Abstract: A hybrid microwave and millimeter wave integrated circuit (MMIC) RF power amplifier includes an integrated circuit in which an amplifier circuit is fabricated and an output impedance matching network comprising metal-insulator-metal (MIM) capacitors mounted on the integrated circuit chip with bonding wire inductors connecting the amplifier circuit with the capacitor elements. The resulting structure has a smaller form factor as compared to conventional power amplifiers employing planar transmission lines and surface mount technology capacitors.

Abstract: A planar dielectric integrated circuit is provided such that energy conversion loss between a planar dielectric line and electronic components is small and that impedance matching between them can be easily obtained. A planar dielectric line is provided by causing two slots to oppose each other with a dielectric plate interposed in between, a slot line and line-conversion conductor patterns are provided in the end portions of the planar dielectric line, and an FET is disposed in such a manner as to be extended over the slot line.

Abstract: A modular high power solid state amplifier and method of assembly, manufacture and use are herein disclosed. The high power amplifier includes a number of amplifiers, a DC board having flexible interconnects, a RF cover including an interlocking RF input, a RF board, a chassis, and a top cover; thereby providing an encased stand-alone solid state amplifier. The solid state components, angled designs, and piggyback topology of the invention provide a compact, efficient, integrated high power amplifier device.

Abstract: An RF power amplifier has a pair of power amplifying elements for receiving first and second distributed signals resulting from distribution of an input signal from the outside and having the characteristics of the same amplitude and opposite phases, performing power amplification with respect to each of the first and second distributed signals that have been received, and outputting the first and second amplified signals and a pair of transmission lines connected correspondingly to the pair of power amplifying elements. The pair of transmission lines have a pair of protruding portions provided at respective edge portions thereof disposed in opposing relation. The pair of protruding portions are disposed in mutually spaced apart and opposing relation to compose a capacitor.

Abstract: A high-frequency circuit device includes a distribution circuit (16) for distributing a signal inputted from a signal input terminal (20) to a plurality of first lines (16b) through a branch portion (16a), a synthetic circuit (18) for combining signals inputted from a plurality of second lines (18b) into one through a combined portion (18a) as an output signal and outputting it from a signal output terminal (22), transistors (14) respectively placed between the first lines (16b) of the distribution circuit (16) and the second lines (18b) of the synthetic circuit (18), and Isolators (24) respectively connected between the transistors (14) and the signal input terminal (20) and between the transistors (14) and the signal output terminal (22).

Abstract: A chip capacitor is arranged on a microstrip conductor forming a microstrip line. The chip capacitor has a dielectric material and electrodes provided on both ends thereof. The electrodes of the chip capacitor are connected to the microstrip conductor. A resonance frequency is decided by the length of the microstrip conductor between the electrodes of the chip capacitor, the dielectric constant and the thickness of the dielectric substrate and the capacitance value of the chip capacitor.

Abstract: FETs 31 to 34 for amplification are connected between an input transmission line 10 and an output transmission line 20. A terminating circuit 29 having a capacitor 292 and a terminating resistor 291 connected in series is connected to an end of the output transmission line 20. To improve a flatness of the gain over a low frequency band, a series-connected circuit having a capacitor 71 and a resistor 61 between the gate of each FET and ground, wherein the design parameter of this circuit is determined so that the impedance thereof is lower in the low frequency band but higher in a high frequency band than the input impedance of each FET.

Abstract: In a high-frequency circuit having bias lines that cross a microstrip line in a plan view, portions of the bias lines are formed on a reverse side of a substrate without forming, in the microstrip line, capacitors required for separating the bias lines from each other as an independent DC line, thus contributing to miniaturizing the high-frequency circuit.

Abstract: A circuit connected between an output terminal of an amplification transistor and a resistor for dealing with higher harmonics included in an output signal transmitted from the amplification transistor, includes (a) a first transmission line having an input terminal electrically connected to the output terminal of the amplification transistor, and having a length of &lgr;/4 wherein &lgr; indicates a wavelength of a fundamental harmonic, (b) a first group of transmission lines, including N transmission lines electrically connected in parallel with one another to an output terminal of the first transmission line, wherein N is an integer equal to or greater than 1, each of the N transmission lines having a length L defined by the following equation: L=&lgr;/4(1+M) (M=1, 2, 3, - - -, N) each of the N transmission lines having an open end, and (c) a second group of transmission lines, including N transmission lines electrically connected in parallel with one another to an output terminal of the

Abstract: A power combiner having a plurality of power amplifiers which are even-numbered, a plurality of series-connected branch circuits for respectively distributing input power to the plurality of power amplifiers, and a plurality of series-connected combiners for combining the respective output power of the plurality of power amplifiers. In the case of any one of such combinations as to equalize electric lengths of transmission lines for connecting between two power amplifiers selected from the plurality of power amplifiers, the combinations each being established by using all of the plurality of power amplifiers once, the electric lengths at which the any one of the combinations are established, take &lgr;/2i (where &lgr;=wavelength of fundamental wave, and i=positive integer).

Abstract: The amplification element is configured by amplifying a multicarrier signal by combining plural carrier waves modulated independently There is disclosed a high-frequency amplifier for amplifying multicarrier signals generated by combining plural carrier waves modulated independently. The amplifier performs a predetermined filtering processing at its output end. An amplification element is also disclosed which is integrated with a circuit for suppressing main components of nonlinear distortions, thus forming an integrated circuit. In electronic appliances, equipments, or systems to which the invention is applied, achievement of reduction in price and size, improvement in reliability, and maintenance and operation being done more efficiently at reduced costs can be accomplished.

Abstract: A microwave amplifier circuit controls the output power thereof depending upon an associated transmitter of a wireless telephone, and a main amplifier transistor and switching transistors of a drain bias controlling circuit are implemented by gallium-arsenide heterojunction field effect transistors so that, even if they are integrated on a single compound semiconductor substrate, the microwave amplifier circuit achieves a high power efficiency over a wide output voltage range.

Abstract: The present invention relates to the traveling-wave amplifier having a &pgr;-type output transmission line structure.

Abstract: A distributed amplifier (40) and a method (100) of operating the distributed amplifier (40) are provided in accordance with the present invention. The distributed amplifier (40) comprises an input transmission line (48), an output transmission line (50) and N amplifier sections (42,44,46) having a transistor (52) connected to the input transmission line (48) and the output transmission line (50).

Abstract: A radio frequency signal output module having a power amplifier and an isolator element is provided in which a radio-frequency output stage can be largely reduced in size and thickness. The radio frequency signal output module comprises a dielectric multilayer substrate; a radio-frequency power amplifier circuit; an isolator element; an impedance matching circuit which is inserted and connected between the radio-frequency power amplifier circuit and the isolator element; and a feedback loop for controlling the gain of the radio-frequency power amplifier circuit. The radio-frequency power amplifier circuit, the isolator element, the impedance matching circuit, and the feedback loop are integrally mounted on the dielectric multilayer substrate, and the feedback loop is branched from the impedance matching circuit, and connected to the radio-frequency power amplifier circuit.

Abstract: A microwave amplifier includes a bias circuit including a micro-strip line and a capacitor for biasing an output line of a FET with a DC voltage, and a filter block implemented by a low-pass-filter or a band-rejection-filter and a capacitor serially connected between the output line and the ground. The filter block passes a beat frequency generated by two of the carrier signals included in the input signal of the FET while maintaining the carrier signals on the output line.

Abstract: Greater levels of microwave and millimeter microwave frequency power is achieved in a new power amplifier structure in which sixteen MMIC amplifiers are supported in a 4×4 row by column matrix and the output (and input) manifold is of a “crazy-H” power combining structure. Even greater output power, on the order of 100 watts at 35 GHz, is achieved by combining multiple numbers of such power amplifier units through a radial combiner.

Abstract: A power distributed amplifier that provides a high power output and a wide bandwidth. The amplifier includes an input and output load termination resistors opposite respective input and output ends of a transmission line. A plurality of amplifying devices are distributed along and electrically connected to the input and output transmission lines. An active feedback loop is connected between the output load termination resistor and the input load termination resistor. The feedback loop includes a regulator connected across the output load resistor and a low pass filter connected between the regulator and the input load termination resistor. The regulator senses voltage across the output load termination resistor and provides a regulated signal to the amplifying devices to control their output currents. The regulator and the line filter combine to provide a reduction in DC bias current sensitivity, RF gain and output power sensitivity over wide process variations.

Abstract: A plurality of amplifying circuits 31 to 34 are connected between input and output transmission circuits 10 and 20 in a forward direction, a bias-T 29 is connected to an output terminal OUT of the transmission circuit 20, and a DC bias voltage VDD1 is applied to the outputs of the amplifying circuits 31 to 34 through the inductor 292 of the circuit 29 and the transmission circuit 20. The opposite end to the output terminal OUT is grounded through a series connection of a terminating resistor R2 and a DC voltage source 30 having an output voltage VDD 2. Since VDD1=VDD1, the DC voltage across the terminating resistor R2 is zero. The inductor 292 may be connected in parallel to the terminating resistor R2 with omitting the bias voltage VDD1.

Abstract: By connecting a grounding conductor pattern directly to a grounding terminal of a field-effect transistor and connecting a series circuit comprising a stabilized resistor and an open-circuit stub having a length equal to quarter of a parallel resonance frequency, undesirable parallel resonance caused by the grounding conductor pattern and the open-circuit stub is suppressed, and a voltage drop in the stabilized resistor is suppressed when a bias voltage is applied to the field-effect transistor. Accordingly, the operation of a microwave amplifier is stabilized.

Abstract: There is disclosed a power amplifier includes an in-phase power splitter generating two split signals from an input signal, and two amplifiers capable of operating in different modes. The split signals are provided as respective inputs to the two amplifiers which are coupled through transmission lines such that as the first amplifier approaches the maximum power it can produce, the output from the second amplifier begins to contribute to the power amplifier output and supplements and modifies the power provided by the first amplifier thereby extending the range of input power over which the power amplifier delivers output power.

Abstract: A multi-stage amplifier for amplifying radio frequency signals includes a first amplifier stage having a first transistor and a second amplifier stage having a second transistor. The first transistor includes a first drain connected to a reference voltage through a first connection circuit. The second transistor includes a second drain connected to a reference voltage through a second connection circuit. The amplifier also includes a first transmission line connecting a portion of the first connection circuit to a portion of the second connection circuit and a resistive element connected in parallel with the first transmission line between the portion of the first connection circuit and the portion of the second connection circuit. The resistive element suppresses oscillation conditions at either of the first and second bias terminals.

Abstract: A multi-stage amplifier for amplifying radio frequency signals includes a first amplifier stage having a first transistor and a second amplifier stage having a second transistor. The first transistor includes a first drain connected to a reference voltage through a first connection circuit. The second transistor includes a second drain connected to a reference voltage through a second connection circuit. The amplifier also includes a first transmission line connecting a portion of the first connection circuit to a portion of the second connection circuit and a resistive element connected in parallel with the first transmission line between the portion of the first connection circuit and the portion of the second connection circuit. The resistive element suppresses oscillation conditions at either of the first and second bias terminals.

Abstract: A power combiner having a plurality of power amplifiers which are even-numbered, a plurality of series-connected branch circuits for respectively distributing input power to the plurality of power amplifiers, and a plurality of series-connected combiners for combining the respective output power of the plurality of power amplifiers. In the case of any one of such combinations as to equalize electric lengths of transmission lines for connecting between two power amplifiers selected from the plurality of power amplifiers, the combinations each being established by using all of the plurality of power amplifiers once, the electric lengths at which the any one of the combinations are established, take &lgr;/2i (where &lgr;=wavelength of fundamental wave, and i=positive integer).

Abstract: A two-dimensional FET array (102) within a Q-band power amplifier module is presented. Array (102) has a plurality of substantially identical one-dimensional FET arrays (106) substantially centered upon a primary axis (130) of two-dimensional array (106) substantially perpendicular to a propagation axis (110) of module (100). Each one-dimensional array (106) is formed of a plurality of FETs (128) substantially centered along a FET axis (134) substantially parallel to propagation axis (110). Each one-dimensional array (106) is proximate and coupled to each of an input bus (136) and an output bus (138), both oriented substantially parallel to propagation axis (110).

Abstract: The present invention provides a new architecture for MMIC circuitry that allows reception of electronically selectable single polarity for simultaneous dual polarity/dual beam signals by phased-array modules. Additionally, an improved phase shifter design that is smaller and requiring fewer electronic components than prior art phase shifters is disclosed. In particular, the phase shifter requires only a single control line for each stage of the phase shifter.

Abstract: A means of connecting a plurality of essentially identical active devices is presented for the purpose of multifunction and multiple function operation. These devices, mounted on a chip, are flip-mounted onto a circuit formed on a base substrate and having large passive elements. Push-pull amplifiers are presented as examples in which the multiple function operation is the combining of amplifiers whose active devices are on a single chip. Electromagnetic coupling, impedance matching and signal transmission are variously provided by the use of strip lines, slotlines, coplanar waveguides, and a slotline converted into a coplanar waveguide.

Abstract: A power amplifier includes a carrier amplifier path and a peaking amplifier path. The carrier amplifier path includes a carrier amplifier (208), and an impedance transforming network (214). The peaking amplifier path includes a peaking amplifier (210), an impedance transforming network (216), and a phase delay quarter wave element (226). The arrangement forms an inverted Doherty combiner where as the nominal impedance at a summing node (230) increases with increased conduction from the peaking amplifier, the load impedance at the output of the carrier amplifier decreases so as to maintain the carrier amplifier at a saturation point as the input signal (232) increases, and results in a reduction of the number of phase delay elements needed over a conventional Doherty approach. In a preferred embodiment the carrier and peaking amplifiers consist of cascaded stages, and are disposed on a common integrated circuit die (304).

Abstract: An umbrella-shaped matching network (10, 14, 16) for matching phase and impedance in a power amplifier (2). The matching network (10, 14, 16) employs rounded corners (22). The rounded corners (22) reduce microwave signal scattering losses, because they are less prone to signal radiation than square corner power combining networks. The matching network (10, 14, 16) includes slits (24) defining separated arms (26). The slits (24) are positioned in such a way that they provide phase and amplitude balance for the signal presented to the amplifiers (2). The slits (24) also prevent current from traveling transversely.

Abstract: FETs 31 to 34 for amplification are connected between an input transmission line 10 and an output transmission line 20. A terminating circuit 29 having a capacitor 292 and a terminating resistor 291 connected in series is connected to an end of the output transmission line 20. To improve a flatness of the gain over a low frequency band, a series-connected circuit having a capacitor 71 and a resistor 61 between the gate of each FET and ground, wherein the design parameter of this circuit is determined so that the impedance thereof is lower in the low frequency band but higher in a high frequency band than the input impedance of each FET.

Abstract: The present invention is a microwave power amplifier using a balanced amplifier. The present invention uses one output port of a hybrid power combiner as a port to detect distortion of the amplifier circuit. To eliminate noise superimposed over a normal signal, the detected distortion is fed forward to the normal amplified signal via an adjustment circuit and directional coupler.

Abstract: A travelling wave power combiner ensures high isolation between power amplifiers and reduces harmonic components caused by non-linearity of each power amplifier. Therefore, the travelling wave power circuit is provided with even-numbered power amplifiers, a plurality of series-connected branch circuits for respectively distributing input power to the even-numbered power amplifiers, and a plurality of series-connected combiners for combining respective output power of the even-numbered power amplifiers. With respect to all of such combinations as to equalize electric lengths of transmission lines for connecting between the power amplifiers to one another, which combinations are established for the plurality of power amplifiers, the electric lengths at which the combinations are established, take &lgr;/2i (where &lgr;=the wavelength of a fundamental wave, and i=positive integer).

Abstract: A power output circuit is constructed as a distributed amplifier (21) with sufficient stages to make it practical for use as part of a transmitter, while also being integratable as part of a single-chip RF transceiver (72).

Abstract: A hybrid radio frequency (RF) power device is provided which comprises: a flange (10) and an arrangement of die blocks (30) disposed about the flange (10), where the arrangement of die blocks (30) has die blocks (30a-30d) organized in a plurality of rows and a plurality columns, where the device may further comprise a substrate (15) disposed between the flange (10) and the arrangement of die blocks (30), and a first die block (30a) connected to a second die block (30b) by a conductor (42c) having a length of half a wavelength.

Abstract: A high frequency power amplifier includes: a pair of power amplifying elements; a power divider, provided in the vicinity of an input terminal of the high frequency power amplifier, for supplying the pair of power amplifying elements with signals, respectively, the signals having an identical amplitude with each other and having reverse phases from each other; and a power synthesizer, provided in the vicinity of an output terminal of the high frequency power amplifier, for synthesizing signals output from the pair of power amplifying elements, the signals having an identical amplitude with each other and having reverse phases from each other.

Abstract: An inductor includes a semiconductor substrate, pairs of pads formed on the semiconductor substrate at predetermined intervals with the pads in a pair spaced apart a predetermined distance, bonding wires connect the pads constituting the corresponding pairs of pads, and metal lines connect pads among the pairs to other pads to form a current path for the inductor. Since the inductor uses bonding wire which has low resistance and can reduce the contact area with chips, the inductor has few parasitic components and a high quality factor in nearly all frequency regions.

Abstract: A power amplifier for microwave signals, the amplifier comprising a plurality of identical transistors, wherein: the grid buses of two adjacent transistors are interconnected by a grid matching circuit; the drain arrays of two adjacent transistors are interconnected by a drain matching circuit; the grid matching circuits are selected in such a manner as to ensure input levels to each transistor that are identical in amplitude and in phase; and the drain matching circuits are selected in such a manner as to present each transistor with optimum power impedance. The amplifier input is on the grid bus of a transistor at one end of the series connection of transistors and the amplifier output is on the drain array of a transistor at the other end of the series connection of transistors. It is thus possible to assemble an arbitrary number of transistors in a power amplifier, while providing an amplifier that occupies a smaller area.

Abstract: By connecting a grounding conductor pattern directly to a grounding terminal of a field-effect transistor and connecting a series circuit comprising a stabilized resistor and an open-circuit stub having a length equal to quarter of a parallel resonance frequency, undesirable parallel resonance caused by the grounding conductor pattern and the open-circuit stub is suppressed, and a voltage drop in the stabilized resistor is suppressed when a bias voltage is applied to the field-effect transistor. Accordingly, the operation of a microwave amplifier is stabilized.

Abstract: A shunt feedback circuit path for use in high frequency amplifiers fabricated as a transmission line coupled to ground at one end and coupled to the shunt feedback transmission line of the amplifier at the other end. The shunt feedback transmission line has a first and second resistive element and a first and second capacitive element. A quarter-wavelength transmission line is used to transform the impedance coupled to one end with respect to the other end. The impedance as seen from one end of the line is a function of the characteristic impedance of the line. Therefore, by selecting the characteristic impedance the transmission line can be used to affect the impedance of the feedback path so the transmission line appears as an inductor of reactance equal to the characteristic impedance of the quarter-wavelength transmission line and reduces the overall effective length of the feedback path.

Abstract: Disclosed herein is a harmonic suppression circuit having a first microstrip line and a second microstrip line each having the same characteristic impedance. One end of the first microstrip line is electrically connected to a transmission line over which a signal having a predetermined frequency is transmitted, and one end of the second microstrip line is grounded. The length of the first microstrip line and the length of the second microstrip line are respectively set to the length corresponding to 1/8 of the wavelength with respect to the predetermined frequency. Series impedance means comprised of capacitance means and inductance means is electrically connected between the other end of the first microstrip line and the other end of the second microstrip line. The reactance of the capacitance means and the reactance of the inductance means at the predetermined frequency are respectively set to 3/4 of the characteristic impedance of each microstrip line.

Abstract: For use with RF circuitry in which a DC bias circuit provides bias voltage is provided to impedance-matched circuitry, a structure is provided, in which a dielectric member, having a high dielectric constant, is selectively placed adjacent to a bias feed line coupled between the DC bias circuit and the remainder of the circuitry, to maintain high RF impedance while reducing impedance at lower frequencies. The invention has particular applicability to RF amplifiers, to be used for amplifying modulated carriers, such as video signals made up of an RF carrier and a lower-frequency modulation. Where the carrier has a predetermined wavelength, the physical length of the bias feed line and the dielectric constant of the dielectric member are chosen such that an effective length of the bias feed line is a quarter of the wavelength of the carrier.

Abstract: Disclosed is a field effect transistor amplifier using a field effect transistor as an amplification device, including a coaxial dielectric resonance device inserted between the input terminal of the amplifier and the input terminal of the amplification device and having a .lambda./2 electrical length and a characteristic impedance lower than the input-side impedance at the input terminal.

Abstract: A power amplifier MMIC has a first stage amplifier circuit having a transistor and matching circuits provided on input and output sides of the transistor; a plurality of final stage transistors connected in parallel; a first line connected between adjacent gates of the plurality of final stage amplifiers; a second line, connected between adjacent drains of the plurality of final stage amplifiers, for correcting an input signal phase shift caused by the presence of the first line; and an output matching circuit connected to one of connection points between the second line and the drains, and wherein an output of the first stage amplifier circuit is coupled to one gate of a final stage transistor whose drain is not connected to the output matching circuit, and the first stage amplifier circuit and the plurality of final stage transistors are arranged longitudinally alongside each other.

Abstract: A distributed amplifier topology with distributed feedback includes a plurality of amplifier stages, each of which includes a FET, MESFET or HEMT. A negative feedback network is provided with each amplifier stage which enables the gain of the distributed amplifier to be reduced by varying the negative feedback. An important aspect of the invention relates to the fact that the gain can be varied with virtually no affect on the bandwidth performance of the product and without significantly affecting the return loss, IP3 and noise figure performance of the device.

Abstract: A new amplifier module construction enhances the manufacturer's ability to repetitively construct multiple copies of millimeter microwave amplifiers having performance characteristics that are consistent with one another, particularly in input VSWR ratio characteristic, and which performance characteristic do not significantly change following any necessary rework of the amplifier module, including any MMIC chip replacement. In this module, a waveguide to microstrip transition is formed of a backshort member that is separate from the metal base or cover and that backshort member is held pressed in place against the substrate by force exerted by the module's cover plate through a spring member against the exterior of the backshort member. The spring member is formed by a resilient compressible gasket.

Abstract: A multicarrier linear RF power amplifier incorporating an improved signal splitter and an improved signal combiner is disclosed. The amplifier comprises a plurality of wedge-shaped amplifier modules. When such modules are radially disposed and abutted against one another, the inwardly facing edges of the modules collectively define a central or axially-located opening. An improved signal splitter, signal combiner, or dual splitter/combiner is advantageously disposed in the axially-located opening. The signal splitter or signal combiner is a conductor arrangement comprising a plurality of equal length conductors radially disposed on a dielectric substrate. The conductor arrangement is advantageously disposed within a suitably-configured housing. The housing is disposed within the axially-located opening.

Abstract: A combined test fixture and spatial-power-combined amplifier includes a base, a first waveguide mounting flange engaged to said base, a second waveguide mounting flange engaged to said base, a waveguide input fixed to said first flange, a waveguide output fixed to said second flange, an amplifier array disposed between said first flange and second flange, said array comprising a plurality of semiconductors for amplifying a signal, and a spacer for spacing apart said semiconductors. A plurality of amplifier cards constitute the array, with the cards being disposed in various arrangements which include a linearly stacked arrangement and radially stacked arrangement. The first and second waveguide mounting flanges are constructed to slide along the base to enable the amplifier array to be easily changed.

Abstract: A method and apparatus for efficiently amplifying input signals includes multiple amplifiers (20, 30). Each amplifier receives a signal from a power divider (12) where the input signal is split with substantially equal phase. Each amplifier drives a load (40) through a parallel coupled line pair (26, 36). The parallel coupled line pairs are preferably implemented in micro-strip or strip line technology. Each amplifier includes gate bias inputs (24, 34) and drain bias inputs (22, 32). The gate bias inputs can be biased equally and the drain bias inputs can be biased equally, resulting in a parallel, power combined, amplifier configuration. Alternately, the drain bias inputs can be staggered, or the gate bias inputs can be staggered to increase efficiency.

Abstract: A frequency-adjustable direct current biasing circuit is disclosed for providing a DC bias voltage or a DC connection to ground for an RF or microwave circuit without substantially affecting the RF or microwave signal of the circuit. The biasing circuit includes a transmission line having a first portion for connection to the RF circuit and a second portion connected to a low-impedance-to-ground structure, such as a bypass capacitor or a DC path to ground. The electrical length between the first and second portions is about 90 degrees. The biasing circuit further includes an open ended tuning stub coupled to the transmission line that has a length that is adjustable. By adjusting the length of the tuning stub, the biasing or grounding circuit can provide better isolation for RF energies at different selected frequencies. Also disclosed herein is a dielectric resonator oscillator (DRO) that uses the frequency-adjustable biasing circuit.

Abstract: A microwave amplifier includes an FET, a DC bias voltage supply circuit, and a beat smoothing circuit. The FET amplifies a microwave signal including a plurality of carrier frequencies that are different from each other. The DC bias voltage supply circuit supplies a DC bias voltage to the FET. The beat smoothing circuit removes a beat frequency generated on a line connected to the FET due to a difference among the plurality of carrier frequencies. The beat smoothing circuit is constituted by a microstrip line having a low impedance with respect to the beat frequency, and a capacitor for short-circuiting to ground the beat frequency output from the filter means.