Patents by Inventor Yoshikuni Matsunaga
Yoshikuni Matsunaga 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).
-
Patent number: 7049892Abstract: A multistage high frequency power amplifier circuit device has a plurality of semiconductor amplification elements connected in a cascade. The circuit device is provided with a bias control circuit used to control the bias voltage or bias current of the output semiconductor amplification element in each stage so as to reduce the variation of the output power with respect to the power control signal voltage in an area around the threshold voltage of the semiconductor amplification elements. This realizes a high frequency power amplifier circuit device provided with excellent controllability of the output power and high efficiency at the time of low power output realized with use of such a control voltage as a power control signal.Type: GrantFiled: May 21, 2004Date of Patent: May 23, 2006Assignees: Renesas Technology Corp., Hitachi Communications Systems, Inc.Inventors: Yoshikuni Matsunaga, Toshihiko Shimizu, Tomio Furuya, Nobuhiro Matsudaira, Koichi Matsushita
-
Patent number: 6865399Abstract: In a mobile telephone apparatus corresponding to dual-band provided with an RF power module to operate in two kinds of different frequencies, a common harmonics control circuit is provided to the output circuit of such RF power module to realize higher efficiency in view of controlling respective harmonics power for both band frequencies. Moreover, a means for selectively setting the bias is also provided so that the maximum efficiency can be attained depending on the output power required with respective communication systems with the bias control signal output from the CPU of the control unit interlocking with selection of frequency of the mobile telephone apparatus body.Type: GrantFiled: February 5, 2002Date of Patent: March 8, 2005Assignee: Renesas Technology Corp.Inventors: Toru Fujioka, Isao Yoshida, Mineo Katsueda, Masatoshi Morikawa, Yoshikuni Matsunaga, Kenji Sekine, Osamu Kagaya
-
Publication number: 20050030107Abstract: Power amplifier circuits which constitute an RF power module used for a digital device capable of handling high frequency signals in two frequency bands are disposed over the same IC chip. The power amplifier circuits are disposed around the IC chip, and a secondary circuit is disposed between the power amplifier circuits. Thus, the power amplifier circuits are provided within the same IC chip to enable a size reduction. Further, the distance between the power amplifier circuits is ensured even if the power amplifier circuits are provided within the same IC chip. It is therefore possible to suppress the coupling between the power amplifier circuits and restrain crosstalk between the power amplifier circuits.Type: ApplicationFiled: July 14, 2004Publication date: February 10, 2005Inventors: Toshihiko Shimizu, Yoshikuni Matsunaga, Yuri Kusakari
-
Publication number: 20040212436Abstract: A multistage high frequency power amplifier-circuit device has a plurality of semiconductor amplification elements connected in a cascade. The circuit device is provided with a bias control circuit used to control the bias voltage or bias current of the output semiconductor amplification element in each stage so as to reduce the variation of the output power with respect to the power control signal voltage in an area around the threshold voltage of the semiconductor amplification elements. This realizes a high frequency power amplifier circuit device provided with excellent controllability of the output power and high efficiency at the time of low power output realized with use of such a control voltage as a power control signal.Type: ApplicationFiled: May 21, 2004Publication date: October 28, 2004Applicants: Renesas Technology Corp., Hitachi Communications Systems, Inc.Inventors: Yoshikuni Matsunaga, Toshihiko Shimizu, Tomio Furuya, Nobuhiro Matsudaira, Koichi Matsushita
-
Patent number: 6759906Abstract: A multistage high frequency power amplifier circuit device has a plurality of semiconductor amplification elements connected in a cascade. The circuit device is provided with a bias control circuit used to control the bias voltage or bias current of the output semiconductor amplification element in each stage so as to reduce the variation of the output power with respect to the power control signal voltage in an area around the threshold voltage of the semiconductor amplification elements. This realizes a high frequency power amplifier circuit device provided with excellent controllability of the output power and high efficiency at the time of low power output realized with use of such a control voltage as a power control signal.Type: GrantFiled: June 14, 2002Date of Patent: July 6, 2004Assignees: Renesas Technology Corp., Hitachi Communication Systems, Inc.Inventors: Yoshikuni Matsunaga, Toshihiko Shimizu, Tomio Furuya, Nobuhiro Matsudaira, Koichi Matsushita
-
Patent number: 6535069Abstract: A radio frequency power amplifier module for a dual-band type mobile communication apparatus that can transmit and receive a first frequency f1 and second frequency f2 (f2=2×f1). It includes a drive stage amplifier having the gain peaks at f1 and f2 with a matching circuit and a radio frequency power output circuit including a radio frequency power output transistor. The output circuit has a transmission line connected to the drain end of the output transistor, a parallel resonance circuit connected in series to the transmission line to resonate at harmonics of a frequency twice the frequency f2, a series resonance circuit provided between one end of the resonance circuit and the ground to resonate at harmonics of a frequency twice the frequency f2 and an output matching circuit provided in series to the other end of the parallel resonance circuit for matching with f1 and f2.Type: GrantFiled: February 28, 2002Date of Patent: March 18, 2003Assignee: Hitachi, Ltd.Inventors: Toru Fujioka, Isao Yoshida, Mineo Katsueda, Masatoshi Morikawa, Yoshikuni Matsunaga, Kenji Sekine, Osamu Kagaya
-
Publication number: 20030016082Abstract: A multistage high frequency power amplifier circuit device has a plurality of semiconductor amplification elements connected in a cascade. The circuit device is provided with a bias control circuit used to control the bias voltage or bias current of the output semiconductor amplification element in each stage so as to reduce the variation of the output power with respect to the power control signal voltage in an area around the threshold voltage of the semiconductor amplification elements. This realizes a high frequency power amplifier circuit device provided with excellent controllability of the output power and high efficiency at the time of low power output realized with use of such a control voltage as a power control signal.Type: ApplicationFiled: June 14, 2002Publication date: January 23, 2003Inventors: Yoshikuni Matsunaga, Toshihiko Shimizu, Tomio Furuya, Nobuhiro Matsudaira, Koichi Matsushita
-
Patent number: 6492872Abstract: A high frequency power amplifier module is provided for improving output controllability. A wireless communication apparatus incorporates a high frequency power amplifier module in a multi-stage configuration including a plurality of cascaded MOSFETS. The power amplifier module comprises a bias circuit for generating a gate voltage in response to a power control voltage (vapc) generated based on a power control signal of the wireless communication apparatus. The gate voltage has a bias pattern which presents smaller fluctuations in output power in response to a control voltage (Vapc) in a region near a threshold voltage (Vth) of the MOSFETs in respective amplification stages. In this way, the controllability for the output power is improved. More specifically, the power amplifier module has a gate bias circuit for generating the gate voltage (Vg) which follows a gate voltage pattern.Type: GrantFiled: September 7, 2000Date of Patent: December 10, 2002Assignees: Hitachi, Ltd., Hitachi Tohbu Semiconductor, Ltd.Inventors: Toru Fujioka, Yoshikuni Matsunaga, Isao Yoshida, Masatoshi Morikawa, Masao Hotta, Tetsuaki Adachi
-
Publication number: 20020089380Abstract: A radio frequency power amplifier module for a dual-band type mobile communication apparatus that can transmit and receive the first frequency f1 and the second frequency f2 (f2=2×f1) is structured as explained below.Type: ApplicationFiled: February 28, 2002Publication date: July 11, 2002Applicant: Hitachi, Ltd.Inventors: Toru Fujioka, Isao Yoshida, Mineo Katsueda, Masatoshi Morikawa, Yoshikuni Matsunaga, Kenji Sekine, Osamu Kagaya
-
Publication number: 20020082045Abstract: In a mobile telephone apparatus corresponding to dual-band provided with an RF power module to operate in two kinds of different frequencies, a common harmonics control circuit is provided to the output circuit of such RF power module to realize higher efficiency in view of controlling respective harmonics power for both band frequencies. Moreover, a means for selectively setting the bias is also provided so that the maximum efficiency can be attained depending on the output power required with respective communication systems with the bias control signal output from the CPU of the control unit interlocking with selection of frequency of the mobile telephone apparatus body. In addition, a switching element is also provided to such harmonics control circuit to enable the harmonics control without giving any influence on the radio frequency signal of each communication system.Type: ApplicationFiled: February 5, 2002Publication date: June 27, 2002Inventors: Toru Fujioka, Isao Yoshida, Mineo Katsueda, Masatoshi Morikawa, Yoshikuni Matsunaga, Kenji Sekine, Osamu Kagaya
-
Patent number: 6384688Abstract: A radio frequency power amplifier module for a dual-band type mobile communication apparatus that can transmit and receive the first frequency f1 and the second frequency f2 (f2=2×f1) is structured as explained below. This radio frequency power amplifier module for dual-band type mobile communication apparatus is comprised of a drive stage amplifier having the gain peaks at f1 and f2 with a matching circuit and a radio frequency power output circuit including a radio frequency power output transistor.Type: GrantFiled: October 25, 2000Date of Patent: May 7, 2002Assignee: Hitachi, Ltd.Inventors: Toru Fujioka, Isao Yoshida, Mineo Katsueda, Masatoshi Morikawa, Yoshikuni Matsunaga, Kenji Sekine, Osamu Kagaya
-
Patent number: 6366788Abstract: In a mobile telephone apparatus corresponding to dual-band provided with an RF power module to operate in two kinds of different frequencies, a common harmonics control circuit is provided to the output circuit of such RF power module to realize higher efficiency in view of controlling respective harmonics power for both band frequencies. Moreover, a means for selectively setting the bias is also provided so that the maximum efficiency can be attained depending on the output power required with respective communication systems with the bias control signal output from the CPU of the control unit interlocking with selection of frequency of the mobile telephone apparatus body.Type: GrantFiled: October 26, 2000Date of Patent: April 2, 2002Assignee: Hitachi, Ltd.Inventors: Toru Fujioka, Isao Yoshida, Mineo Katsueda, Masatoshi Morikawa, Yoshikuni Matsunaga, Kenji Sekine, Osamu Kagaya
-
Patent number: 5951474Abstract: RF receiving coil device used in a magnetic resonance imaging apparatus capable of acquiring a tomographic image of an object under examination positioned in a static magnetic field along a predetermined direction including quadrature detection coils for detecting an MR signal component along a direction perpendicular to a body axis direction of the object under examination and also perpendicular to a direction of the static magnetic field, and for detecting another MR-signal component along the body axis direction.Type: GrantFiled: February 24, 1997Date of Patent: September 14, 1999Assignee: Hitachi Medical CorporationInventors: Yoshikuni Matsunaga, Tetsuhiko Takahashi
-
Patent number: 5592088Abstract: A probe for an MRI apparatus in a vertical magnetic field system including: an array coil which is formed by arranging a plurality of unit coils, which can be driven independently of one another, in a direction perpendicularly intersecting a direction of a static magnetic field; and a compensating coil which forms a magnetic field in a direction perpendicularly intersecting both a direction of a magnetic field formed by the array coil and the direction of the magnetic field, a signal detected by the array coil and a signal detected by the compensating coil being composed so as to be in phase with each other, thereby to be outputted.Type: GrantFiled: April 26, 1995Date of Patent: January 7, 1997Assignees: Hitachi, Ltd., Hitachi Medical CorporationInventors: Yoshikuni Matsunaga, Tetsuhiko Takahashi, Etsuji Yamamoto
-
Patent number: 5559434Abstract: An MRI RF coil including first and second ring elements having a plurality of peripheral segments connected in ring shape which are apart from each other along a common vertical axial line. The RF coil also includes a plurality of axial conductive segments for connecting the first and second ring elements electrically to each other at the contacts of the plurality of peripheral segments with a plurality of current loops being formed by neighboring axial conductive segments and two peripheral segments connected thereby. Further, at least one control signal feeding point is positioned at any one of the peripheral segments of the first or second ring elements.Type: GrantFiled: August 18, 1995Date of Patent: September 24, 1996Assignee: Hitachi, Ltd.Inventors: Tetsuhiko Takahashi, Etsuji Yamamoto, Yoshiki Murakami, Yoshikuni Matsunaga
-
Patent number: 5552707Abstract: An RF probe including: two coils for detecting MR signals which are arranged at positions which face each other at a predetermined distance; an apparatus for changing a distance between those coils; and an apparatus for reducing a high frequency coupling between the two coils which is caused due to a change in distance between the coils, in accordance with the distance between the coils.Type: GrantFiled: August 29, 1994Date of Patent: September 3, 1996Assignee: Hitachi Medical CorporationInventors: Tetsuhiko Takahashi, Hiroyuki Takeuchi, Yoshikuni Matsunaga
-
Patent number: 5510714Abstract: In a bird cage resonator, the axial length of rungs is changed between orthogonal elements. By doing this, the real view fields of orthogonal ports A and B in the sagittal direction are changed and the sensitivity difference between both view fields is reduced. For an object with an elliptical section to be inspected such as the human body, a remarkable difference in detection sensitivity between each orthogonal ports is eliminated and the receiving sensitivity of MRI apparatus employing the QD method is improved.Type: GrantFiled: August 10, 1992Date of Patent: April 23, 1996Assignee: Hitachi, Ltd.Inventors: Tetsuhiko Takahashi, Etsuji Yamamoto, Yoshiki Murakami, Yoshikuni Matsunaga
-
Patent number: 5489847Abstract: An RF probe for MRI, in which a plurality of unit coils including conductive loops having resonance capacitors and inductors connected with the conductive loops in series are arranged so as to be distant from each other with a predetermined distance, electromagnetic coupling being produced between at least two inductors to remove electromagnetic coupling between the unit coils.Type: GrantFiled: June 1, 1994Date of Patent: February 6, 1996Assignees: Hitachi, Ltd., Hitachi Medical Corp.Inventors: Takayuki Nabeshima, Tetsuhiko Takahashi, Yoshikuni Matsunaga, Etsuji Yamamoto, Kageyoshi Katakura
-
Patent number: 5477145Abstract: In an RF probe comprising a resonator and a pickup coil, the pickup coil is an 8-shaped coil, and a center portion of this pickup coil is constituted in such a manner that crossing coils become parallel to each other at the portion. The center portion where the coils of the pickup coil are parallel to each other is so disposed as to extend along, and in the vicinity of, a part of a conductor loop of the resonator.Type: GrantFiled: January 5, 1994Date of Patent: December 19, 1995Assignee: Hitachi Medical CorporationInventors: Tetsuhiko Takahashi, Yoshikuni Matsunaga, Etsuji Yamamoto
-
Patent number: 5457386Abstract: A probe for an MRI apparatus in a vertical magnetic field system including: an array coil which is formed by arranging a plurality of unit coils, which can be driven independently of one another, in a direction perpendicularly intersecting a direction of a static magnetic field; and a compensating coil which forms a magnetic field in a direction perpendicularly intersecting both a direction of a magnetic field formed by the array coil and the direction of the magnetic field, a signal detected by the array coil and a signal detected by the compensating coil being composed so as to be in phase with each other, thereby to be outputted.Type: GrantFiled: November 25, 1992Date of Patent: October 10, 1995Assignees: Hitachi, Ltd., Hitachi Medical CorporationInventors: Yoshikuni Matsunaga, Tetsuhiko Takahashi, Etsuji Yamamoto