Hughes Aircraft Company

Itt Corporation

Itt Industries, Inc.

M/a -com, Inc.

Tyco Electronics Logistics Ag

Itt Gallium Arsenide Technology Center

Edward L Griffin

Inder J Bahl

Frederick A Young

Dain Curtis Miller

Harvey M Endler

Robert A Sadler

David A Willems

Richard C Landis

Louis W Hendrick

Arthur E Geissberger

Michael D Pollman

Inder G Bahl

A planar MESFET transistor includes a plurality of FET elements. Each FET element includes a doped planar channel, and source and drain coupled to the ends of the channel. A gate conductor extends over a portion of the channel at a location lying between the source and drain, a first predetermined distance from the drain. A field plate is connected to the gate conductor, and extends toward the drain a second predetermined distance, isolated from the channel except at its gate conductor connection by a dielectric material.

Field-plate MESFET

Disclosed is an improved field effect transistor (FET) employing both a metal-semiconductor (MES) gate and a metal-insulator-semiconductor (MIS) gate, which FET is particularly useful to provide amplification at microwave frequencies. The use of the MIS gate with appropriate biasing allows the carrier density within a selected portion of the device's channel region to be controlled. The carrier density control increases the breakdown voltage of the FET and enables the FET to be operated with higher maximum channel current and a higher drain to source voltage. As a result, higher output power is provided as compared to prior art MESFET devices of a similar size. Also disclosed is an amplifier circuit including the MES/MIS FET of the preset invention, which amplifier circuit further includes means coupled to the MES/MIS FET for dividing a high frequency input signal to provide a first divided portion and a second divided portion. The first divided portion is applied to the MES gate while the second divided portion is applied to the MIS gate. The second portion operates as a time varying bias voltage to control carrier density within the channel portion of the MES/MIS FET and thereby control performance parameters such as breakdown voltage and maximum available channel current.

MES/MIS FET

Disclosed is an improved field effect transistor (FET) employing both a metal-semiconductor (MES) gate and a metal-insulator-semiconductor (MIS) gate, which FET is particularly useful to provide amplification at microwave frequencies. The use of the MIS gate with appropriate biasing allows the carrier density within a selected portion of the device's channel region to be controlled. The carrier density control increases the breakdown voltage of the FET and enables the FET to be operated with higher maximum channel current and a higher drain to source voltage. As a result, higher output power is provided as compared to prior art MESFET devices of a similar size. Also disclosed is an amplifier circuit including the MES/MIS FET of the present invention, which amplifier circuit further includes means coupled to the MES/MIS FET for dividing a high frequency input signal to provide a first divided portion and a second divided portion. The first divided portion is applied to the MES gate while the second divided portion is applied to the MIS gate. The second portion operates as a time varying bias voltage to control carrier density within the channel portion of the MES/MIS FET and thereby control performance parameters such as breakdown voltage and maximum available channel current.

MES/MIS FET with split-gate RF input

A microstrip line device is disclosed of the type which typically includes a strip conductor disposed on the top of a substrate. The device further includes a layer of dielectric material disposed between the strip conductor and the substrate for reducing the dissipation loss in these devices. In order to accomplish this, the dielectric layer has a dielectric constant which is less than the dielectric constant of the substrate.

Low loss ridged microstrip line for monolithic microwave integrated

A high efficiency harmonic injection power amplifier has a power amplifier circuit, and at least a second-harmonic termination circuit which is coupled in parallel with the power amplifier circuit so to sample a small portion of the input signal and to inject into the power output signal an amplified harmonic signal which is phase-shifted for proper harmonic termination. The second-harmonic termination circuit includes a frequency multiplier for multiplying the frequency of the sampled input signal to twice the fundamental frequency, i.e., to 2f.sub.o, an amplifier for amplifying the 2f.sub.o signal to the level of the corresponding harmonic component of the power amplifier output signal, and a phase shifter for shifting the phase of the second-harmonic signal for proper harmonic termination. Additional harmonic termination circuits may be provided for terminating third- and higher-order harmonics.

High efficiency harmonic injection power amplifier

A self-aligned gate (SAG) transistor or FET is described which transistor overcomes several disadvantages of the prior art for making SAG field-effect transistors. The disadvantages noted above result from the fact that current SAG FET's have a symmetrical structure, with n+ regions on either side of the gate electrode. This invention provides a means of masking off a region on the drain side of the gate electrode before performing an n+ implant, so that the n+ implanted region is asymmetrical on the two sides of the gate electrode. This has the desired beneficial effect of reducing the parasitic source resistance, without the deleterious effects on gate-drain breakdown voltage, gate-drain capacitance, and output resistance that invariably accompany a high doping level on the drain side of the gate. Using this technique, substantially increased performance can be obtained from a self-aligned FET.

Method of making self-aligned field-effect transistor

A semiconductor chip housing provides hermetic sealing and appropriate electrical characteristics for use at high frequencies. The housing comprises a substrate in which the chip is mounted and a cylindrical tube having a top cover and extending above the substrate which impinges on a base and thus hermetically seals the chip. Microthin leads extend from the substrate periphery to the chip. The leads carrying high frequency signals have notches therein to compensate for the impedance introduced by the tube and to enable the microstrip to present a constant impedance at high frequencies throughout its length.

Semiconductor chip housing

A substrate for mounting electronic devices is provided with a capacitive coupler as an interconnecting means. The coupler comprises two partially co-extensive conductors surrounded by a shield. The substrate is made from a plurality of superimposed layers, each layer consisting of a dielectric, or a conductive material, or strips of conductive material separated by the dielectric to form a preselected profile.

Coaxial shielded directional microwave coupler

An electromagnetic filter assembly comprises a transmission line electromagnetically coupled to a dual mode resonator having a means for differentially tuning the two modes. The filter may be incorporated in a microwave integrated circuit, and the tuning means may be a movable dielectric slab asymmetrically disposed on the resonator.

MIC Dual mode ring resonator filter

A tri-mode spherical cavity microwave filter comprising two tandemly disposed generally spherical bodies each of which defines a spherical cavity which supports three identical, mutually orthogonal modes of electromagnetic energy, a cavity coupling aperture connecting the cavities, a plurality of cavity tuning holes, and a plurality of coupling tuning holes. One of the spherical cavities has an input aperture, and another has an output aperture. The cavity tuning holes and coupling tuning holes are adapted to receive cavity tuners and coupling tuners, respectively.

Spherical cavity microwave filter

There are herein described evanescent mode filters each of which include a hollow waveguide, wherein a plurality of resonators are disposed, the resonators including loading structures such as tuning screws, for example, wherein at least one of the loading structures is angularly disposed, relative to the axis of the waveguide, with respect to others of the loading structures to reduce the length of the filter and/or to provide internal bridge couplings.

Evanescent mode filter

A folded end-coupled general response TE.sub.011 filter is herein described which achieves all bridge couplings necessary for general bandpass response in a particularly convenient two-tier overlapping structure, where all couplings are made in a single removable iris, and where probe and/or slot couplings are used to achieve coupling of either sign.

Folded end-coupled general response filter

An active microwave filter for use in both bandpass and notch filter applications is herein described, the filter incorporating a distributed resonator to which is coupled an amplifier which provides a positive feedback and cancels the net dissipation in the resonator.

Q Enhanced resonator

A waveguide filter is herein described that employs a resonator ordering which allows a direct realization of all canonical couplings while retaining the advantages of a standard dual mode filter, the filter including a reflective plate in one end cavity and both input and output ports in the other end cavity, where one of the ports is a shunt port in a sidewall of the cavity structure and the other port is a coupling slot in the outer end wall.

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Roanoke, VA, United States of America

Edward L Griffin