Westinghouse Electric Corporation

Northrop Grumman Systems Corporation

James E Degenford

Daniel C Boire

Harvey C Nathanson

Carl Baldwin Freidhoff

Ronald G Freitag

Marvin Cohn

Thomas J Smith, Jr

J Douglas Adam

F William Hopwood

Daniel C Buck

Dale E Dawson

Soong H Lee

Scott A Imhoff

Howell G Henry

David A Blackwell

Russell R Shaller

An electronically steerable antenna array which includes time delay units connected to individual antenna elements for time delaying a microwave signal to and/or from the antenna elements. Each time delay unit includes small mercury wetted switches for controlling signal flow via a time delay path or a bypass path, through the time delay unit from a signal input to a signal output.

Antenna system using time delays with mercury wetted switches

A switch having spaced apart conductors with a high resistivity gate member therebetween. First and second mercury droplets are respectively connected to the ends of the conductors. When a control signal is applied to the gate member, the mercury droplets are drawn to it and establish electrical connection between the conductors to close the switch. Upon removal of the control signal the mercury droplets separate and assume their initial droplet form thus opening the switch.

Mercury wetted switch

The present invention provides a monolithic superheterodyne detector pixel operable to receive a radio frequency (RF) signal at millimeter wavelength and produce a video output signal with many orders of improved sensitivity when compared with the prior art. This sensitivity improvement is achieved by translating the received RF signal to a intermediate frequency (IF) signal before detection of the video signal. At the lower frequency of the IF signal, monolithic amplification circuitry can be fabricated more easily to provide necessary gain than would be achievable if simple amplification of the RF signal were attempted. Detector pixels constructed in accordance with the invention each contain an antenna for receiving the RF signal. Local oscillator (LO) signal circuitry likewise apply an externally generated LO signal to the pixel. The RF signal and LO signal are then applied by interconnecting conductors to appropriate mixer means to produce the IF signal. An IF amplifier next amplifies the IF signal to a level sufficient for detection of the video output signal by a second detector. In presently preferred embodiments, pixel circuitry is fabricated in microstrip format with impedance matching provided between respective monolithic components. The antenna and local oscillator signal circuitry may each comprise slots defined in the metallized ground plane of the detector substrate. Utilization of a subharmonic mixer permits the external LO signal to be a subharmonic of the 'virtual LO' mixed with the received RF signal. The amplifier may comprise a plurality of cascaded field effect transistor (FET) amplifier stages. The second detector, as well as diodes utilized in the mixer, are preferably Schottky barrier diodes.

Millimeter wavelength energy detector pixel having intermediate

A semiconductor device has material removed from the back of the substrate and a manufacturing process is provided for manufacturing these devices. In the exemplary embodiment, a GaAs FET chip is formed by a process including the step of etching the GaAs substrate from the back of the chip in a defined removal region to reduce the dielectric constant in the region of the source-to-drain path. A buffer layer of differing material provided between the active layers and the substrate prevents etching of the active layers during the removal process. To allow simplified etching patterns, the source-to-drain path may be laid out on the surface of the chip in a variety of patterns, including 'packed' patterns concentrating a large path area in a small surface area of the chip. Optionally, this buffer layer may also be etched away in a further processing step. An insulating layer of material may be added to the back side of the chip in the etched region to increase structural strength, and a pressure relief ventilation path may be provided connecting the removal region to the outside at an edge or at the surface of the chip.

Low-loss semiconductor device and backside etching method for

A hybrid ring structure 180.degree. phase shifting apparatus or device capable of taking a single electrical input signal of predetermined frequency, splitting said signal into two isolated independent output signals utilizing engraving upon the substrate on one side only wherein said device is fully operable and compatible to operate in hybrid micro-electronic functions.

180.degree. hybrid tee

A wideband 180-degree digital phase shifter bit is provided which is operable independently of input rf frequency over a predetermined bandwidth of interest. The phase shifter bit comprises a coupled transmission line segment and a pi network segment, with switching means for alternatively connecting the rf input and rf output first to the coupled transmission line segments, and then to the pi network.

Wideband 180-degree phase shifter bit

A phase inverter generates two signals 180.degree. out-of-phase at microwave frequencies in response to an input microwave signal incorporating a semiconductor substrate such as gallium arsenide, a transistor having a drain, source and gate electrode, an ion-implanted resistor coupled between the drain electrode and a voltage source, a second ion-implanted resistor coupled between the source electrode and ground potential, a compensation network such as a capacitor coupled between the source electrode and ground potential, and a biasing network for establishing a bias voltage on the gate electrode. The phase inverter which may be monolithic overcomes the problem of the size of quarter wavelength slot lines to generate signals with 180.degree. phase relationship.

Monolithic microwave 'split load' phase inverter for push-pull

A power combiner has been described incorporating N transmission lines each having a quarter wavelength or multiple thereof for a frequency within a predetermined frequency range where the input of each transmission line has a resistor coupled thereto with the other ends of the resistors coupled together using inductance and capacitance to compensate for the distances between the resistors to provide a floating node which is low impedance in the predetermined frequency range. A composite amplifier is described on gallium arsenide wherein a power divider and power combiner are coupled to a plurality of MESFET's and wherein each input and output of the power combiner and power divider have a resistive load with respect to the MESFET while including a matching circuit and wherein each input of the combiner has a resistor coupled to a first floating node and each output of the divider has a resistor coupled to a second floating node. The invention overcomes the problem of a composite amplifier where many elemental amplifiers must be driven and their output signals combined at frequencies where the physical layout would provide phase differences such as in a layout of parallel cells on a flat surface of a substrate.

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Ellicott City, MD, United States of America

James E Degenford