Abstract: A modular electronic architecture is provided. In particular, one or more unit sub-arrays providing at least a portion of the antenna radiator elements and supporting circuitry comprising at least part of a phased array antenna are provided. Each unit sub-array includes a first area comprising a rigid circuit board on which one or more antenna radiator elements are formed. In addition, a second area of rigid circuit board material for supporting circuitry is provided. The first and second areas are interconnected to one another by a region of flexible circuit board material having connective traces. Methods for forming unit sub-arrays providing antenna radiator elements and supporting circuitry are also provided. More particularly, a completed unit sub-array may be formed while the associated circuit boards are in a flat or planar condition.

Abstract: The present invention is directed to a laser communication receiver for wireless optical communication. A laser communication receiver includes a diffractive optical element to permit detectors at different spatial locations to detect different wavelengths of the optical signal. An immersion lens may be employed to focus the optical signal to a spot size smaller than the photoactive area of the detector. In one detector configuration, the optical signal is folded by a reflective surface and focused on a plurality of stacked detectors. The present invention further provides a method of manufacturing a detector and immersion lens assembly that provides a high degree of alignment between the lens and the corresponding detector.

Abstract: The present invention is directed to a laser communication receiver for wireless optical communication. A laser communication receiver includes a diffractive optical element to permit detectors at different spatial locations to detect different wavelengths of the optical signal. An immersion lens may be employed to focus the optical signal to a spot size smaller than the photoactive area of the detector. In one detector configuration, the optical signal is folded by a reflective surface and focused on a plurality of stacked detectors. The present invention further provides a method of manufacturing a detector and immersion lens assembly that provides a high degree of alignment between the lens and the corresponding detector.

Abstract: The present invention is directed to a laser communication transmitter and receiver for wireless optical communication. The laser communication transmitter uses a small diameter so correspondingly divergent beam to provide improved bit error rates. A laser communication receiver includes a diffractive optical element to permit detectors at different spatial locations to detect different wavelengths of the optical signal. An immersion lens may be employed to focus the optical signal to a spot size smaller than the photoactive area of the detector.

Abstract: A correlation filter is provided having passbands at wavelengths corresponding to the absorption spectrum of an atmospheric gas of interest. In particular, the correlation filter features narrow, non-linearly spaced passbands having center wavelengths that are correlated to the non-linearly spaced absorption lines of an atmospheric gas. A correlation filter in accordance with an embodiment of the present invention includes a compensation stack having a number of thin film layers, at least some of which have an optical thickness that is not equal to an integer multiple of one-quarter of a wavelength of an absorption line of the gas of interest. The correlation filter may be provided in association with an etalon, or may comprise a number of optical cavities.

Abstract: A high sensitivity, single chip, low light level imaging device is provided. The imaging device of the present invention utilizes sparse color sampling, to maximize the luminance information gathered. In particular, color information is gathered by a small proportion of the pixels included in an image sensor, while the remaining pixels operate at full spectrum sensitivity. The present invention allows the correct hue of objects to be determined, while providing high sensitivity to available luminance information in a scene. The imaging device can include a global near infrared blocking filter that can be selectively placed in the optical path of the device. In addition or alternatively, opaque pixels may be included in the image sensor to correct for errors caused by charge diffusion.

Abstract: A sensor system featuring a field angle compression telescope optical system for measuring atmospheric trace gases is provided. According to an embodiment of the present invention, the telescope optical system condenses the field angle of received light with respect to a cross track plane, while leaving the field angle with respect to an along-track plane uncompressed. Such an anamorphic telescope design provides a wide field of view, while allowing information regarding the altitude or height distribution of a gas to be obtained. According to another embodiment of the present invention, the field angle of received light is compressed by magnifying the received light by a value less than 1.0 in all directions.

Abstract: Dielectric materials having modified dielectric constants and methods for modifying the dielectric constant of a dielectric material are provided. Generally, the dielectric constant of a dielectric material is modified by providing relieved portions within the dielectric material. The relieved portions may comprise holes formed in the dielectric material. In connection with dielectric material that is incorporated into an antenna apparatus, the size and/or arrangement of holes or other relieved portions in the dielectric material can be determined with reference to the operating wavelengths of the antenna apparatus.

Abstract: A high sensitivity, single chip, low light level imaging device is provided. The imaging device of the present invention utilizes sparse color sampling, to maximize the luminance information gathered. In particular, color information is gathered by a small proportion of the pixels included in an image sensor, while the remaining pixels operate at full spectrum sensitivity. The present invention allows the correct hue of objects to be determined, while providing high sensitivity to available luminance information in a scene. In addition, the present invention allows hue information to be ascribed to objects in a scene, even in combination with luminance data collected over a spectrum that includes the near infrared and infrared wavelengths.

Abstract: In accordance with the present invention, a system for separating gas and liquid phases from a mixed phase system is provided. Furthermore, the present invention provides for the reliable separation of liquid and gas phases, regardless of the orientation of the system with respect to a gravitational field, and in low or zero gravity environments. The system of the present invention generally provides a reservoir having a variable volume that is formed from a gas permeable, hydrophobic, microporous, polymer material. Material confined within the reservoir is maintained under pressure, to expel any gases introduced to the interior of the reservoir as part of a mixed phase inlet stream. The liquid phase component of the mixed phase inlet stream may be removed from the reservoir through an outlet located within the reservoir volume.

Abstract: The present invention provides an improved antenna system that, in one embodiment, includes an antenna array comprised of a plurality of elements, each of which is capable of providing a signal. Also included in the improved antenna system is, a multi-beam beamformer for producing two spatially independent overlapping beams from the signals provided by two different subsets of the antenna array. The phase of the two beams is compared to realize an interferometer that can provide high or fine resolution data on the position of an object relative to the antenna system. The amplitude of the two beams can also be compared to obtain coarse data on the position of the object. The beamformer includes a switching network for selecting which elements of the antenna array form the two subsets. This permits, for example, the position of the beams to moved, the baseline of the two beams to be varied, and/or the beam width of the beams to be altered.

Abstract: A radio frequency reconfigurable lens is provided. In particular, a lens comprising at least two opposed frequency selective surface sheets is provided. A relative phase shift may be imparted to an incident radio frequency wave by varying the distance between at least some of the unit cells of a first of the FSS sheets and adjacent unit cells on a second of the FSS sheets. In order to provide a desired phase taper across the width of a lens, and/or to provide different phase shift amounts, pairs of FSS surfaces having controllable columns or rows can be cascaded together. According to an additional aspect of the present invention, radio frequency waves can be scanned by cascading multiple tunable stages. The present invention also provides a radio frequency shutter.

Abstract: A dual band coplanar microstrip interlaced array antenna is provided. The antenna may be confined to a relatively small area, while providing dual band operation with no or minimal grating lobes and losses. According to the present invention, first and second arrays are interlaced with one another to minimize the surface area of the antenna. A maximum spacing between array elements is selected based on the operating wavelengths and scan range for each of the arrays. A first dielectric constant of a material underlying elements of the first array is calculated from the selected element spacing and the operating wavelength of the first array. A second dielectric constant of a material underlying elements of the second array is calculated from the first dielectric constant and the operating frequencies of the first and second arrays. The present invention provides a dual band coplanar microstrip interlaced array antenna capable of efficient operation at two center frequencies.

Abstract: A method and apparatus for maintaining fuel cell cathode air quality are provided. In particular, the method and the apparatus of the present invention provide air filtration that excludes liquids and solids from a fuel cell enclosure. According to one embodiment of the present invention, the fuel cell enclosure can withstand being submerged in water, without allowing contaminants to enter the fuel cell enclosure. The depth at which the fuel cell could be submerged is dependant upon the pore size of the filter membrane. The present invention provides a filter having a gas permeable, hydrophobic, microporous polymer film to exclude material detrimental to the operation of the fuel cell. The invention allows a fuel cell apparatus to be provided that is capable of being submerged in water and exposed to environmental contaminants without damage to the fuel cell.

Abstract: The present invention provides an antenna system including a body for use in determining N unknown parameters values relating to an object located in the vicinity of the system. The system further includes an antenna array comprised of a plurality of elements that are spaced to reduce ambiguities in the subsequently determined N values. In one embodiment, several pair of elements are used. The spacing between the elements comprise the pairs and the spacing between pairs reduces ambiguities. The antenna system also includes a beamformer for producing a plurality of beams and a device for using the plurality of beams to determine N values associated with the object. The amplitude of the plurality of beams can be compared to obtain coarse data on the object.

Abstract: The present invention provides an improved antenna system that, in one embodiment, includes an antenna array comprised of a plurality of elements, each of which is capable of providing a signal. Also included in the improved antenna system is a multi-beam beamformer for producing two spatially independent overlapping beams from the signals provided by two different subsets of the antenna array. The phase of the two beams is compared to realize an interferometer that can provide high or fine resolution data on the position of an object relative to the antenna system. The amplitude of the two beams can also be compared to obtain coarse data on the position of the object. The beamformer includes a switching network for selecting which elements of the antenna array form the two subsets. This permits, for example, the position of the beams to moved, the baseline of the two beams to be varied, and/or the beam width of the beams to be altered.

Abstract: An antenna apparatus capable of generating scanning beams through a range of 0°-90° is provided. The antenna apparatus includes one or more rows of antenna elements, with the antenna elements in each row being arranged in pairs. The elements within a pair are separated by a distance of about lambda/four, and the pairs are separated by a distance of about lambda/two, where lambda is the wavelength of the center frequency of signals transmitted from the antenna apparatus. Transmit/receive circuitry may be electrically connected to each pair of antenna elements, with the signal to elements within a pair having a phase quadrature relationship so that the pair of antenna elements generates a scanning beam in one direction and a control pattern null is achieved in another direction. A control system controls the generation of a scanning beam output by the antenna apparatus.

Abstract: A cross-link antenna system including a plurality of spacecraft in a constellation is provided. Each of the spacecraft includes an antenna. One or more of the antennas has a number of antenna elements that can be controllably energized. Determined or selected phases and amplitudes can be individually applied through phase shifters and amplifiers to the antenna elements. In determining phase values for energizing the antenna elements to provide the receive beam in the direction of the current transmit antenna of one of the spacecraft in the constellation, location information is obtained for the transmit spacecraft and each of the beam receiving spacecraft. Additionally, attitude information for each receive spacecraft is found and location information associated with each of the antenna elements for each receive antenna is obtained.

Abstract: A radio frequency reconfigurable lens is provided. In particular, a lens comprising at least two opposed frequency selective surface sheets is provided. A relative phase shift may be imparted to an incident radio frequency wave by varying the distance between at least some of the unit cells of a first of the FSS sheets and adjacent unit cells on a second of the FSS sheets. In order to provide a desired phase taper across the width of a lens, and/or to provide different phase shift amounts, pairs of FSS surfaces having controllable columns or rows can be cascaded together. According to an additional aspect of the present invention, radio frequency waves can be scanned by cascading multiple tunable stages. The present invention also provides a radio frequency shutter.

Abstract: Method and apparatus for providing a configurable circuit are disclosed. In addition, method and apparatus for providing a phased array antenna having an integrated configurable circuit are provided. According to the present invention, at least a first component of a configurable circuit is formed on a first substrate. At least a second component of a configurable circuit is formed on at least a portion of a moveable cantilever formed from a second substrate. The first and second substrates are registered with one another to form a completed configurable circuit. According to the present invention, a configurable circuit may comprise a variable capacitor or a switch. In addition, a configurable circuit may be used in connection with phase shifting a radio frequency signal provided to an element of a phased array antenna.