Mcdonnell Douglas Corporation

Mcdonnell Douglas Helicopter

Carl A Mentzer

Donald J Berg

Paul T Fisher

Michael C Cates

Henry B Morris

Alex T De La Pena

Gregory J Sapletal

David A Brooker

A measurement chamber which surrounds a target of interest intersected by a line defined by focal points associated with the measurement chamber and which separates and extracts scattered signals from the measurement chamber, includes a chamber having an interior defined by rotation of a nonlinear curve about the line, and first and second focusing elements which couple the scattered signals out of the measurement chamber. According to one aspect of the invention, the measurement chamber further includes first and second absorbing material sections which absorb the scattered signals, and which are disposed proximate to the distal ends of the first and second focusing elements, respectively. Alternatively, a measurement chamber which surrounds a target of interest disposed on the centerline of the measurement chamber and which separates and extracts scattered signals from the measurement chamber, includes a chamber having an interior defined by rotation of first and second non-linear curves about the centerline, and first and second focusing elements which couple the scattered signals out of the measurement chamber. Preferably, the first non-linear curve is a parabola having a focal point located on the centerline, while the second non-linear curve is a parabola having a focal point offset from the centerline by a predetermined offset distance. A corresponding measurement system is also described.

Low radar cross-section (RCS) measurement chamber and associated

A support member for a measurement chamber, which measurement chamber surrounds a target of interest intersected by a line defined by focal points associated with the measurement chamber, and which chamber separates and extracts unwanted scattered signals from the measurement chamber, the measurement chamber including a chamber section having an interior defined by rotation of a nonlinear curve about the line, and first and second focusing elements which couple the scattered signals out of the chamber section, includes a surface for attaching at least one of the target of interest and a source generating signals scattered by the target of interest and a sting element which is coaxial with the line and which is coincident with one of the focal points. According to one aspect of the present invention, the source is attached to the surface and supported by a sting element which is defined a body of rotation about the line. According to another aspect of the present invention, the target of interest, which is disposed between the source and the sting element, is attached to the surface. Preferably, selected surfaces of the support element are covered by radar absorbing material. According to another aspect of the present invention, first and second support elements are provided to support the source and target of interest, respectively. Low RCS measurement chambers and systems are also described.

Low radar cross-section (RCS) support pylon and low RCS measurement

A fiber optic spatial light modulation system which includes a light source which produces source light, an optical fiber bundle which includes a plurality of individual optical fibers, and a spatial light modulator which is interposed between the light source and the optical fiber bundle, and which selectively modulates the amount of the source light coupled into each of the individual optical fibers, wherein the amount of the source light coupled into different ones of the individual optical fibers can be unequal. In the disclosed embodiment, the spatial light modulator is a digital micromirror device which includes an array of micromirrors, a semiconductor memory which includes an array of memory cells, wherein each of the memory cells is associated with a respective one of the micromirrors and stores a bit of binary data, and the system employs a digital microprocessor which executes a desired control algorithm and sends the binary data to appropriate ones of the memory cells to selectively drive the micromirrors into an on position or an off position in accordance with the binary value of the binary data. Each of the individual optical fibers has associated therewith a plurality of micromirrors which are each oriented to couple the source light into the corresponding individual optical fiber when in the on position and to not couple the source light into the corresponding individual optical fiber when in the off position.

Digitally controlled fiber optic light modulation system

A low RCS measurement system includes a measurement chamber which surrounds a target of interest intersected by a line defined by focal points associated with the measurement chamber and which separates and extracts scattered signals from the measurement chamber system, the measurement chamber system including a chamber having an interior defined by rotation of a nonlinear curve about the line, and first and second focusing elements which couple the scattered signals out of the chamber, a signal source which emits signals along the line, wherein the emitted signals interact with the target of interest to thereby produce the undesirable scattered signals and desirable backscattered signals, a source support pylon which supports an output element of the source and which couples the scattered signals out of the chamber, and a target support pylon, which supports the target of interest at one of the focal points, and which is coaxial with the line. The source support pylon includes a body of rotation about the line, and directs the scattered signals into one of the first and second focusing elements. Preferably, output element comprises a parabolic reflector. The source can include the parabolic reflector, a horn antenna and a subreflector, all of which are substantially coaxial with the line or the same elements, where the parabolic reflector intersects the line, while the horn antenna and the subreflector are disposed outside of the measurement chamber and communicate with the parabolic reflector via a window in the measurement chamber wall.

Integrated projector-low radar cross-section (RCS) source support pylon

The microwave absorption performance of a fiber loaded thermoplastic syntactic material is improved by geometrically reshaping the surface into a waffle shape. Starting with a fiber loaded version of thermoplastic syntactic foam, the front face geometry is then modified. Typically, the angle and frequency response is a function of both the front face angle and the skin thickness. These effects are minimized in this concept by using a pyramidal surface in which the field enters the material normal to at least one surface at almost all incident angles. The attenuation is over 20 dB, from S through Ku bands, over a broad angle range of up to 75 degrees off normal. An added benefit is that this system has a rigidity that is suitable for many structural applications.

Thermoplastic syntactic foam waffle absorber

The present invention provides a lighting system including a centralized light source, a plurality of light emitters, and a plurality of fiber optic lines extending between the light source and the light emitters for delivering light therebetween. More particularly, the present invention includes a light source operably coupled to a concentrator for directing light generated by the light source towards an exit end of the concentrator. A fiber optic bundle is secured at its proximal end to the exit end of the concentrator for receiving the light generated by the light source therein. A plurality of sub-bundles diverge from the fiber optic bundle and transport the light from the light generator to a plurality of emitters. The emitters are disposed at various locations of desired illumination and emit the delivered light therefrom.

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Poway, CA, United States of America

Carl A Mentzer