two transmission paths. Each of the transmission paths comprises two input/output lines, a first transmission line having one end connected to one of the input/output lines and the other end connected to the other input/output line, a second transmission line connected to the one of the input/output lines and the other end connected to the other input/output line, and one or more termination switch circuits. The termination switch circuit or circuits comprise a switch having one end connected to one of the first and second transmission lines and a termination circuit connected to the other end of the switch. Each of the transmission lines may comprise one or more short-circuiting switches. The short-circuiting switch or switches are capable of short-circuiting between the two transmission lines at positions at the same electrical length from one of the input/output lines.Type: ApplicationFiled: August 24, 2011Publication date: March 1, 2012Applicant: NTT DOCOMO, INC.Inventors: Kunihiro Kawai, Hiroshi Okazaki, Shoichi Narahashi
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Patent number: 8125302Abstract: A signal selecting device according to the present invention has two input/output ports, a plurality of resonating parts, a plurality of impedance transforming parts, and a controlling part. The resonating parts have a ring conductor having a length equal to one wavelength at a resonant frequency or an integral multiple thereof and a plurality of switches each of which is connected to a different part of the ring conductor at one end and to a ground conductor at the other end. The controlling part controls the state of the switches. The resonating parts are disposed in series between the two input/output ports. The impedance transforming parts are disposed between the input/output ports in such a manner that the impedance transforming parts at the both ends are disposed between the input/output port and the resonating part and the remaining impedance transforming parts are disposed between the resonating parts.Type: GrantFiled: September 9, 2008Date of Patent: February 28, 2012Assignee: NTT DoCoMo, Inc.Inventors: Kunihiro Kawai, Kei Satoh, Hiroshi Okazaki, Shoichi Narahashi
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Patent number: 8106727Abstract: A variable resonator that comprises a loop line (902) to which two or more switches (903) are connected and N variable reactance means (102) (N?3), in which switches (903) are severally connected to different positions on the loop line (902), the other ends of the switches are severally connected to a ground conductor, and the switches are capable of switching electrical connection/non-connection between the ground conductor and the loop line (902), the variable reactance blocks (102) are severally settable to the same reactance value, and the variable reactance blocks (102) are electrically connected to the loop line (902) as branching circuits along the circumference direction of the loop line (902) at equal electrical length intervals.Type: GrantFiled: February 21, 2008Date of Patent: January 31, 2012Assignee: NTT DoCoMo, Inc.Inventors: Kunihiro Kawai, Hiroshi Okazaki, Shoichi Narahashi
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Publication number: 20110215886Abstract: A variable resonator includes a first transmission line 101, a second transmission line 102 and a plurality of switch circuits 150. The electrical length of the first transmission line 101 is equal to the electrical length of the second transmission line 102. The characteristic impedance for the even mode of the first transmission line 101 is equal to the characteristic impedance for the even mode of the second transmission line 102. The characteristic impedance for the odd mode of the first transmission line 101 is equal to the characteristic impedance for the odd mode of the second transmission line 102. Each switch circuit 150 is connected to any of the first transmission line 101 and the second transmission line 102, and one of the switch circuits 150 is turned on.Type: ApplicationFiled: March 4, 2011Publication date: September 8, 2011Applicant: NTT DOCOMO, INC.Inventors: Kunihiro KAWAI, Hiroshi OKAZAKI, Shoichi NARAHASHI
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Publication number: 20110115574Abstract: A switch is replaced with a parallel resonant circuit 4. More specifically, a variable resonator includes a line part 1 that includes one or more lines and has an annular shape, at least two parallel resonant circuits 4 capable of changing a characteristic, and at least three variable reactance blocks 2 capable of changing a reactance value, in which the parallel resonant circuits 4 are electrically connected to the line part 1 at one end thereof at different positions on the line part 1, and the variable reactance blocks 2 are electrically connected to the line part 1 at predetermined intervals based on an electrical length at a resonance frequency.Type: ApplicationFiled: November 12, 2010Publication date: May 19, 2011Applicant: NTT DOCOMO, INC.Inventors: Kunihiro KAWAI, Hiroshi Okazaki, Shoichi Narahashi