Showing papers by "Raytheon published in 1977"

In situ processing of organic ore bodies

Abstract: A method and apparatus for fracturing and/or heating subsurface formations wherein an alternating current electric field is produced in the frequency range between 100 kilohertz and 100 meghertz between electrodes spaced apart in the formation and a radio frequency generator supplying a voltage between said lines with suitable loading structures tuned to the frequency of the generator to resonate the electrodes as a parallel wire transmission line which is terminated in an open circuit and produces a standing wave having a voltage node at the end of the line.

In situ radio frequency selective heating process

Abstract: The process and apparatus for extracting the products of kerogen in situ from an oil shale body by supplying energy selectively to the kerogen by high frequency electric fields in the frequency range between 100 kilohertz and 1000 megahertz at an intensity which heats the kerogen to a temperature range between 250° C. and 500° C. to allow pyrolysis of the kerogen prior to substantial heat transfer to the surrounding mineral portions of the oil shale.

Integrated circuit fusing technique

Abstract: A fusing technique whereby a fuse is fabricated upon a substrate by integrated circuit techniques. Three or more layers of chemically dissimilar metals are deposited upon the region where the fuse is to be formed. The top layers are then etched away from the region where the fusible link is to be formed leaving the lower two layers, the top one of which forms the actual fusible link. The lower layer is then etched away leaving the fusible link suspended from the underlying substrate. The current necessary to cause such a fuse to blow is consistent from fuse to fuse since the physical dimensions of the fusible link can accurately be controlled with the integrated circuit techniques used and, since the fusible link is not in contact with the substrate, the rate at which heat is conducted away from the fusible link cannot vary from fuse to fuse. The method is used to advantage in microwave power and oscillator diode circuits such as those used in phased array radar systems and in read only memories and memory reconfiguration applications, as well as other semiconductor fusing applications.

Platinum film resistor device

Abstract: A platinum film resistor device and method for making the same. A layer of quartz, deposited upon an insulative substrate preferably silicon, is sputter etched at high power levels to produce etch pits in the surface thereof. A layer of platinum is then deposited over the quartz layer by first sputtering platinum at high power for a relatively short period of time and then completing the layer by continuing to sputter deposit platinum at a lower power. A second layer of quartz is deposited over the layer of platinum and the second layer of quartz masked and chemically etched away in the regions where portions of the platinum layer are to be removed. The exposed platinum and a portion of the second quartz layer are then sputter etched away leaving the platinum in a predetermined configuration. The platinum is then annealed, the second quartz layer removed above the lead bonding pads, and external leads attached. The device is particularly useful in temperature measuring application.

Radio frequency ring-shaped slot antenna

Abstract: An array antenna is disclosed wherein each one of the antenna elements includes at least two concentric slots formed in a conductive sheet. The conductive sheet is disposed on a dielectric support and a ground plane is found on the opposite surface of such support. The inner one of the slots enables the outer slot to radiate radio frequency energy having a wavelength greater than the circumference of such outer slot. When such antenna includes an additional concentric slot the antenna is adapted to operate over a pair of frequencies separated by greater than twenty percent while enabling the array antenna to have satisfactory grating lobe characteristics.

Electronic and mechanical improvement of the receiving terminal of a free-space microwave power transmission system

Abstract: Significant advancements were made in a number of areas: improved efficiency of basic receiving element at low power density levels, improved resolution and confidence in efficiency measurements mathematical modelling and computer simulation of the receiving element and the design, construction, and testing of an environmentally protected two-plane construction suitable for low cost, highly automated construction of large receiving arrays.

Position and force measuring system

Abstract: A position and force measuring system for determining the coordinates and force applied to a point on a rigid plate or surface fixed to a rigid foundation by means of a flexible support mechanism and at least three spaced apart sensors. The sensors each deliver an output signal which is proportional to the applied force and the coordinates of the force. The output signals are fed into a processor which computes the force and the coordinates at which the force is applied.

Shipboard point defense system and elements therefor

Abstract: A combined defense and navigational system on a naval vessel is disclosed. The disclosed system includes a track-while-scan pulse radar which is controlled to provide either navigational information or tracking information on selected targets. Additionally, the disclosed system includes a plurality of guided missiles, each of which may be vertically launched and directed toward intercept of a selected target either by commands from the track-while-scan radar or from an active guidance system in each such missile.

Viking Radio Occultation Measurements of the Martian Atmosphere and Topography: Primary Mission Coverage

Abstract: Radio occultation measurements were made at approximately 50 locations on Mars with the Viking Orbiter 1 S (2.3 GHz) and X (8.4 GHz) band tracking links during October 1976. The measurements have been used to study the topography and atmosphere of Mars at latitudes ranging from about 75 deg S to 70 deg N. By using the ingress and egress times obtained from the observed limb diffraction effects together with the best ephemerides available for the orbiter and the planet we have determined the surface elevations at the occultation points relative to the reference areoid. The observations agree with Mariner 9 and radar data to within 2 km. The mean atmospheric pressure at the areoid level was found to be 5.9 mbar during the northern midsummer season, a value which agrees quite well with data obtained at the landing sites. By comparing the new electron density measurements with earlier Mariner data we have determined that the temperature and the plasma scale height of the upper atmosphere appear to be functions of solar activity.

Phased power switching system for scanning antenna array

Abstract: A system for a phased array antenna including a set of power amplifiers for amplifying the power of a signal to be transmitted by radiating elements of the antenna. A set of hybrid couplers are connected between the power amplifiers and the radiating elements with individual ones of the hybrid couplers being cross-connected for sharing the power of each amplifier among a set of radiating elements. The coupling of power is selectively varied between the amplifiers and the radiating elements by shifting the phase of the signal applied to each power amplifier.

Current Developments in SAW Oscillator Stability

Abstract: The results reported were obtained with two port delay lines and resonators used in a simple feedback oscillator. The feedback oscillator employed inherently operates with the amplifier in a saturated condition and, therefore, the AM noise is suppressed. Consequently the dominant noise is FM. Generally, it can be concluded that for very narrow-band, or fixed-frequency applications, the resonator-type oscillator will give the best noise performance. For applications where tunability and linearity are important, the delay-line-type oscillator may give the best performance. There have been no significant improvements in oscillator temperature stability. The only two demonstrated materials for temperature stable SAW oscillators are ST-cut quartz and the SiO2/LiTaO3 overlay structure. Aging tests have been going on for the past two-and-a-half years and it has become obvious that the observed aging rates are largely related to cleaning and packaging.

Microwave coffee maker

Abstract: A coffee brewing appliance for making coffee by the drip method and comprising a reservoir containing a thermally controlled valve adapted to open at a predetermined temperature when heated by water in the reservoir which is subjected to microwave radiation allowing water to flow out of the reservoir onto and through coffee grounds in a filter beneath the valve.

Focussed doppler radar

Abstract: An optically focussed laser radar operating with a radiation wavelength of typically ten microns is focussed on an object to be observed. Doppler data is obtained with a continuous wave signal by mixing a reference of the transmitted signal with a signal reflected from airborne scattering centers. The system is particularly useful for clear air turbulence applications wherein aerosols such as dust and pollen serve as the scattering centers for reflecting the radiation. The radar converts to a pulse Doppler system when the depth of field exceeds the desired range resolution.

Near-Orthogonal Basis Functions: A Real Time Fetal ECG Technique

Abstract: A general technique for the real-time extraction of a physiological signal in the presence of well-characterized noise is described using a noninvasive fetal ECG detection system as an example application.

Multilayer interconnected structure for semiconductor integrated circuit

Abstract: A semiconductor integrated circuit structure wherein a first metal interconnecting system is formed on a semiconductor body having active and/or passive elements formed therein. An insulating layer is deposited on the first metal interconnecting system. Apertures are formed in selected regions of such layer and are cleaned in a sealed sputtering chamber. A refractory metal is deposited over the insulating layer and through the apertures onto the first metal interconnecting system in a sealed sputtering chamber. A lead metal is deposited over the refractory metal layer. Selected portions of such refractory metal and lead metal are removed to form a second metal interconnecting system. With such structure and method the surfaces of the first metal interconnecting system which are to be connected to a second metal interconnecting system through the apertures are cleaned of oxides and other contaminates in a sealed sputtering chamber and are then sealed from further contamination by the refractory metal layer. The method improves the electromigration resistance of the second metal interconnecting system because of the presence of the refractory metal layer. Further, the refractory metal layer acts as a barrier layer which reduces interdiffusion between the connected portions of the first and second interconnecting systems. The assurance of good ohmic contact between the connected portions of the interconnecting systems reduces the surface area required for metallization.

Seed heating microwave appliance

Abstract: An appliance for heating seeds, nuts, grains and the like such as popcorn kernels, for example, by means of microwave radiation, comprising a bowl which is transparent to microwave energy and which has in its lower region an area of restricted size for holding unheated seeds in a clump, the area of the bowl above the restricted area being larger to allow heated seeds to expand, and means for directing the microwave energy upon the clump of seeds.

Frequency-domain design of feedback systems for specified insensitivity of time-domain response to parameter variation

Abstract: Frequency-domain design of feedback systems for prescribed insensitivity of response to parameter variation has relied, in the past, on trial-and-error methods of translating sensitivity specifications from time domain to frequency domain. A rational method for such translation is introduced, which enables time-domain specifications to be achieved by known methods of frequency-domain design.

Multiple Gaussian Targets: The Track-on-Jam Problem

Abstract: When a radar with amplitude comparison monopulse arithmetic encounters signals from multiple Gaussian sources it will "point" to the centroid of the incident radiation. The probability density function (pdf) of the monopulse ratio when N independent samples of difference and sum signals are processed in a maximum likelihood receiver is derived. For finite jam-to-noise ratio the estimate has a bias which is independent of N. The variance in the estimate does however depend upon N. Central moments of order less than or equal 2N - 2 exist and are given by a simple formula. Plots of the pdf and its bias and variance for various jam-to-noise ratios, locations of the centroid with respect to the boresight direction, and number of samples processed are presented in the accompanying figures.

Approximate formulas for the thermal resistance of IMPATT diodes compared with computer calculations

Abstract: Two analytical formulas, which allow the thermal resistance to be calculated approximately for layered heat sinks with finite radii, are presented. They are shown to agree closely with finite-difference computer solutions of the steady-state heat equation for typical diode structures. The approximations allow rapid calculations without recourse to a computer.

Concentrated energy microwave appliance

Abstract: An appliance for heating seeds, nuts, grains and the like such as popcorn kernels, for example, by means of microwave radiation, comprising a bowl which is transparent to microwave energy and which has in its lower region an area of restricted size for holding unheated kernels in a clump, the area of the bowl above the restricted area being larger to allow heated kernels to expand, and means for concentrating the microwave energy upon the clump of kernels.

Scintillator crystal radiation detector

Abstract: A radiation detector, particularly suitable for use in computerized tomographic scanning systems, comprising a scintillator crystal having one window surface optically connected with a photodetector, preferably a semiconductor device, and having other surfaces diffused and tapered whereby the window surface is enabled to see all other surfaces so as to provide efficient passage of light photons from the crystal through the polished surface to the photodetector.

Radar system with specialized weighting

Abstract: A radar system including an azimuthally scanned radar wherein the radar receives echo signals during each of a succession of azimuthally scanned directions of the radar receiving beam. Sequences of samples of data of received echo signals are stored with sets of samples relating to a common range being utilized for developing weighting factors for weighting received echo signals as a function of range. Thereby, dynamic fluctuations in signals strength because of clutter are reduced.

Samarium-cobalt magnet with grain growth inhibited SmCo5 crystals

Abstract: Permanent magnets formed from rare earth cobalt compounds have high energy products. One rare earth cobalt composition, formulated by metallurgical sintering techniques, is a composition of a rare earth and cobalt such as samarium and cobalt containing about 37.2 weight per cent samarium which corresponds to 60 proportions of SmCo 5 for each 40 proportions of Sm 2 Co 7 . This composition is an excellent permanent magnet having an energy product at least as high as 15 × 10 6 gauss-oersteds and up to 20 × 10 6 gauss-oersteds or higher. SmCo 5 contains roughly 33.8 weight per cent samarium, and Sm 2 Co 7 about 42.2 weight per cent samarium; I have found that samarium-cobalt materials containing samarium between about 36.5 weight per cent and about 38 weight per cent are preferred and can be developed into magnets of greatly improved properties. The samarium-cobalt magnet of this invention is basically comprised of crystals of SmCo 5 and Sm 2 Co 7 wherein the SmCo 5 crystals are surrounded by growth-inhibiting materials and are not larger than single domain size.

Humidity Threshold Variations for Dendrite Growth on Hybrid Substrates

Abstract: The investigation of black-box failures, which occurred during operational temperature cycling, revealed that the failures were caused by a dendritic like growth of gold between metallization paths on hybrid micro-circuit substrates. The hybrids had successfully passed the level B screening tests required by MIL-STD-883. Subsequent investigation revealed that tests to determine the presence of water vapor in the hybrid packages could not consistently detect parts which contained dendrites. This fact led to the initiation of a series of tests designed to determine and quantify the levels of moisture and/or contamination required to promote the growth of dendrites.

Comments on "Integral equation formulation for probe corrected far-field reconstruction from measurements on a cylinder"

Abstract: A novel and numerically efficient method of far-field evaluation from measurements taken on a cylinder is based on the representation of both the antenna and the probe fields as superpositions of plane waves. A system of two integral equations are established whose unknown functions are the azimuthal and elevation components of the antenna pattern and whose known terms are the set of measurement data taken with two different probes-the second probe in most practical instances being simply the same probe with a different geometrical orientation. The equations express the known data-for each angular position of the antenna under measurement-as the integrals of the products of the corresponding components of the unknown antenna and known probe patterns multiplied by a phase term. The convolutional nature of the integral equations makes their solutions straightforward. If, as is virtually always the case, the probe has small or moderate size so that the axis of rotation of the antenna mount is in the far field of the probe, the intervention of asymptotic techniques makes the solution numerically very efficient. The agreement of calculated and experimental patterns is excellent.

Cavity backed slot antenna

Abstract: A radio frequency antenna having a flared, discontinuous slot formed on one surface of a dielectric support structure and a feed formed on the opposite surface of such structure. The feed is disposed across a narrow portion of the slot. A housing having a cavity formed therein is provided. The dielectric support is disposed on the housing over the cavity. The cavity has a conductive wall, or deflective plate, disposed beneath a wide portion of the slot. The effects of the feed and the slot-deflection plate combine to provide a flush-mountable antenna having a cardioid-shaped radiation pattern.

Method of operating synthetic aperture radar

Abstract: A method, and apparatus for performing the method, of compensating for the effects of Doppler accelerations due to the orientation of the beam in a squinted synthetic aperture radar used for mapping terrain underlying an aircraft are described. According to the disclosed method, compensation is achieved by calculating the Doppler frequency shifts to be experienced by echo signals from points on the terrain to be mapped and then, in accordance with such calculations, varying the pulse repetition frequency of the squinted synthetic aperture radar to eliminate the effects of Doppler acceleration from the echo signals.

Surface wave device having enhanced reflectivity gratings

Abstract: Surface acoustic wave devices are disclosed which have enhanced reflectivity gratings with conductive stripes between grooves in the substrate or conductive stripes within the grooves. For lithium niobate substrates, aluminum stripes coupled together and positioned between grooves or unconnected and positioned within the grooves are preferred. For quartz substrates, gold stripes within the grooves are used. Methods for fabricating such structures are also disclosed.

Edge enhancement with incoherent optics.

Abstract: A new approach to optical signal processing has recently been introduced by Gorlitz and Lanzl, Lohmann, and Rhodes. One of the important features of the new approach, the use of a frequency offset, had been previously proposed by Macovski in a related context. This Communication is a first report on independent results in this area and is largely confined to experimental results, with a full account to follow. Operations like edge enhancement are apparently ruled out in incoherent imaging systems because of the constraints on OTFs implied by positive PSFs. The new idea is to employ a pupil plane mask in an imaging system, thereby creating a desired filter response on the unconstrained frequency offset Fig. 1. Top: if a copy of this mask is overlaid the original and shifted so the annulus is centered about the circular hole, the opaque disk in the center of the annulus is just big enough to eclipse the hole.