Abstract: An in-phase power combiner is constructed of a double field-effect transistor having a common drain, first and second gates and first and second sources. The gates are adapted to receive radio frequency signals of powers P1and P2, where P1=P2, to be power combined. The combined power output signal P equal to at least P1+P2 appears at the drain. An alternative power combiner for producing power combination of two unequal power input signals is constructed of a double dual gate FET having, in addition to the above-mentioned elements, third and fourth gates.

Abstract: A predistortion circuit for use with a solid state power amplifier or traveling wave tube amplifier which exhibits phase and amplitude nonlinearities. The predistortion circuit, which produces gain and phase distortion complementary to that of the associated power amplifier, comprises a hybrid circuit for splitting the input signal into two output signals at respective output terminals, the signals having a relative phase difference of 90.degree., a pair of dual gate FETs or other active nonlinear devices each connected to a different one of the two output terminals and a combiner for combining in-phase the outputs of the nonlinear devices. Bias on the nonlinear devices is adjusted to effect, in the predistortion circuit, nonlinearities complementary to those of the power amplifier.

Abstract: A predistortion circuit for a microwave power amplifier which exhibits phase and amplitude nonlinearities and has a small signal gain equal to a. The phase distortion circuit includes a 180.degree. coupler, a first coupler for coupling a given fraction of the input power to the 180.degree. coupler and a second coupler for coupling the given fraction of the power output from the amplifier, reduced by a, to the 180.degree. coupler. The 180.degree. coupler has a difference output port at which a signal appears which corresponds substantially to the difference in phase between the two signals input to the 180.degree. coupler and has a sum port at which a signal appears which corresponds substantially to the sum in amplitude between the two signals input thereto.A phase change circuit and attenuator are coupled between the first coupler and input to the power amplifier. Signals related to the signals produced at the difference port and sum port of the 180.degree.

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 180.degree. hybrid receptive of a fundamental frequency signal which may be adjusted over a range of frequencies produces the fundamental frequency signal at two output ports phased 180.degree. apart. Each of the output ports is coupled to a non-linear active device which produces the fundamental frequency and odd and even harmonics thereof. A 180.degree. and 0.degree. hybrid is coupled to receive at respective input ports the signal from the active devices and to produce at one output port all the odd harmonics and to produce at the other output port all of the even harmonics of the fundamental frequency. The even and odd harmonics of the fundamental frequency appearing at the two output ports of the 0.degree. and 180.degree. hybrid are isolated from one another.

Abstract: A one port-to-M port passive signal power divider circuit (or combiner circuit) where M>2 and .noteq. 2.sup.N, M and N are integers, includes M - 1 two-way in-phase passive power dividers having a signal delay D through each path in one or more delay devices having delay D. Each output of each two-way power divider is coupled to an input of another power divider, a delay line or an output port, the arrangement being such that the delay through all ports of the power divider are equal. In accordance with a further embodiment of the invention the outputs of a passive power divider are connected to two-way switches using active components. The switches under control of a control circuit are utilized to switch the input signal to the power divider to any one of 2.multidot.M output terminals of the switches.

Abstract: A predistortion circuit for a radio frequency power amplifier which has gain and phase shift characteristics that are non-linear as a function of power level of an RF input signal. The circuit includes a dual gate FET, with a drain coupled to the power amplifier. A modulated RF input signal is applied to an inductive matching network which is coupled to the signal gate of the FET. A modulating envelope detected version of the input signal is applied to a video amplifier which is coupled to the FET control gate. The signal applied to the control gate varies the gain of the FET as a function of input signal to compensate for the non-linear gain characteristic of the power amplifier and in conjunction with the matching network causes a phase change of the signal through the predistortion circuit to compensate for the non-linear phase characteristic of the power amplifier.

Abstract: A variable-gain, constant output power amplifier which generates an output rf signal of constant power level in response to an input rf signal of varying power level. The amplifier gain is preadjusted by a plurality of feedforward automatic-gain-control circuits to provide the constant output power. The amplifier comprises five dual-gate MESFET signal-amplifying stages. The first and last stages do not have built-in automatic-gain-control. The first stage is provided for preamplification prior to sampling the input signal, and the last stage is provided for setting the level of the output power externally. The signal at the input of each of the middle three stages is sampled through a coupler and detected and processed at video frequencies to dynamically preadjust the gain of the next signal-amplifying stage.

Abstract: A plurality of FET or other amplifiers are connected between respective outputs of an N output port power divider network and respective inputs of an N input power combining network in a variable power amplifier system. A gate bias is selectively supplied to each of the amplifiers which is either at a first value to cause the amplifier to amplify or at a second value to cause the amplifier to be cut off and therefore to not dissipate any DC power. The number of amplifiers receiving the first potential is determinative of the amount of power amplification of the variable power amplifier.

Abstract: A 0.degree. and 180.degree. hybrid power divider/combiner includes a first quadrature hybrid and two other quadrature hybrids arranged in tandem with one output port of the first hybrid connected to an input port of the tandem arrangement and the other output port thereof connected to a delay of electrical length equal to that of the tandem arrangement. When an input signal is applied to one input port of the first hybrid with the other port terminated, two signals of reduced amplitude which are either in phase or of opposed phase (dependent on which input port receives the input signal) are produced at the output of the tandem arrangement and delay.