US Government As Represented by the Secretary of the Army

Thomas R AuCoin

Roger J Malik

Samuel Dixon

Melvin J Wade

Abraham Schwartz

Raymond L Ross

A microwave mixer suitable for millimeter wave radar applications. A semi-insulating gallium arsenide dielectric waveguide structure contains an embedded planar doped barrier (PDB) structure as a non-linear mixing element. The local oscillator (LO) signal is guided to the PDB structure via a coplanar type waveguide. The radio frequency (RF) signal is guided to the PDB structure via an image guide and a microstrip circuit serves to transmit the intermediate frequency (IF).

Harmonically pumped monolithic planar doped barrier mixer

A passive millimeter wave image guide power limiter comprising a length of ielectric transmission line or waveguide for millimeter wave frequencies located on a relatively thin conductive ground plane forming thereby an image guide and including a planar doped barrier diode structure formed in the dielectric transmission line with the planar doped barrier structure being integrally grown in a slot milled in the constituent material, i.e. gallium arsenide, of the waveguide transversely across the width dimension thereof so as to be oriented perpendicular to the flow of RF power being propagated along its length dimension. The planar doped barrier structure becomes conductive at a predetermined power level to reflect any further incident RF power back toward the power source.

Monolithic planar doped barrier limiter

Disclosed is an epitaxial layer field effect transistor having a planar dd barrier gate formed on an n-type semiconductor planar channel region between drain and source terminals formed on the surface of the channel region. The semiconductor channel region is fabricated on a semiconductor substrate, preferably GaAs and being separated therefrom by one or more semiconductor planar buffer regions. The planar doped barrier gate comprises an n.sup.+ -.pi.-p.sup.+ -.pi. structure grown by molecular beam epitaxy over the n-type channel region. Application of an electrical potential to the gate modulates the channel charge depletion in the semiconductor channel region underlying the gate causing a variation in the channel conductance laterally between the source and drain terminals.

Planar doped barrier gate field effect transistor

Single crystals of alpha aluminum phosphate of high crystal perfection are rown from seeded solutions of aluminum orthophosphate and orthophosphoric acid in such a manner as to provide direct visual observation of the crystal growth process and allow precise determination of nucleation and growth kinetics. The method involves sealing the seeded solution in clear quartz ampules, inserting the ampules into a precisely temperature controlled silicone oil bath, increasing the temperature of the silicone oil bath from ambient temperature to approximately 150 degrees C. over a three hour period, programming the temperature of the bath upward at the rate of 0.1 to 2.0 degrees C. per day for periods up to sixty days, and removing the quartz ampules from the silicone oil bath and quickly cooling and removing the crystals.

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Ocean, NJ, United States of America

Thomas R AuCoin