Abstract: A broad band, balanced microwave component, such as an amplifier, includes an input Lange coupler having a first center frequency and an output Lange coupler having a second center frequency. The center frequencies of the two Lange couplers are offset or the coupling is different so that at least one of the cross-over points of the input Lange coupler is offset in frequency from both the cross-over points of the output Lange coupler. The pair of Lange couplers so offset in frequency yields no more than one peak in gain which is readily equalized by single-ended amplifiers within the balanced amplifier.

Abstract: A high frequency band-pass filter which includes a single resonator or a plurality of resonators adapted to pass a high frequency signal of a predetermined frequency band region, and an active element device electrically coupled with one or the plurality of the resonators so as to present a negative resistance when the resonator is in a resonant state.

Abstract: An amplifying circuit for amplifying a bipotential input signal, including an insulating housing having a conductive input contact mounted on the housing and adapted to engage a human body so that the bipotential input signal applied to the contact; a lead amplifier having inverting and non-inverting inputs, one of which is coupled to the input contact, and an output; first and second diodes connected in parallel inverse polarity across the inputs of the lead amplifier; third and fourth diodes connected in parallel inverse polarity from the inverting input of the lead amplifier to a circuit common potential; and an output resistor connected from the inverting input to the output of the lead amplifier. Portions of the input contact are surrounded by a voltage drive shield connected to the output of the lead amplifier.

Abstract: In a circuit arrangement comprising a three port isolator (21) which has input, output, and dummy ports (33, 22, and 23), an admittance element (41 to 43) is connected at a position or positions selected between the input and the output ports, between the output and the dummy ports, and between the dummy and the input ports. When the isolator comprises a strip line conductor having branches connected to the input, the output, and the dummy ports, the admittance element may be an extension or extensions of the branches. The output port is connected to an amplifier (14) directly or through an inductance element (34). The connection of the admittance element makes it unnecessary to connect a matching circuit which is otherwise essential between the isolator and the amplifier.

Abstract: Apparatus and method for generating and controlling the electric field within the cavity of a particle beam accelerator. A power splitter divides a common drive signal into separate branches each driving separate RF amplifiers. The output of each amplifier is coupled, through a circulator, to a separate input launcher within the cavity. The high Q of the cavity causes the signal from each launcher to combine to form an undistorted field pattern within the cavity regardless of small amplitude and phase differences at each launcher. Total power control is maintained by changing the phase in one or more of the separate branches, or by chopping the power applied to the amplifiers in the controlled branches. To improve efficiency, the input launchers in branches which are turned off by the chopping technique may be shorted to ground during the turned off interval.

Abstract: A broadband, monolithic integrated-circuit power divider/combiner circuit utilizing gallium arsenide field-effect transistors configured as distributed amplifiers. Two distributed amplifiers include a common merged transmission line element which divides/combines the input signal(s).

Abstract: An RF power amplifier for delivering power to a load including a first quadrature hybrid coupler driving two class C amplifiers operating with high input compression, a second quadrature hybrid coupler coupled to the outputs of the amplifiers, an attenuator, and a phase shifter. An impedance mismatch by the load causes phase-pulling of the amplifiers which reduces output to the load. This is compensated for by feeding an error signal, indicating the magnitude and phase of the phase-pulling of the two amplifiers, from the second quadrature hybrid coupler through the attenuator and the phase shifter back to the first quadrature hybrid coupler. The attenuated and phase shifted error signal adds to or is subtracted from the input signals to the two amplifiers. Therefore, one of the two amplifiers is driven with more signal and the other amplifier is driven with less signal to phase-push the two amplifiers to compensate for the phase-pulling to thereby increase the output to the load.

Abstract: A microwave circuit for combining the high output power of two phase and amplitude controllable amplifiers (e.g. magnetron amplifiers) is described. The circuit uses a "Magic T" circuit to reduce the magnitude of the amplified power which must be dissipated by a low-power ferrite circulator connected between the input signal source and the Magic T. Phase and amplitude comparators are used to control the amplifiers so that they may be combined in the Magic T.

Abstract: A first multi-port hybrid coupler is formed by n2.sup.n-1 (where n is an integer equal to or greater than 2) hybrid couplers alone, which are divided into n stages, each including 2.sup.n-1 hybrid couplers. A signal input to any one of N (=2.sup.n) input terminals of the first stage is distributed equally to N output terminals of the nth stage. The N output terminals of the nth stage of the first multi-port hybrid coupler are connected to N amplifiers at the input side thereof, respectively, and the N amplifiers are connected at the output side to a second multi-port hybrid coupler. The second multi-port hybrid coupler is identical in construction with the first multi-port hybrid coupler, but its input terminals and output terminals are reverse from those of the latter and the input terminals of the second multi-port hybrid coupler are connected to the N amplifiers in an order reverse from the order of arrangement of the output terminals of the first multi-port hybrid coupler.

Abstract: A packaging technique for radio-frequency circuits, such as feed-forward amplifiers, in which a single ground plane is formed between active components of the circuit and a circuit board bearing passive components of the circuit. The ground plane comprises a metallized face of the circuit board and a metal heat sink attached to each active component. The assembly, including the circuit board, heat sinks and active and passive components, is supported on a ledge in the walls of a metal housing, such that heat is conducted laterally through the ground plane and directly into the walls of the housing. The walls of the housing, including an intermediate wall between active amplifier components, also serve to isolate the active components from each other and from the environment. The plane also serves to isolate the active components from the passive ones.

Abstract: A broad-band impedance-matching device for an RF vacuum tube power amplifier incorporates a circuit having multiple inductors and capacitors interconnected in an impedance-matching circuit, said circuit having a low impedance input and high impedance output and made up of a plurality of series connected inductors and capacitors. Impedance transformation is performed in a number of small steps, which enables the use of a much lower cue than would be necessary if the impedance transformation were done in a single step. The arrangement produces an impedance transformation which holds over a relatively broad band width, making in unnecessary for any fine tuning of the network.

Abstract: A phase modulation circuit to provide at an output terminal an output signal controllably shifted from 0.degree. to 360.degree. relative to an input signal provided at an input terminal includes a first 90.degree. coupler connected between the input terminal and second and third 90.degree. couplers, four gain controllable amplifiers, fourth and fifth 90.degree. couplers and an in phase combiner with its output connected to the output terminal. Two of the amplifiers are connected between the second and fourth couplers. The additional amplifiers are connected between the third and fifth couplers. The fourth and fifth couplers are connected to the inputs of the in-phase combiner. The gain through the various amplifiers is adjusted to control the amount of phase shift through the circuit.

Abstract: A distributed power amplifier includes a plurality of field effect transistors (FETS), each one of such FETS having gate, drain and source electrodes, such FETS having cascaded gate electrodes and cascaded drain electrodes successively coupled between an input terminal and an output terminal. The gate electrode of each one of the successively coupled FETS is coupled to the input terminal through a corresponding one of a plurality of capacitors, and a common bias source through one of a corresponding plurality of high impedance bias paths. Since the gate electrodes of each FET are coupled to the input terminal through a capacitor, the coupling capacitor in combination with the inherent capacitance of each FET provides a potential divider into each gate electrode. Therefore, the power fed to each gate electrode is selected by selecting the value of capacitance for the coupling capacitors.

Abstract: The signal to be amplified is applied to a quadrature coupler which splits the signal equally to provide two output signals in phase quadrature. The quadrature signals are amplified equally, which generates a second harmonic in each of the signals 180 degrees out of phase. The amplified signals are combined in an in-phase power divider to provide a single amplified output signal wherein the out-of-phase second harmonic signals cancel.

Abstract: A microwave power amplifier/combiner which is composed of .pi./2 hybrid coupler. This microwave power amplifier/combiner is constructed by associating a .pi./2 phase shifter with the .pi./2 hybrid coupler to form a 2-amplifier/combiner having a single input/output port and employing the 2-amplifier/combiner as one unit. 2.sup.N -amplifier/combiner can be constructed by employing a desired number of the unit 2-amplifier/combiner. According to this amplifier/combiner, the microwave power amplifier/combiner which combines the outputs of a large number of power amplifiers can be combined by employing a small number of .pi./2 hybrid coupler.

Abstract: An intermediate frequency preamplifier of a microwave radio receiver includes an amplifier circuit having a negative feedback path including a directional coupler constituted by two transformers. One port of the directional coupler is terminated with a complex impedance, producing a controlled mis-match, which is adjustable to optimize the input return loss of the amplifier without changing the noise figure of the preamplifier. The amplifier circuit has a low impedance output constituted by a common-collector transistor so that the signal reflected back into the directional coupler by the mis-match does not significantly affect the output of the amplifier.

Abstract: Apparatus is provided for inhibiting the generation of intermodulation products in a radio frequency amplifier coupled to a circulator. A control circuit generates a control signal exhibiting indicia of the amount of isolation provided by the circulator. The control signal is provided to a variable impedance synthesis circuit coupled to the circulation isolation port such that the impedance synthesis circuit exhibits the appropriate impedance to maximize circulation isolation. Intermodulation is thus minimized.

Abstract: An impedance transforming coupler is disclosed which may be used as a power divider or power combiner at microwave frequencies. The power division or power combination ratio is arbitrary, and the impedance transformation ratio is arbitrary. These couplers may be used in a circuit to power-combine amplifiers. The insertion loss of the circuit is low and the bandwidth is improved by an order of two to one over prior art systems which had separate circuits for matching the impedance and providing power combining. The coupler is optimally a branch line coupler having four curved branches a quarter wavelength long at the center frequency. The output ports are 90.degree. out of phase. Simple formulas are given relating the desired admittances of each of the four branches to k, the desired power coupling ratio, and Y, the desired admittance transformation ratio.

Abstract: Input and output electrodes of a microwave, active semiconductor amplifying element are shunted to ground by resistive means having values selected to assure unconditional stability of the semiconductor amplifying element. The resistive means and active element are located in a common semiconductor package having three output terminals respectively connected to input, output and common electrodes of the amplifying element. The resistive means includes, in certain embodiments, first and second resistors respectively shunting the input and common electrodes and output and common electrodes, with values respectively selected to provide relatively high efficiency and low noise characteristics for the amplifying element.

Abstract: This circuit divides power from an input source equally among N different paths, where N is an arbitrary number. These individual path powers can then be amplified separately to take advantage of the full output power ratings for the individual amplifiers, then the outputs from the amplifiers are combined. A combiner circuit, which is the reverse of the divider circuit, then combines the individual powers to a single output. In each of the combiner and divider circuits, the phase angles of the output ports vary from each other by 90 degrees sequentially down the entire chain of N-1 couplers. Each combiner and divider network utilizes N-1 series-connected couplers, preferably interdigitated ones. The interdigitated couplers utilize preselected power division ratios based upon N.

Abstract: The present linear amplifier uses nonlinear components where an input signal with amplitude and phase variations is concurrently applied to a limiter (41) and an envelope detector (42) which provide signals that serve as a carrier signal and a modulating signal, respectively, to a phase modulator comprising two or more linear suppressed-carrier amplitude modulators (50) connected in cascade. The weighted carrier signal and weighted outputs of the even-numbered amplitude modulators (50.sub.2, 50.sub.4, . . . ) are added separately from the weighted outputs of the odd-numbered amplitude modulators (50.sub.1, 50.sub.3, . . . ) to generate two signals which are combined in a quadrature coupler (56). The two outputs of the quadrature coupler are separately amplified in a pair of amplifiers (60, 61) and combined in a second quadrature coupler (64) to provide a substantially linearly amplified output signal of the input signal.

Abstract: The amplifier is intended for use in situations where a considerable distance separates the instrument (for example a piezo-electric transducer) to be monitored and the control room. The amplifier comprises a charge/current converter for converting the charge output of the instrument into a current signal, the charge/current converter being connected to operate as a high impedance current source, a current/voltage converter and a connecting cable connecting the current output of the charge current converter to the input of the current/voltage converter.

Abstract: Occurrence of high field domain in the conventional Gunn diode is prevented by covering a solid body such as a semiconductor element partially or wholly by a dielectric member or by a control element such as a metallic layer coupled reactively with the solid body through a dielectric member, whereby a solid state element having a negative differential conductivity is obtained. Such a type of negative-resistance solid state element, together with its various modes of embodimental construction disclosed herein, affords a superior solid state element which is applicable to amplifiers, oscillators, and the like of millimeter or submillimeter bands.

Abstract: Undesirable odd mode oscillations in coplanar active medium propagation (AMP) devices are suppressed, and transmission of the desired even mode signal is enhanced by placing a planar resistance element beneath the substrate supporting the Gunn epitaxial layer.

Abstract: A negative differential mobility amplifier with a layer of semiconductor material of negative differential mobility. Two electrodes formed by two metallic combs are disposed on the free surface of the layer of semiconductor material. Overlapping fingers of the metallic combs are orthogonal to the propagation direction of the progressive wave and form an ohmic contact with the free surface of the semiconductor layer. The semiconductor layer is deposited onto a first surface of a dielectric substrate. A second surface of the dielectric substrate opposite to the first surface is provided with a metallic plate. The two electrodes are brought in operation to different electrical d.c. biassing potentials by a biassing source and to the high frequency potential of the progressive wave to be amplified. A line of asymetric parallel bands is formed by the metallic plate, the metallic combs, and the dielectric substrate.

Abstract: A solid state power combining apparatus for use in a microwave transmission system. The apparatus includes a distributed amplifier having an input transmission line, an output transmission line, and a plurality of amplifiers connected between the input and output transmission lines at quarter wavelength intervals. The phase relationship between the traveling waves placed on the output transmission line from the amplifiers is such that the waves placed on the output transmission line by the amplifiers in the direction toward an output terminal add and the waves placed on the output transmission line by adjacent amplifiers in the direction away from the output terminal cancel each other.Also, a solid state power combining apparatus wherein a plurality of oscillators are connected between input and output transmission lines at quarter wavelength intervals.

Abstract: A hollow cylinder that has a permittivity greater than the permittivity of air is coaxially disposed within a waveguide with the proximal end of the cylinder coplanar with one end of the waveguide. The cylinder has a metal clad surface wherein a plurality of tapered slots that are narrowest at the proximal end of the cylinder and widest at the distal end thereof. The slots are coupled to respective amplification devices, thereby causing the waveguide to be terminated in an impedance substantially equal to impedances of the devices connected in series. Microwave power is transmitted through the waveguide via propagation of a wave in the TE.sub.01 mode. When the wave propagates to the cylinder, the power is transmitted to the devices via the electric fields within the slots at the proximal end of the cylinder. The wave propagates from the cylinder in response to the power being provided by the devices.

Abstract: Improved interferometric amplification is achieved by separating the input signal in accordance with the signal's projection on two orthogonal reference signals, with one of the reference signals capable of following the instantaneous frequency of the input signal. The separated signals are further separated into constant amplitude variable phase signal pairs defining the projected signals, and the constant amplitude signals are amplified and appropriately combined to form a signal that is in an amplified replica of the input signal.

Abstract: An operational amplifier driver circuit for supplying an undistorted ac signal to a resistive load connected across a balanced pair of twisted transmission lines where the balanced lines have common mode noise signals thereon due to the presence of substantial noise of an external, uncontrolled nature. The driver circuit includes a pair of operational amplifiers interconnected to utilize the common mode noise signals in feedback paths thereof whereby the operational amplifiers are able to operate in their linear ranges even in the presence of high levels of common mode signals on the balanced lines, thereby compensating for the effects of the common mode noise signals on the balanced lines.

Abstract: A cable equalization resonant amplifier circuit for compensating for the signal-attenuation effects of a coaxial cable connected with the amplifier circuit and having a length of up to one-half mile. The gain of the amplifier circuit is matched with the attenuation characteristics of the coaxial cable over a wide range of frequencies by employing an LC resonant circuit with a Q of approximately 1 in the emitter circuit of an amplifying transistor. The gain for the amplifier circuit is established to match the attenuation characteristics of the coaxial cable at low frequencies by an RC circuit coupled with the amplifying transistor and the LC resonant circuit. The maximum or peak desired value of gain for the amplifier circuit at the resonant frequency of the LC resonant circuit is established by a resistor connected in series with the LC resonant circuit and a resistor in the collector circuit of the amplifying transistor.

Abstract: The basic module of a microwave Travelling-Wave Hybrid Junction amplifier (TWHJ) consists of a hybrid junction (0.degree., 180.degree. or 90.degree. hybrid) combined with an appropriate phase-shifting element (.pi./2 element is needed for 0.degree. and 180.degree. hybrids and no element is needed for a 90.degree. hybrid) and three negative conductance circuits terminating three ports of the modified hybrid while the fourth port serves as an input-output port. Because of proper stabilization and matching, the negative conductance circuits are not oscillating but are acting as reflection type amplifiers. Any RF energy applied to the input port of the hybrid is multiply reflected while travelling through the hybrid giving rise to amplified RF energy emerging from the input port of the hybrid junction.

Abstract: A microwave frequency discriminator using a one port active device amplifier including a circulator for coupling an input RF signal of substantially constant power level into the amplifier and an output RF signal out from the amplifier. The discriminator further comprises input and output matching networks connected to the circulator and a detector for generating a D.C. signal as a function of the incoming signal frequency. The input and output impedance matching networks are formed to provide selected impedance conditions to the amplifier such that the power-frequency response of the amplifier varies substantially linearly approximating a frequency discriminator characteristic throughout a predetermined frequency bandwidth.

Abstract: An amplitude stabilized power amplifier having a power splitter for dividing the power of an input signal into a predetermined number of channels, a plurality of amplifier modules for amplifying the power of each of the channels divided by the power splitter, and a power combiner for combining the amplified power signals to provide an amplified output signal. One of the channels of the power splitter is provided with a voltage controlled phase shifter whose phase shift is controlled by an operational amplifier which is responsive to a reference voltage and to the amplified output signal of the power combiner such that the signal in the channel provided with the phase shifter operates to limit the efficiency of the power combiner to maintain a power combiner output signal of constant power with respect to the reference voltage.

Abstract: A bias circuit for a large pulse-width, broad-bandwidth radio-frequency avalanche device comprising a power supply coupled to the device through a bias line. The bias circuit includes a resistive network shunted across the bias line and ground to dampen spurious submicrowave oscillations.

Abstract: A balanced circuit for IMPATT amplifiers and oscillators, which includes at least one pair of anti-series connected matched avalanche diodes electrically connected to the junction of a balanced and an unbalanced transmission line is disclosed. The diodes which are pumped by a large-signal input, are d-c biased to operate in the avalanche condition. A parametrically generated pair of unwanted idler frequencies are separated so that one component of the parametric-pair flows in the balanced line, and the other component flows in the unbalanced line. A central branch of the unbalanced line portion is resistively loaded to overcome the parametrically induced negative resistance of the diodes operating in the avalanche condition, and to suppress all incipient unwanted parametrically generated frequencies. The resistance loading, which is frequency independent, has little effect on the impedance presented to the diodes at the large-signal frequency.

Abstract: An improved low-noise microwave amplifier comprises a circuit arrangement coupled in parallel with a GaAs FET amplifying stage for reducing transmission loss in case of dc power failure or amplifying stage failures. The circuit arrangement comprises two microwave circulators and a microwave isolator connected therebetween.

Abstract: A circuit arrangement for combining high frequency power components with the same frequency which come from amplifiers or generators and are fed to a 90.degree. parallel circuit bridge having two substantially decoupled inputs with the input resistance values of these inputs depending on the output load. The operating voltage supplies of the amplifiers or generators are separately controllable and are controlled so that the output powers of these amplifiers or generators, respectively, remain substantially constant even with mismatching.

Abstract: A microwave frequency discriminator comprising a field effect transistor (FET) amplifier, input and output impedance matching networks and a detector. The FET is biased to generate an output RF signal within a predetermined frequency bandwidth in response to an input RF signal of substantially constant power level. The input and output impedance matching networks are arranged to provide the impedance conditions to shape and linearize the power-frequency response of the FET amplifier throughout the predetermined frequency bandwidth such that the frequency response approximates the linear power-frequency characteristic of a frequency discriminator.

Abstract: A microwave amplifier is disclosed using a nonreciprocal three port junction circulator. The amplifier uses a ferrite circulator having an input port, an output port and a third electrical port. A semiconductor device such as an IMPATT diode having negative resistance is located adjacent and electrically coupled to the third electrical port. The negative resistance of the IMPATT diode combines with the output response of the third electrical port of the circulator to provide power amplification of microwave signals received on the input port.

Abstract: A feed-forward amplifier with an input arranged to receive wide-band signals and an output to supply a linearly amplified version of these has two parallel signal paths arranged between such input and output, one of the signal paths includes a cascade connection of a signal amplifier and a delay network and the second signal path includes an error amplifier, an error extraction circuit having a directional coupler in which an input side has a first pair of conjugate first and second ports and is connected partly to the input of the feed-forward amplifier and partly to an output of the signal amplifier and an output side has a second pair of conjugate third and fourth ports, the fourth port being connected to an input of the error amplifier, and an error injection circuit which has a first and a second input connected to an output of the delay network and to an output of the error amplifier, respectively and an output connected to the output of the feed-forward amplifier, the error extraction circuit having th

Abstract: Disclosed is a broad band amplifier for use as a preamplifier in TV receiving systems and in other applications where broad band amplification is desired. A ferrite directional coupler is used to negatively feed back a portion of the output of an amplifying stage to its input.

Abstract: A circuit for detecting the amplitude of a RF signal propagating along a transmission line. A plurality of rectification circuits, each including a diode and a filter capacitor, are located at different positions along the line. The signal electrodes of the capacitors are connected together to thereby non-additively combine the signals seen at each rectifier.The spacing between the rectifier circuits is carefully selected and will vary with the number of rectifier circuits used. If two rectifiers are employed, the distance therebetween may conveniently be equal to an odd multiple of one-quarter of the wavelength of the driving signal. For this spacing, the combined signal will never fall below the amplitude of the signal produced when the transmission line is terminated with a perfectly matched load. Additionally, the output of the detector will be generally responsive to VSWR. Other RF level detectors having greater numbers of rectifier circuits are also described.

Abstract: As an input and/or an output matching circuit for a transistor, a transistorized high-frequency power amplifier comprises at least one pattern of a conductive material on a sheet of a ferroelectric material placed on a conductive base plate in direct contact therewith. The ferroelectric material is represented by the formula:(1 - x) BaO.xTiO.sub.2,where 0.7 .ltoreq. x < 1.0. Preferably, x .ltoreq. 0.95. The pattern may be in direct contact with the ferroelectric sheet to form a capacitor together with the base plate, a quarter-wavelength impedance transformer, or both. Preferably, the pattern is formed by integrated circuit techniques. An inductor may preferably be provided either by a portion of the pattern with a conventional dielectric material substituted for the ferroelectric material at that part of the sheet which is below the pattern portion or by a chip inductor.

Abstract: A novel microwave power divider is disclosed that is a combination of an ort junction circulator and a novel isolator-mismatch device for each circulator port other than one input port and divides microwave signal power incident to the input port into any desired ratio among the output ports and isolates all the ports from microwave power reflected back toward the divider after being propagated through the divider and thus prevents interaction among line devices, e.g. amplifier units, that are fed by the output ports. Also a novel microwave power combiner is disclosed that is a combination of an N-port junction circulator and a novel isolator-reflector device for each port other than one output port to combine at the one output port identical microwave signals or microwave signals that differ in frequency or phase incident to the isolator-reflector devices. The microwave power combiner, like the microwave power divider, provides isolation among the signal transmission lines.

Abstract: A microwave-integrated-circuit amplifier provides a broadband response in e region of 1-10 GHz. The amplifier includes: a microstrip which provides distributed circuit values for tuning; first and second microwave FETs included in the microstrip and tuned to the upper and lower cutoffs of the bandwidth, respectively; and a non-reciprocal microwave isolator which passes a signal in only one direction and is connected between the first and second microwave FETs.

Abstract: A network characterized at a reference terminal pair by a negative resistance at a frequency near nf.sub.o, where n is an integer greater than one. The network comprises a circuit element characterized by a negative resistance at frequencies in the range f.sub.1 to f.sub.2 where f.sub.1 < f.sub.o < f.sub.2, a passive non-linear network and a filter network for coupling the negative resistance element to the passive non-linear network only at frequencies near f.sub.o and to the reference terminal pair only at frequencies near nf.sub.o. The negative resistance network may be configured with suitable components as a negative resistance amplifier and as an injection locked oscillator.

Abstract: A broad-band microwave amplifier including a semiconductor TRAPATT diode generating a microwave signal at its fundamental, second and third harmonic frequencies. Energy is extracted at the second harmonic frequency and a certain impedance loading is provided at the fundamental and third harmonic frequencies by an open-ended tapered microstrip idler circuit connected in parallel with the diode. The tapered idler circuit also provides a predetermined relatively small rate of change of impedance with respect to frequency changes to obtain a wide instantaneous bandwidth of the amplifier.

Abstract: A high-reliability power amplifier employs passive automatic switching between parallel amplifier channels to provide a constant output power level, which is independent of the failure of an individual channel. The reliability of the amplifier network is improved by amplifying the input signal through parallel channels. Passive switching between channels and a constant level of power output are provided through a hybrid junction.

Abstract: A broadband Impatt diode amplifier for microstrip includes a two-section quarter wavelength impedance transformer. Since the width of one transformer section exceeds a half wavelength, spurious mode resonance is suppressed using a longitudinal slot with an absorbing resistor or by offsetting the transformer sections. A compact configuration combines the power of two microwave diodes over a broad frequency range.

Abstract: An RF power amplifier parallel redundant circuit employs three amplifiers. Under normal operation when all three amplifiers are functioning, the output from a comparator holds a 0.degree., 60.degree. two-bit phase shifter in the 60.degree. position. When anyone of the amplifiers or any pair of amplifiers fail, the comparator output causes the two-bit phase shifter to switch to the 0.degree. position. The system holds the power output constant at one-fourth the value of each individual amplifier for single or double failures. Only one simple switching position operation is required.