Lockheed Martin Corporation

Unisys Corporation

Loral Corporation

Mahesh Kumar

Michael E Knox

Michael Hanczor

Russel Youmans

Allan S Moskowitz

A radio frequency (RF) integrated circuit includes a first layer of semiconductor material in which a high electron mobility transfer (HEMT) device is formed. A semiconductor heat spreader substrate supports the first layer of semiconductor material. A pair of matching circuits are electrically connected to the HEMT device, wherein the pair of matching circuits are supported on a semiconductor substrate of a semiconductor material different than the semiconductor material of the first semiconductor heat spreader substrate. The first layer of semiconductor material and the first semiconductor heat spreader substrate have a thickness that is less than a second thickness of the semiconductor substrate supporting the pair of matching circuits.

Hybrid microwave integrated circuit

An integrated microwave transistor amplifier includes a AlGaN/GaN active transistor arrangement on a thinned Si 1-mil heat spreader. Elongated, plated-through vias extend from the source portions of the transistor arrangement through the spreader to a thick gold supporting layer. A matching circuit is defined on a four-mil GaAs substrate, also with a thick gold support layer. A stepped heat sink supports the matching circuit and the active transistor with surfaces coplanar. Bond wires interconnect the matching circuit with the gate or drain connections of the transistor.

A power amplifier includes a plurality of signal amplifying stages. An amplitude compensator positioned prior to the ultimate signal amplifying stage equalizes the signal amplitudes in the frequency band of interest to provide a substantially flat frequency response. Fail-soft operation is established by providing switchably redundant amplifiers. When an operating amplifier is detected as failing, automatic switching is performed to replace the failing unit with an identical unit to maintain amplifier operation. High-power amplification is accomplished by splitting a preamplified signal into a plurality of signals, amplifying the lower level signals so obtained, and then recombining the amplified signals.

High power solid state microwave transmitter

In an amplifier for amplifying a pulsed sinusoidal carrier signal, wherein the amplifier employs an amplifier element operative as Class-C with a saturation operation region which increases the sharpness of leading and trailing edges of a rectangular pulse envelope of the pulsed carrier signal for undesirable spectral spreading of energy of the signal, a method of reducing the spectral spreading of the energy employs a modification of the rectangular envelope of the pulsed carrier signal to a trapezoidal envelope. The leading and the trailing edges of the trapezoidal envelope constitute envelopes of sinusoidal waveforms of increasing and decreasing amplitude, respectively. The peak amplitudes of the largest amplitude sinusoidal of the leading and the trailing edges have powers which exceed a power level inducing the saturated operation of the amplifier element such that there is a decrement in incremental power gain by a factor of approximately 3 dB. In the pulse of carrier signal outputted by the amplifier element, the carrier in a central region thereof has a substantially square-wave configuration while, at the leading and the trailing edges, the cycles of the waveform are substantially sinusoidal. A bank of numerous amplifying channels, each of which contains the amplifier element, are fed the modified envelope by a common filter which produces the modification.

Reduction of excessive spectral power distribution from class-C

A solid state amplifier for a microwave transmitter includes a power divider wherein a signal to be amplified is divided into signals of equal signal levels. The equal level signals are respectively coupled to a plurality of amplifiers wherefrom the amplified signals are coupled to a combiner wherein the amplified signals are added and signal sum provided at an output terminal of the combiner. Each of the amplifiers may be comprised of a first stage amplifier, the output signal of which is coupled to a multiplicity of component amplifiers which, in tern, are coupled to a the output terminal of the first stage amplifier via a second power divider wherefrom signals of equal level are provided to the component amplifiers. Bias voltages are provided to the amplifiers via a modularized power supply having some modules with redundant converters.

Solid state amplifier for microwave transmitter

Broadband, monolithic, planar m.times.m and m.times.n transfer switches with diode switching elements are disclosed. Symmetry of the switches maintain equal insertion amplitude and phase performance. Compensation of phase unbalance caused by diode parasitic capacitance is provided by inductors serially coupled between the diodes and the input and output terminals of the transfer switch. Stripline transmission lines are utilized and isolation between the transmission lines is provide in regions of stripline cross over in the plane.

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Hauppauge, NY, United States of America

Mahesh Kumar