Lockheed Martin Corporation

Rf Saw Components, Incorporated

Lockhead Martin Corp.

Lewis Taylor Claiborne

Clinton S Hartmann

Pradip Mitra

Mark A Dodd

Henry Garton Lewis, Jr

Brian Allen Gorin

The present invention provides a system for avoiding code collisions from multiple SAW identification tags and a method of operating such system. In one embodiment the invention provides for (1) focusing an interrogation pulse to within a defined space; and (2) discriminating between coded responses returned from tags located within such defined space.

Anti-collision interrogation pulse focusing system for use with multiple surface acoustic wave identification tags and method of operation thereof

A diffraction grating coupled infrared photodetector for providing high performance detection of infrared radiation is described. The photodetector includes a three-dimensional diffractive resonant optical cavity formed by a diffraction grating that resonates over a range of infrared radiation wavelengths. By placing a limited number of p/n junctions throughout the photodetector, the photodetector thermal noise is reduced due to the reduction in junction area. By retaining signal response and reducing the noise, the sensitivity increases at a given operating temperature when compared to traditional photovoltaic and photoconductive infrared photodetectors up to the background limit. The photodetector device design can be used with a number of semiconductor material systems, can form one- and two-dimensional focal plane arrays, and can readily be tuned for operation in the long wavelength infrared and the very long wavelength infrared where sensitivity and noise improvements are most significant.

Diffraction grating coupled infrared photodetector

A two-color photodetector for detecting two different bands of infrared radiation is described. The photodetector includes either a diffractive resonant optical cavity that resonates at the two colors of interest, or a diffractive resonant optical cavity that resonates at the first color and a vertical resonant optical cavity that resonates at the second color. By placing materials that absorb only one of the two colors at the appropriate locations within the resonate structure, the resultant signals include little cross-talk due to the opposite color. The two-color photodetector finds use in applications covering a wide portion of the infrared spectrum.

Two-color grating coupled infrared photodetector

An antenna array structure is disclosed for use in receiving, transmitting, or transceiving electromagnetic radiation. The antenna array structure includes a first planar substrate with one or more grooves formed therein with at least one secondary planar substrate having an antenna formed thereon placed in one of the grooves in the first substrate. The use of this three-dimensional structure takes advantage of the inherent directionality due to the guidance of electromagnetic radiation by the secondary planar substrate. This antenna array structure provides the advantages of reduced cross talk between adjacent antennae and can readily be produced using standard silicon fabrication techniques.

Integrated circuit mm-wave antenna structure

A hyperspectral radiation detector system collects infrared radiation concurrently from a plurality of adjacent infrared spectral bands. A collector system includes an optical train for receiving the incoming radiation, a disperser for separating the received infrared radiation into multiple adjacent bands of interest and a focal plane array for detecting the individual infrared bands and producing corresponding output signals. The focal plane array is an enhanced quantum well infrared photodetector having multiple physical dimensions of each detector varied in a predetermined manner to alter the frequency of responsivity of the detector to form the multi-band pixels of the received image. The output signals from the array can be processed as required to review selected bands of interest or to determine if certain types of targets are present within the received radiation. The system can be coupled to ground control or other platforms for receiving collection control commands and for returning collected data which may be in compressed form.

Hyperspectral radiation detector

An infrared photocathode comprises an infrared radiation absorbing structure based on multiple quantum well (MQW) material on top of an electron conducting contact layer having a negative electron affinity back surface. In the first photocathode, a top contact layer is etched to form a transmissive diffraction grating to aid photon absorption in the MQW material. In the second photocathode, a plurality of spaced apart MQW structures form a diffraction grating which aids photon absorption in the MQW material.

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Richardson, TX, United States of America

Lewis Taylor Claiborne