Itt Corporation

Itt Industries, Inc.

Tyco Electronics Logistics Ag

Itt Gallium Arsenide Technology Center, a Division of Itt Corporation

Her Majesty the Queen in Right of Canada, As Represented by the Minister

M/a -com, Inc.

Cobham Defense Electronic Systems Corporation

Itt Gallium Arsenide Technology Center

Inder J Bahl

Edward L Griffin

Dain Curtis Miller

David A Willems

Michael D Pollman

Prakash Bhartia

James R Griffiths

Gary K Lewis

The invention provides a novel broadband power limiter having improved frequency characteristics and power capacity, suitable for use with GaAs low-noise amplifier circuits. The power limiter includes a shunt diode circuit and two impedance transformers. The first transformer is a step-down impedance transformer connected between the shunt diode circuit and the input to the limiter, and the second transformer is a step-up impedance transformer connected between the shunt diode circuit and the output of the limiter. The invention further provides a method for limiting the power of an input signal, comprising the steps of: transforming the input signal from the input impedance to an intermediate impedance; shunting a portion of the input signal to ground; and transforming a remaining portion of the input signal from the intermediate impedance to an output impedance. The invention further provides a novel impedance transformer suitable for use in the broadband power limiter and a method for providing such an impedance transformer.

Ultra broadband 10-W CW integrated limiter

An ultra broadband traveling wave divider/combiner (TWD/C) with a two section power splitter with an isolation resistor connected in series with a capacitor across the outputs of each set of transmission lines in the first and second sections. The TWD/C may be formed on a GaAs substrate in MMIC realization. The transmission lines may be formed using microstrip lines on a dielectric. A capacitor may be used with an input impedance step down unit to increase the bandwidth of the TWD/C.

Ultra broadband traveling wave divider/combiner

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 monolithic inductor device is disclosed which typically includes a substrate. The improvement includes a layer of dielectric material disposed over the substrate. A first inductor pattern disposed on the substrate and a second inductor pattern disposed on the dielectric layer. The inductor patterns are coupled together to form a single inductive element, which has reduced dissipation losses and an improved frequency response due to the dielectric material.

High Q compact inductors for monolithic integrated circuit applications

A coupler device is disclosed which has an improved structure. The structure includes a substrate and, input ports and output ports disposed over the substrate. A plurality of inductors and capacitors are further included, which are arranged in a predetermined configuration and coupled between the ports. A layer of dielectric material is also disposed between the inductors and substrate which improves performance by reducing the dissipation losses and enhancing the frequency response of the coupler.

Compact 90.degree. monolithic GaAs coupler for wireless applications

An improved microwave feedthru apparatus is disclosed which provides enhanced performance over the 1-20 GHz frequency range. In its preferred embodiment the apparatus will be used to transmit microwave signals into and out of monolithic microwave integrated circuit (MMIC) packages. The apparatus utilizes a coplanar waveguide (CPW) transmission line section to guide the microwave signal through the wall of the package, substantially free of any in band resonance effects.

Microwave feedthrough apparatus

A power amplifier for microwave frequencies utilizes a FET device operating from a common voltage source. The voltage source has the positive terminal coupled to the drain electrode of the FET. The gate electrode of the FET is adapted to receive a RF signal while the source electrode of the FET includes a voltage limiting diode that is in parallel across the source impedance. In operation the extra current required from the voltage source during power amplification is passed through the diode and the FET source bypass capacitor. This results in the FET source voltage remaining relatively constant to enable improved power and gain operation.

Self biased power amplifier employing FETs

A capacitor element for an integrated circuit comprises a thin layer of dielectric material laminarly disposed between first and second layers of electrically conductive material. Each of the layers has n sides, where n is an even intergergreater than four. Preferably, each layer of the capacitor, and therefore the capacitor itself, is shaped as an equiangular polygon. Although, the capacitor may be configured as a hexagon, a decagon, etc., an octagonal configuration is preferred. By eliminating the 90 feed bend, substantial reductions in discontinuity reactances are obtained. The capacitor element may be provided as an element of a hybrid or a monolithic circuit. When the capacitor element is employed as an element of a microwave circuit, the first conductive layer is deposited on a substrate of a semi-insulating material such as gallium arsenide. The dielectric layer may be formed from silicon nitride, silicon dioxide, silica, or tantalum pentoxide, depending upon the specific capacitance required by the application.

Multiple port thin film capacitor

A coupled line structure for microwave signals employs a gallium-arsenide substrate having an embedded metallic line located on a surface of the substrate. The surface of the substrate is covered with a thin dielectric layer and at least another metallic line is positioned on the dielectric layer and parallel to the embedded line with a portion of the lines overlapping one another for coupling. A third line can also be disposed on the dielectric layer which line is parallel to the other lines and where the embedded line is connected by a via hole to one of the lines on the dielectric.

Broadband tight coupled microstrip line structures

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

An N-way redundant switch is implemented through the use of serial and parallel redundancy for providing redundancy in both ON and OFF operating modes.

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Roanoke, VA, United States of America

Inder J Bahl