Mitsubishi Denki Kabushiki Kaisha

Mitsubishi Electric Corporation

Tohoku University

Mitsubishi Denki Kabushiki

Tadashi Takagi

Noriharu Suematsu

Yukio Ikeda

Shuji Urasaki

Kenichi Miyaguchi

Morishige Hieda

Gen Toyoshima

Kazutomi Mori

Yoji Isota

Kiyoharu Seino

Moriyasu Miyazaki

Masatake Hangai

Tamotsu Nishino

Fumio Takeda

Michiaki Kasahara

Kenichi Maeda

Teruyuki Shimura

Kazuhiko Nakahara

Yukihisa Yoshida

Kazuyoshi Inami

Mitsuru Mochizuki

Masayoshi Ono

Hiroyuki Joba

Norio Takeuchi

Hiroshi Ikematsu

Hiromasa Nakaguro

Mikio Hatamoto

Youji Isota

Kenji Itoh

Koji Yamanaka

Masatoshi Nakayama

Yoshinori Takahashi

Akinori Fujimura

Takeshi Miura

Shintaro Shinjo

Fumio Ishizu

Mitsuhiro Shimozawa

Hiroaki Nagano

Masaomi Tsuru

Kenichi Horiguchi

Kenji Kawakami

Shinnosuke Soda

Yasushi Sogabe

Takatoshi Katsura

Kousei Maemura

Eiji Taniguchi

Kazuhisa Yamauchi

Haruyasu Senda

Takayuki Ikushima

Kazuo Tsubouchi

Shintarou Shinjo

Masahiro Kamiyama

Chiemi Sawaumi

Hiroyuki Nakase

Suguru Kameda

Satoshi Hamano

Norihiro Yunoue

Hideki Hatakeyama

Katsuhisa Uno

Shoichi Oshima

A transmission device () includes: a series/parallel converter (); an MSK modulator () for modulating a signal on a channel basis; a D/A converter (); a frequency converter () for conversion into different carrier frequencies; a synchronization circuit (); an amplifier (); a multiplexer () for multiplexing amplification signals; and an antenna (). A reception device () includes: an antenna (); a demultiplexer (); a frequency converter () for converting signal demultiplexed on a channel basis into a baseband frequency; a low-pass filter () for removing a higher-harmonic component of the signal; an A/D converter (); a digital filter () for extracting a main wave component from the digital signal; a sampling point detection circuit () for detecting a sampling point from the main wave component; an MSK demodulator () for reproducing and demodulating a symbol point based on detection information by an interpolation process; and a parallel/series converter () for restoring an original signal from the demodulated signal.

Radio communication system

A switch circuit includes: a first input and output terminal; a first inductor connected with the first input and output terminal; a capacitor connected with the first inductor; a second input and output terminal connected with the capacitor; a first MEMS switch connected with one end of the capacitor; a second MEMS switch connected with the other end of the capacitor; and a second inductor connected between the first MEMS switch and the second MEMS switch, and satisfies a relationship of f=1/(2&#x3c0;&#x221a;CL)=1/(2&#x3c0;&#x221a;CL), where Lis an inductance of the first inductor, Lis an inductance of the second inductor, C is a capacitance of the capacitor, and f is a use frequency.

Switch circuit

A phase-shifting circuit includes: a first parallel circuit which is connected across input and output terminals of a high frequency signal, composed of a first inductor and a first switching element that exhibits a through state in an ON state and a capacitive property in an OFF state, and produces parallel resonance at a prescribed frequency when the first switching element is in the OFF state; a series circuit composed of a second inductor and a third inductor and connected in parallel with the first parallel circuit; a capacitor having its first terminal connected to a point of connection of the second and third inductors; and a second parallel circuit which is connected across a second terminal of the capacitor and a ground, composed of a fourth inductor and a second switching element that exhibits a through state in an ON state and a capacitive property in an OFF state, and produces parallel resonance at a prescribed frequency when the second switching element is in the OFF state. The phase-shifting circuit establishes by switching an operation mode of setting the first switching element at the ON state and the second switching element at the OFF state, or an operation mode of setting the first switching element at the OFF state and the second switching element at the ON state.

Phase-shifting circuit and multibit phase shifter

Provided is a small-size phase shift circuit having a broad band characteristic. The phase shift circuit includes: a first switching element for switching between a through path and a capacitance capacity; a second switching element for switching the capacitance capacity for the through path and the ground; and a first and a second inductor having inductance. One end of the first switching element is connected to one end of the second switching element by the first inductor while the other ends of the first and the second switching element are connected to each other by the second inductor. One end of the first switching element is connected to a high-frequency signal input terminal while the other end of the first switching element is connected to a high-frequency signal output terminal. Thus, it is possible to constitute a phase device satisfying a predetermined condition.

Phase shift circuit, high frequency switch, and phase shifter

A phase shift circuit and a phase shifter are achieved which are small in size and wide in bandwidth. The phase shift circuit includes a capacitor, and a series circuit composed of a switching element which exhibits capacitivity when it is in an off-state and an inductor connected in series with this switching element, the series circuit being connected in parallel with the capacitor. The capacitor and one terminal of the series circuit are connected with a high frequency signal input/output terminal, and the other terminal thereof is connected with ground.

Phase shift circuit and phase shifter

A phase shifter includes an FEThaving its drain electrode connected to an input/output terminal; and FEThaving its drain electrode connected to the source electrode of the FETand its source electrode connected to an input/output terminal; and FEThaving its drain electrode connected to the source electrode of the FET; and an inductorhaving its first terminal connected to the source electrode of the FETand its second terminal connected to a ground. It can reduce the insertion loss by narrowing the gate width of the FET, and carries out the phase shift of a high-frequency signal with suppressing the reflection.

Phase shifter and multibit phase shifter

In a multi-layer substrate module receiving from an external earth node supply of a reference potential for grounding, a plurality of ground lines are provided respectively corresponding to a plurality of internal circuits. Moreover, a common node for coupling the ground lines is provided in an insulating layer of the multi-layer substrate module. The common node is electrically coupled to the earth node through a ground pin terminal shared by the plurality of internal circuits. Preferably, the common node is provided in the lowest insulating layer of the multi-layer substrate module. Thus, parasitic inductance of the portion through which an earth current flows, that is, the portion common to the plurality of internal circuits, can be suppressed with a small number of ground pin terminals. Accordingly, the inflow phenomenon of the earth current between the plurality of internal circuits is prevented, enabling stable operation.

Multilayer substrate module and portable wireless terminal

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 high frequency amplifier in which a common emitter bipolar transistor is used, and in that a constant current source and a constant voltage source are switched to apply a DC bias to a base terminal of the bipolar transistor in accordance with a power level of a high frequency signal input to the bipolar transistor or a power level of a high frequency signal output therefrom, and a frequency mixer in that a DC bias is applied to a base of at least one of a bipolar transistor for the input of a high frequency signal and a bipolar transistor for the input of a local oscillation wave by using a configuration for applying the DC bias to a base of an amplifying bipolar transistor employed in the high frequency amplifier.

High frequency amplifier and frequency mixer

Between resistors and an NPN bipolar transistor are interposed PNP bipolar transistors forming a current mirror that uses a collector current of the NPN bipolar transistor as a reference current, and determines a collector current of an NPN bipolar transistor . This makes possible to design a size ratio A of the PNP bipolar transistors so as to approximate a voltage drop &Dgr;Vb to a value close to zero, and to suppress the voltage drop &Dgr;Vb of the base voltage Vb accordingly to achieve a high power output and high efficiency when a high frequency input signal Pin increases and generates a base rectified current.

High-frequency amplifier

A miniaturized phase shifter and a multi-bit phase shifter are provided, in which filters are constructed using capacitors at FET pinch-off and pass phase can be shifted by turning the FET on and off, the phase shifter including: a first FET having a drain electrode connected to an input terminal and a source electrode connected to an output terminal; a second FET, in which one of a drain electrode and a source electrode thereof is connected to the source electrode of the first FET and the other is connected to ground via a first inductor; and a third FET, in which one of a drain electrode and a source electrode thereof is connected to the drain electrode of the first FET and the other is connected to ground via a second inductor.

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

Semiconductor circuitry comprises a transistor pair (,) consists of a transistor having a base electrode to which a first signal is applied, and another transistor having a base electrode to which a signal having a phase opposite to that of the first signal is applied, the collector electrodes of those transistors being connected to each other and the emitter electrodes of the transistors being connected to each other, a third transistor (,) connected between a common emitter of the transistor pair and a ground potential and having a base electrode to which a second signal is applied, an output load (,) connected between a common collector of the transistor pair and a power supply (Vcc), and an output circuit for furnishing a third signal from the common collector of the transistor pair, thereby suppressing generation of any even-order higher harmonic of a local oscillation signal when the semiconductor circuitry operates from a low voltage.

Semiconductor circuitry

A feedforward amplifier which includes a distortion detector, a distortion eliminator, an error power extractor, a first level detector and a first controller. The error power extractor extracts output error power due to variations in the distortion eliminator by combining the output signal from the distortion eliminator with the signal from a first linear signal path in the distortion detector in opposite phases. The first level detector detects the output error power extracted by the error power extractor, and the first controller controls a first variable attenuator and a first phase shifter which are interposed in the distortion eliminator such that the output error power is maintained at zero. This can solve a problem of a conventional feedforward amplifier in that the power level of the pilot signal must be increased to heighten the detection sensitivity of the pilot signal because the detection level of the pilot signal becomes minimum at an optimum operation point, and that the increasing power of the pilot signal degrades the communication quality of a system employing the conventional feedforward amplifier.

Feedforward amplifier with improved characteristics without using pilot

A microwave power amplifier having n stages (n is an integer of at least two), which uses bipolar transistors as amplifying elements. Grounded electrodes, bias applying methods, and bias values of the bipolar transistors of the respective stages are set so that phase rotations of output powers of bipolar transistors of m stages (m is an integer of 1.ltoreq.m.ltoreq.n-1) among the n stages are canceled by phase rotation of at least one of the other bipolar transistors of the (n-m) stages. Therefore, the total phase rotation of the power amplifier can be neutralized, resulting in a microwave power amplifier having excellent distortion characteristics.

Microwave power amplifier

Growing community of inventors

Tokyo, Japan

Tadashi Takagi