Mitsubishi Denki Kabushiki Kaisha

Mitsubishi Electric Corporation

Nippon Steel Chemical & Material Co., Ltd.

Biglobe Inc.

Kazuhiko Nakahara

Teruyuki Shimura

Tadashi Takagi

Takahide Ishikawa

Kazutomi Mori

Naoto Andoh

Makoto Kimura

Koji Yamanaka

Miyo Miyashita

Yoshinobu Sasaki

Shintaro Shinjo

Takayuki Katoh

Nobuyuki Enomoto

Yoshitaka Kamo

Akira Inoue

Shinji Aono

Kousei Maemura

Yasuharu Nakajima

Eigo Kuwata

Kazuhisa Yamauchi

Takuo Kashiwa

Yasushi Itoh

Kazuo Ishihara

Ryota Komaru

Takanori Hiroshima

Dai Ninomiya

Tetsunari Saito

Masafumi Kawaseki

Tsugutoshi Wasano

There are provided a naphthol resin and an epoxy resin that impart characteristics such as high heat resistance, a low dielectric loss tangent, and a low coefficient of thermal expansion (CTE), and an epoxy resin composition including the naphthol resin or the epoxy resin as an essential component, and cured products thereof. A naphthol resin which is represented by the following formula: where Rrepresents a hydrogen atom or an alkyl group having 1 to 6 carbon atoms, and n represents the number of repetitions and is a number of 2 to 10, and in which, in terms of area ratio in GPC measurement, a ratio of components for which n=6 or more is 15% or more, and a ratio of components for which n=1 in GPC is 30% or less, and a hydroxy group equivalent is 260 to 400 g/eq.

Naphthol resin, epoxy resin, epoxy resin composition, and cured products thereof

A MIM capacitor is included in any one or more of a first matching circuit and a second matching circuit. The mat capacitor performs impedance matching of a fundamental wave included in a high-frequency signal with a transmission line, and forms a short-circuit point for a harmonic included in the high-frequency signal at a connection point with the transmission line.

High-frequency amplifier

A high-frequency switch includes: a first transistor connected to an input terminal and a first output terminal; a second transistor connected to the first output terminal; a third transistor connected to the second transistor and grounded; a resistor connected to a connection between the second and third transistors and grounded; a switching circuit switchable between a state in which the switching circuit allows passage of a transmitted/received signal between the input terminal and a second output terminal and a state in which the switching circuit cuts off the transmitted/received signal; and a control unit to control the first, second, and third transistors and the switching circuit. At the time of reception, the control unit brings the switching circuit into the state in which the switching circuit cuts off the transmitted/received signal, places the first and third transistors in an on-state, and places the second transistor in an off-state. At the time of transmission and reception with an automatic gain control operation, the control unit brings the switching circuit into the state in which the switching circuit allows the passage of the transmitted/received signal, brings the first and third transistors in an off-state, and brings the second transistor in an on-state.

High-frequency switch

To provide a terminal management apparatus capable of improving convenience in a state that power consumption is suppressed. A communication sectionreceives reporting information notifying the presence of a notification utilizing a first communication function directed to a terminal. When the communication sectionhas received the reporting information, a control sectiontransmits a message indicating the presence of the notification, to the terminalby using a second communication function different from the first communication function.

Terminal management apparatus, terminal, communication system, terminal management method, and program

A high-frequency semiconductor device according to the present invention achieves improvements in degradation of noise characteristics and a reduction in gain, and an improvement in reduction in power efficiency while suppressing a concentration of a current to multifinger HBTs. In the multifinger HBTs constituting a first stage and an output stage of an amplifier, basic HBTsthat constitute the multifinger HBTcorresponding to the first stage, are each made up of an HBTand an emitter resistorconnected to the corresponding emitter of the HBT, whereas basic HBTsthat constitute the multifinger HBTcorresponding to the output stage, are each comprised of an HBTand a base resistorconnected to the corresponding base of the HBT. The high-frequency semiconductor device according to the present invention is useful as a high output power amplifier used in satellite communications, ground microwave communications, mobile communications, etc.

High-frequency semiconductor device

A T-type circuit having series resistors and a parallel resistor is arranged on the outside of an amplifier, a signal is amplified in the amplifier while stabilizing the signal by using the T-type circuit functioning as a stabilizing circuit, and the amplified signal is output. In this case, values of the series resistors and the parallel resistor of the T-type circuit are determined so as to set an output load impedance obtained by seeing the output side of the high-frequency amplifier from the amplifier to a value near to or slightly lower than a value of the conjugate complex impedance of an output impedance of the amplifier. Therefore, the output signal having a high output electric power and a low distortion can be obtained in the high-frequency amplifier while keeping a gain and a noise characteristic of the high-frequency amplifier.

High-frequency amplifier and high-frequency multistage amplifier

A microwave amplifier (,) of the present invention contains such an arrangement that both an inductor (,) and a resistor (,) are loaded in a parallel manner between a source electrode of a field-effect transistor (,) and the ground. Since the inductor (,) has a stray capacitance component (B), the inductor (,) is resonated at a resonant frequency &ldquo;f0&rdquo;. However, since the source electrode of the field-effect transistor (,) is grounded via a resistor (,) connected in parallel to the inductor (,), even when the inductor (,) is opened due to a resonant operation, the field-effect transistor (,) is operated under normal condition. As a result, the operation of the microwave amplifier (,) is stabilized.

Microwave amplifier

A phase shifter includes first and second single pole double throw switches, a low-pass filter, and a high-pass filter. The first switch has an input terminal and first and second output terminals, and the second switch has first and second input terminals and an output terminal. The low-pass filter is interposed between the first output terminal of the first switch and the first input terminal of the second switch and includes FETs as capacitors. The high-pass filter is interposed between the second output terminal of the first switch and the second input terminal of the second switch and includes a plurality of FETs as capacitors. The input terminal of first switch and the output terminal of the second switch are an input terminal and an output terminal of the phase shifter, respectively. Each of the high-pass filter and the low-pass filter produces two different phase quantities by the on-off switching of the FETs. Therefore, four different phase quantities are obtained in the phase shifter, i.e., two different phase shift quantities are realized in the phase shifter.

Phase shifter

A variable attenuation microwave attenuator includes input and output terminals, a high-pass filter having an electrical length of 90.degree. and transmitting signals with frequencies higher than a cut-off frequency, a first variable resistor connected between the input terminal and an input end of the high-pass filter, and a second variable resistor connected between an output end of the high-pass filter and the output terminal, wherein input signals applied to the input terminal are attenuated by the first and second variable resistors before and after the high-pass filter. Therefore, the variable attenuator can be a lumped parameter circuit, i.e., the high-pass filter including two inductors and a capacitor, without using a transmission line as in the prior art device, so that the size of the device is significantly reduced. Further, since the resistance values of the first and second variable resistors do not change discretely but change continuously, a lot of different values of attenuation can be obtained with high precision. As a result, the gain (attenuation amount) can be controlled with high precision.

Variable attenuation microwave attenuator

A microwave switch circuit includes a first impedance conversion circuit, one end of which is connected to an input terminal; a resonance circuit connected between an output of the first impedance conversion circuit and ground and including a parallel connection of a field effect transistor and a resonance inductor; and a second impedance conversion circuit connected between the output of the first impedance conversion circuit and an output terminal. One microwave switch circuit may be connected between an antenna terminal and a signal input terminal and another microwave switch circuit may be connected between the antenna terminal and a signal receiving terminal. The microwave switch circuit output terminal and input terminal may have an impedance of 50 .OMEGA. and the output of the first impedance conversion circuit may have an impedance lower than 50 .OMEGA.. The microwave switch circuit may include one-fourth wavelength transmission lines as the first and second impedance conversion circuits. Consequently, the maximum allowable value of the incident power is increased and withstand power is increased in an antenna switch circuit.

Microwave switch circuit and an antenna apparatus

A switched line phase shifter includes at least three transmission lines having different electrical lengths disposed between an input terminal and an output terminal and connectable in parallel to each other, at least three input side FET switches for connecting and disconnecting the input terminal and the input ends of the transmission lines, and at least three output side FET switches for connecting and disconnecting the output terminal and the output ends of the transmission lines. As many signal transmission paths as transmission lines are produced between the input terminal and the output terminal by controlling the input side and the output side FET switches. When one of the signal transmission paths is selected as a reference and a signal is transmitted through the remaining at least two signal transmission paths, at least two different phase shift quantities are obtained in the phase shifter.

Switched line phase shifter

A distributed amplifier includes an input side circuit including a plurality of distributed constant lines connected in series between an input terminal and ground and a plurality of source-grounded FETs for switching operation having drains connected to respective junctions of the distributed constant lines, an output side circuit including a plurality of distributed constant lines connected in series between an output terminal and ground, and a plurality of source-grounded amplifier FETs having gates connected to respective junctions of the distributed constant lines of the input side circuit via capacitors and drains connected to junctions of the distributed constant lines of the output side circuit. In this structure, since the input side circuit also serves as a distributed switch, when a T/R module is fabricated using the distributed amplifier, it is not necessary to add a distributed switch for controlling signal input and output, so that the chip size of the T/R module is reduced compared to the conventional T/R module. In addition, the signal transmission loss is reduced.

Distributed amplifier and bidirectional amplifier

A switched line type 90.degree. phase shifter includes two single pole double throw switches, a reference transmission line having an electrical length of .alpha. connected between output terminals of the first and the second single pole double throw switches, a phase difference producing transmission line having an electrical length of (90.degree.+.alpha.) at a usage frequency, connected between other output terminals of the first and the second single pole double throw switches, and a phase inverting circuit switchablely connected for serial connection to and between two parts of the reference transmission line, which two parts produce the entirety of the reference transmission line, the one terminal of the first single pole double throw switch is an input terminal of the entire terminal and one terminal of the second single pole double throw switch is an output terminal.

90 degree phase shifter

A loaded line phase shifter includes a semiconductor substrate; a main transmission line one-quarter wavelength long disposed on the semiconductor substrate; loaded lines connected to opposite ends of the main line; first and second FETs with drain electrodes connected to the other ends of the loaded lines and grounded source electrodes; and a resonant circuit including a third FET and an inductor connected between the drain electrodes of said first and second FETs. A desired phase shift quantity of the phase shifter is determined by the characteristic impedance of the main line, the reactance components of the loaded lines, and the off-capacitances of the FETs. When the resonant circuit is closed in this structure, the susceptance of the loaded lines and the first and second FETs is equal to zero, resulting in a phase shift quantity equivalent to half of the phase shift quantity obtained when the resonant circuit is opened. Therefore, two different phase shift quantities are achieved in one phase shifter, resulting in a small-sized multiple-bit phase shifter.

Multiple bit loaded line phase shifter

A reflection phase shifter includes a 3 dB directional coupler having opposite first and second ends, a reflection circuit connected between the first and second ends of the 3 dB directional coupler, a first resonant circuit connected between a node connecting the first end of the 3 dB directional coupler and the reflection circuit and ground, and a second resonant circuit connected between a node connecting the second end of the 3 dB directional coupler and the reflection circuit and ground. Each resonant circuit comprises an FET and an inductor connected between source and drain electrodes of the FET. In this reflection phase shifter, when the resonant circuits are open, the first and second ends of the 3 dB directional coupler are connected to the reflection circuit. On other hand, when the resonant circuits are short-circuited, the first and second ends of the 3 dB directional coupler are grounded. As a result, three different phases, i.e., two different phase shift quantities, are attained in one reflection phase shifter.

Growing community of inventors

Itami, Japan

Kazuhiko Nakahara