Abstract: A plurality of source-grounded transistors (3) are connected in parallel with each other, and a plurality of gate-grounded transistors (4) are connected in parallel with each other. Sources (4s) of the plurality of gate-grounded transistors (4) are connected to drains (3d) of the plurality of source-grounded transistors (3) respectively. Ground pads (5) are connected to sources (3s) of the plurality of source-grounded transistors (3). A plurality of grounding capacitances (6) are connected between gates (4g) of the plurality of gate-grounded transistors (4) and the ground pads (5). The plurality of source-grounded transistors (3) and the plurality of grounding capacitances (6) are alternately arranged between the ground pads (5) and the plurality of gate-grounded transistors (4).

Abstract: An amplifier circuit is configured in such a manner that the withstand voltage between the terminals of a FET 2 (withstand voltage B) is higher than the withstand voltage between the terminals of a FET 1 (withstand voltage A), and that the gate width of the FET 1 (Wg1) is narrower than the gate width of the FET 2 (Wg2). This makes it possible to increase the gain while maintaining high output power. The narrow gate width of the FET 1 (Wg1) connected to an input terminal 3 enables reducing the size of the cascode amplifier.

Abstract: An array antenna apparatus in which an SN ratio is improved. Antenna elements having transmission modules, respectively, are arranged in plurality, wherein the plurality of transmission modules respectively have transmission signal generators that each output a transmission intermediate frequency signal, local oscillation signal generators that each output a local oscillation signal, and transmission mixers that each mix the transmission intermediate frequency signal and the local oscillation signal with each other, thereby to carry out frequency conversion to a transmission high frequency signal. A reference signal source inputs a reference signal to the transmission signal generators and the local oscillation signal generators. The transmission intermediate frequency signal and the local oscillation signal are synchronized with each other by the reference signal.

Abstract: A transmission module including a power supply voltage control unit that sets a power supply voltage to the high frequency amplifier in a variable manner, and a control circuit that controls an amplitude control unit, a phase control unit and the power supply voltage control unit. The control circuit and the power supply voltage control unit control the power supply voltage in accordance with an output power of the high frequency amplifier. The transmission module can carry out not only phase control but also amplitude control in a continuous manner, while suppressing amplitude and phase variation, and a high frequency amplifier in the transmission module is made highly efficient. In addition, a large directional gain, a low side lobe level and a low power consumption are achieved, as a phased array antenna apparatus using a transmission module.

Abstract: A front-end amplifier has an impedance detector that detects an impedance seen looking into an antenna side from a power amplifier from a radio-frequency signal output from the power amplifier and a radio-frequency signal reflected from the antenna, in which a control circuit decides on whether the impedance detected by the impedance detector belongs to a specific region or not, and controls, if the impedance belongs to the specific region, at least one of the bias condition of the power amplifier and the impedance of a variable-matching circuit.

Abstract: A multiport amplifier and a wireless device using the same are obtained in which isolation among output terminals is improved, whereby the quality of communication is improved. The multiport amplifier includes an input hybrid, an output hybrid, a plurality of amplifiers and a plurality of gain and phase control circuits that are inserted between the input hybrid and the output hybrid, a plurality of output coupling circuits that are inserted between the output hybrid and a plurality of output terminals so that they receive output extraction signals corresponding to a plurality of output signals, and a feedback circuit including a frequency selection circuit that is inserted between the plurality of output coupling circuits and the plurality of gain and phase control circuits.

Abstract: A transmission module including a power supply voltage control unit that sets a power supply voltage to the high frequency amplifier in a variable manner, and a control circuit that controls an amplitude control unit, a phase control unit and the power supply voltage control unit. The control circuit and the power supply voltage control unit control the power supply voltage in accordance with an output power of the high frequency amplifier. The transmission module can carry out not only phase control but also amplitude control in a continuous manner, while suppressing amplitude and phase variation, and a high frequency amplifier in the transmission module is made highly efficient. In addition, a large directional gain, a low side lobe level and a low power consumption are achieved, as a phased array antenna apparatus using a transmission module.

Abstract: An array antenna apparatus in which an SN ratio is improved. Antenna elements having transmission modules, respectively, are arranged in plurality, wherein the plurality of transmission modules respectively have transmission signal generators that each output a transmission intermediate frequency signal, local oscillation signal generators that each output a local oscillation signal, and transmission mixers that each mix the transmission intermediate frequency signal and the local oscillation signal with each other, thereby to carry out frequency conversion to a transmission high frequency signal. A reference signal source inputs a reference signal to the transmission signal generators and the local oscillation signal generators. The transmission intermediate frequency signal and the local oscillation signal are synchronized with each other by the reference signal.

Abstract: A multiport amplifier and a wireless device using the same are obtained in which isolation among output terminals is improved, whereby the quality of communication is improved. The multiport amplifier includes an input hybrid, an output hybrid, a plurality of amplifiers and a plurality of gain and phase control circuits that are inserted between the input hybrid and the output hybrid, a plurality of output coupling circuits that are inserted between the output hybrid and a plurality of output terminals so that they receive output extraction signals corresponding to a plurality of output signals, and a feedback circuit including a frequency selection circuit that is inserted between the plurality of output coupling circuits and the plurality of gain and phase control circuits.

Abstract: Provided is a high frequency amplifier including two amplifying elements of different element sizes connected in parallel and switching the amplifying elements in accordance with a level of output power. In particular, the high frequency amplifier includes an output matching circuit for matching to characteristic impedance (50 ohms) both when the output power is high and low, and increasing impedance when the turned-off amplifying element is viewed from a connection node on an output side of the two amplifying elements. Consequently, characteristics such as high output power and high efficiency can be achieved and it is possible to prevent an amplified high frequency signal from passing around to a matching circuit on a turned-off amplifying element side.

Abstract: A high-frequency amplifier is configured in such a manner that a detecting diode 4 and an NPN bipolar transistor 11 of a bias circuit 5 are biased by a common power supply, and that when the amplitude of an envelope signal increases, the bias current supplied from the NPN bipolar transistor 11 to an amplifying element 15 is suppressed following the amplitude of the envelope signal.

Abstract: Provided is a high frequency amplifier including two amplifying elements of different element sizes connected in parallel and switching the amplifying elements in accordance with a level of output power. In particular, the high frequency amplifier includes an output matching circuit for matching to characteristic impedance (50 ohms) both when the output power is high and low, and increasing impedance when the turned-off amplifying element is viewed from a connection node on an output side of the two amplifying elements. Consequently, characteristics such as high output power and high efficiency can be achieved and it is possible to prevent an amplified high frequency signal from passing around to a matching circuit on a turned-off amplifying element side.

Abstract: A high-power amplifier changes matching conditions of an output matching circuit 5 connected between a final stage amplifying element 3 and an output terminal 8 in response to the output power of the amplifying element 3. Thus, the efficiency at low output power can be greatly improved without reducing the efficiency at the maximum output. Besides, since it is not necessary to load a DC-DC converter, an increase in size or cost can be prevented.

Abstract: A high-power amplifier changes matching conditions of an output matching circuit 5 connected between a final stage amplifying element 3 and an output terminal 8 in response to the output power of the amplifying element 3. Thus, the efficiency at low output power can be greatly improved without reducing the efficiency at the maximum output. Besides, since it is not necessary to load a DC-DC converter, an increase in size or cost can be prevented.

Abstract: A high frequency amplifier includes a constant voltage driven amplifier 1 using as its amplifying element a bipolar transistor 7 with its base biased by a constant voltage, and a constant current driven amplifier 2 using as its amplifying element a bipolar transistor 8 with its base biased by a constant current. The idle current of the constant current driven amplifier 2 is set at a low value. In accordance with the idle current, the idle current of the constant voltage driven amplifier 1 is adjusted, and the two amplifiers are combined in parallel.

Abstract: A high frequency amplifier includes a constant voltage driven amplifier 1 using as its amplifying element a bipolar transistor 7 with its base biased by a constant voltage, and a constant current driven amplifier 2 using as its amplifying element a bipolar transistor 8 with its base biased by a constant current. The idle current of the constant current driven amplifier 2 is set at a low value. In accordance with the idle current, the idle current of the constant voltage driven amplifier 1 is adjusted, and the two amplifiers are combined in parallel.

Abstract: The present invention includes: a first main waveguide 1; a T-branch circuit 3 connected thereto; a first low-pass filter 5 connected thereto; a band-pass filter 7 connected to the first T-branch circuit 3; a first converter 8 connected to the first low-pass filter 5 for converting transmission lines between a waveguide and a microwave integrated circuit; an amplifier 10 connected to the first converter and structured by the microwave integrated circuit; a second converter 9 connected thereto for converting transmission lines between a waveguide and the microwave integrated circuit; a second low-pass filter 6 connected thereto; a second T-branch circuit 4 connected to the second low-pass filter and the band-pass filter 7; and a second main waveguide 2 connected to the second T-branch circuit.

Abstract: The present invention includes: a first main waveguide 1; a T-branch circuit 3 connected thereto; a first low-pass filter 5 connected thereto; a band-pass filter 7 connected to the first T-branch circuit 3; a first converter 8 connected to the first low-pass filter 5 for converting transmission lines between a waveguide and a microwave integrated circuit; an amplifier 10 connected to the first converter and structured by the microwave integrated circuit; a second converter 9 connected thereto for converting transmission lines between a waveguide and the microwave integrated circuit; a second low-pass filter 6 connected thereto; a second T-branch circuit 4 connected to the second low-pass filter and the band-pass filter 7; and a second main waveguide 2 connected to the second T-branch circuit.

Abstract: A high-frequency amplifying unit 2 in which a steep gain variation developed according to a change in the amplitude of input high-frequency signal is suppressed is provided. It amplifies an input high-frequency signal with a plurality of transistors 12-1 to 12-N at the same time a measuring circuit 27 measures amplitude of the input high-frequency signal, and a bias control circuit 26 continuously controls a bias applied to each transistors 12-1 to 12-N according to the value of amplitude measured by the measuring circuit 27. Thus it is possible to suppress a steep gain variation produced according to a variation in the amplitude of input high-frequency signal.

Abstract: 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 10, basic HBTs 14 that constitute the multifinger HBT 12 corresponding to the first stage, are each made up of an HBT 14a and an emitter resistor 14b connected to the corresponding emitter of the HBT 14a, whereas basic HBTs 18 that constitute the multifinger HBT 16 corresponding to the output stage, are each comprised of an HBT 18a and a base resistor 18c connected to the corresponding base of the HBT 18a. 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.