Westinghouse Electric Corporation

Northrop Grumman Systems Corporation

Gregory K Sinon

Joseph A Faulkner

Francis W Hopwood

Andrew J Piloto

Scott K Suko

Gary L Ferrell

Patrick G Farrell

Thomas R Turlington

Gerald K Kane

Daniel C Buck

Brian J Misek

John Clarke

John E Kositz

A T/R module including a multilevel, multichip microwave package having a plurality of gallium arsenide monolithic microwave integrated circuit chips (MMICs) implementing RF switching elements, a variable phase shifter, a plurality of RF amplifiers, and gain trim attenuators and which are located on a planar RF assembly. The module's architecture includes shared or common MMIC circuit elements during both transmit and receive operation modes thus reducing the number of MMICs required while at the same time preloading the supply voltage regulator-modulator which supplies DC power to all the MMIC circuits without degrading T/R module efficiency.

Transmit/receive module for planar active apertures

A solid state radar transmitter for use in airborne applications has a modular design which extends into the transmitter. The transmitter is formed of a plurality of power modules the number of which is selected based on the power required for a particular application. For example, two 75 to 100 watt modules may be used for weather radar, while 30 to 60 or more modules may be used for fire control in a military fighter. A radio frequency signal from a stabilized local oscillator is distributed by a splitter to the power modules and a combiner is used to combine the output from the power modules to produce the transmitter output signal. Each power module is formed of parallel connected power amplifiers, preferably formed by GaAs FETs and a power conditioning and control unit. The power conditioning and control unit produces a DC bias across the FETs as desired to produce a particular signal. The transmitter output signals which can be produced in this manner include rectangular, Gaussian on a pedestal and one amplifier at a time for testing purposes.

Modular solid state radar transmitter

Generally, pulsed radar transmitters of the solid-state variety generate rectangularly shaped RF envelope pulses having discontinuities in the rise and fall edges thereof. It has been identified that, while maximizing power radiation efficiency, these sharp rise and fall times additionally provide for excessive energy in the spectral sidelobes about the transmission frequency of the radar signal. This excessive spectral sidelobe energy has been found to degrade the performance of closely operating pulsed radars through mutual interference. The present invention provides for pulse shaping control in a solidstate transmitter of a pulsed radar for reducing the spectral sidelobe energy being transmitted. The control is directed to modulating the shape of the rectangular RF envelope pulses to have substantially continuously rising and falling edges. In the preferred embodiment, a bipolar microwave transistor is coupled, in a common base configuration, cascadedly between low and high power amplification stages of the radar transmitter. A rectangularly pulsed RF power signal conducted through the transistor is modulated in accordance with a preshaped pulsed power supply signal supplied to the transistor coincidently therewith to render a corresponding power output RF pulse envelope substantially free of discontinuities in the rise and fall edges thereof.

Microwave pulse spectrum control

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Dayton, MD, United States of America

Gregory K Sinon