Abstract: A system (10) for rotating a polarization state of a beam of electromagnetic energy (22) of the present invention. The system (10) includes a first mechanism (16) for receiving the beam of electromagnetic energy (22). The beam of electromagnetic energy (22) is characterized by a first arbitrary polarization state oriented at a first angle. A second mechanism (16, 18, 20) orients the first arbitrary polarization state, via one or more waveplates (16, 18, 20), at a second angle that is different from the first angle. In a specific embodiment, the one or more waveplates (16, 18, 20) include a first quarter waveplate (16) having a principal axis (26) angled at 45° from horizontal relative to a given reference frame. A second quarter waveplate (20) is angled at −45°.

Abstract: A grid array interconnect structure and method for interconnecting and removing a high density multichip interconnect decal, or grid array package, to and from a printed wiring board. The interconnect structure comprises conductive epoxy interconnects and nonconductive transfer tape that has adhesive disposed on both sides thereof. The transfer tape is applied to the back of the high density multichip interconnect decal or package. Conductive epoxy is disposed in pre-formed holes of the two-sided transfer tape and is partially cured to a semi-rigid condition to form the conductive epoxy interconnects. A mylar film may be applied to the exposed surface of the transfer tape. With the mylar film removed from the surface of the transfer tape, the decal or package is secured to the printed wiring board and a slight force is applied. This assembly is then cured.

Abstract: Methods of fabricating air-filed true-time-delay, continuous transverse stub array antenna. A plurality of extruded sections that are physically independent of one another are fabricated. The plurality of extruded sections are arranged in a predefined pattern defining the structure of the array antenna. Adjacent surfaces of the extruded sections form waveguides of the array antenna. The plurality of extruded sections are joined together at their respective ends to form the array antenna. The plurality of extruded sections may be joined using a plurality of end plates. The plurality of extruded sections and end plates may comprise metal or plastic. If the extruded sections are plastic, they are metallized 44 using a process such as vacuum deposition, electroless plating, or lamination during the extrusion process. The end plates are sealed to the extruded sections to form the array antenna structure.

Abstract: An electronic warfare system for detecting missiles which appear as points in an IR image. The system includes a point detect filter with two stages. The first stage produces a characteristic rabbit ear pattern in response to a pulse. The second stage produces a pulse in response to the rabbit ear pattern.

Abstract: A space-fed active array lens antenna system has an active array lens with a first array of radiating elements defining a front antenna aperture which transmits and receives RF energy from free space, a second array of radiating elements defining a rear antenna aperture which transmits and receives RF energy from a feed aperture, and an array of transmit/receive (T/R) modules sandwiched between the front aperture and rear aperture. The T/R modules include a phase control circuit and an amplitude control circuit which provide phase and amplitude control for RF signals passing through the modules. The feed aperture includes a wide band CTS aperture which produces a plane wave in the near field.

Abstract: A sensor/support system includes a sensor assembly having a planar radiation detector lying parallel to a reference plane, a readout circuit, and an interconnect joining the radiation detector to the readout circuit. The system further includes a support structure, the support structure having a platform with a first side to which the sensor assembly is affixed and a second side oppositely disposed from the first side. A shim is affixed to the second side of the platform. The shim is made of a shim material different from the detector material and the platform material. The shim reduces the strain in the interconnect when the temperature of the sensor/support system is changed, as compared with the strain in the interconnect in the absence of the stabilization structure.

Abstract: An optically-pumped laser having a gain medium configured to provide a low loss, three-dimensional integrated optical pump cavity that substantially confines optical pump radiation within the lasing volume, which is particularly useful for efficiently pumping solid state gain media that has low pump dopant concentration. The integrated pump cavity includes a plurality of boundaries contiguous with the gain medium. An optical pump source such as a laser diode array supplies optical pump radiation that is input into the gain medium through one or more pump cavity windows with a propagation direction transverse to a laser axis defined through the gain medium. In some embodiments, an optical surface is situated opposite the window to approximately recollimate the input pump radiation. The optical pump cavity may be designed to concentrate the optical pump radiation and approximately uniformly pump the entire volume of the lasing medium.

Abstract: An RF interconnect is incorporated in RF module packages for direct attachment onto a multi-layer PWB using compressible center conductor (fuzz button) interconnects. The module has circuitry operating at microwave frequencies. The module package includes a metal housing including a metal bottom wall structure. The module includes a plurality of RF interconnects, which provide RF interconnection between the package and the PWB. Each interconnect includes a feedthrough center pin protruding through an opening formed in the metal bottom wall, with isolation provided by a dielectric feedthrough insulator. The center pin is surrounded with a ring of shield pins attached to the external surface of the bottom wall of the module housing. The pins are insertable in holes formed in the PWB, and make contact with fuzz button interconnects disposed in the holes. Circuitry connects the fuzz button interconnects to appropriate levels of the PWB for grounding and RF signal conduction.

Abstract: A multi-channel microwave switched filter bank, wherein the input circuitry and output circuitry are mounted on opposite sides of the filter bank, providing a compact structure with excellent isolation. The filter bank includes a set of microwave band pass filter circuits. A housing structure provides an outer conductive peripheral frame structure. A rack structure disposed within the housing structure has a plurality of elongated slots for mounting therein corresponding ones of the plurality of filter circuits. A top dielectric substrate board is mounted adjacent a first side of the rack structure and has a first set of openings formed therein for providing access to a first set of input/output (I/O) ports of the plurality of filter circuits. A bottom dielectric substrate board is mounted adjacent a second side of the rack structure opposite the first side and has a second set of openings formed therein for providing access to a second set of input/output (I/O) ports of the plurality of filter circuits.

Abstract: An optical system has an outer dome and a detector system with an optical train and a sensor disposed to receive an optical ray passing sequentially through the outer dome and the optical train. The optical train includes a solid catadioptric imaging lens which is symmetric about a lens axis. The solid catadioptric imaging lens has a bore therethrough coincident with the lens axis, to prevent stray light from reaching the sensor. The bore is desirably filled with an opaque material or has a ground glass wall.

Abstract: A glue-gun applied hot-melt radar-absorbing material (RAM) and method of use thereof is provided. The hot-melt radar-absorbing material composition comprises: (a) 70 to 85 wt % carbonyl iron powder; (b) 2 to 10 wt % of a metal deactivator; and (c) balance a thermoplastic polyurethane. The method for repair of a body comprising a radar-absorbing material, comprises: (a) formulating the hot-melt radar-absorbing material of the present invention; (b) forming the hot-melt radar-absorbing material into a shape; (c) applying the hot-melt radar-absorbing material in a molten state onto the body; and (d) allowing the hot-melt radar-absorbing material to cool to room temperature. The shape of the hot-melt RAM is advantageously a “glue stick”, which is configured to go into a glue gun. The repair operator loads the glue stick into the glue gun and pulls the trigger. The glue gun heats the glue stick, and the molten material is applied to the area to be repaired.

Abstract: A two-color infrared warning device, having both wide-angle and narrow-angle search capabilities, and a directional countermeasure device are mounted on a gimbal pointing in the same direction. The warning device and gimbal are initially operated in a wide-angle, step-stare mode to search for threats. When a potential hostile target is found, the warning device changes to a narrow-angle mode to determine whether the potential target is hostile. When a hostile target is identified, the directional countermeasure device, which is pointed at the target by virtue of its mounting with the warning device on the gimbal, is activated.

Abstract: A compact four-way waveguide power divider (10). The inventive power divider (10) includes an input waveguide (11) that terminates at a junction with two adjacent waveguides on opposite sides of the input waveguide. On the opposite side of the junction is a conducting wall into which is built an inductive septum (20). The inductive septum (20) serves to partially match the input impedance of the structure. Second and third inductive septums (22 and 24) are also built into the output arms of the power divider (10). The purpose of the second and third septums (22 and 24) is twofold. In addition to partially matching the power divider's input impedance, the positions of the second and third septums (22 and 24) can be adjusted to equalize the power division between the output arms. Hence, the waves exiting the four output arms of the power divider have highly equalized amplitudes and phases. Further, the phases at the output ports are equalized by adjusting the lengths of the output arms.

Abstract: An equalization system and method. In a most general sense, the inventive equalization system includes first and second filters for filtering an in-phase component of a received signal in accordance with first and second sets of coefficients, respectively. The system includes third and fourth filters for filtering a quadrature component of the input signal in accordance with third and fourth sets of coefficients, respectively. The outputs of the first and third filters are subtracted to provide an equalized in-phase output signal and the outputs of the second and fourth filters are added to provide an equalized quadrature output signal. In the illustrative embodiment the filters are finite impulse response filters and the coefficients are provided by a microprocessor. In accordance with the present teachings, the filters are implemented in a general purpose filter. The delay elements of the filters are calculated in accordance with a mean square error algorithm.

Abstract: A passively operated thermal diode for controlling heat transfer from heat-generating electronic components to an external environment through an airframe is provided. The thermal diode comprises: (a) an electronics package within the airframe; (b) a heat-transferring mechanism thermally connected to the electronics package and controllably disengagable from thermal contact with the airframe at a predetermined temperature; (c) a shape-memory alloy component having a phase change at the predetermined temperature for thermally disconnecting the electronics package from the airframe once the predetermined temperature is exceeded; and (d) a spring for maintaining the heat-transferring mechanism in thermal contact the airframe below the predetermined temperature. The present invention solves the problem of heat transfer by introducing a shape-memory-alloy sensor-actuator component.

Abstract: A centrally-obscured reflective telescope having a semi-active focus and thermal compensation system. The telescope has a housing having an input window, a primary mirror, a secondary mirror suspended between the input window and the primary mirror by support struts, an optional tertiary mirror, and an optional fold mirror. The system includes one or more heating elements respectively disposed on each of the support struts. A first temperature sensor (disposed on the primary mirror) generates a reference temperature, a second temperature sensor is disposed on the secondary mirror, and one or more third temperature sensors are disposed on each of the support struts. A temperature compensation controller is coupled to the heating elements and temperature sensors and controls the heat output of the plurality of heating elements to heat the support struts and control the position of the secondary mirror relative to the primary mirror.

Abstract: The system (10) includes a first mechanism (12) for receiving electromagnetic energy of a first wavelength from the scene (28) and providing electromagnetic energy of a second wavelength shorter than the first wavelength. A second mechanism (14) measures variations of the electromagnetic energy of the second wavelength over a predetermined area. The system is a millimeter wave imaging system (10). The first mechanism (12) includes a lens (12) having an index of refraction substantially greater than 1. The lens (12) is opaque to infrared electromagnetic energy and made of alumina, plastic, or other material having a relatively high index of refraction. The second mechanism (24) includes and array of bolometers (24) positioned parallel to an output aperture (24) of the lens and within a distance of the output aperture (24) that is much smaller than the second wavelength.

Abstract: A low cost array with wide band elements interleaved into an “egg-crate” structure. The radiating elements are flared notch radiators. Good impedance match over a wide band was achieved by feeding each element with a tapered quasi-TEM slot line, which transforms a 50-ohm input impedance to a 120-ohm radiation impedance. The radiating elements are fed by a true time delay beam-forming network to ensure that the main beam points.

Abstract: A low noise, low distortion radio frequency amplifier which includes a bootstrap design to minimize intermodulation distortion while simultaneously achieving low noise and wide bandwidth. In the illustrative embodiment, the invention includes a first circuit for receiving an input signal; a second circuit for amplifying the input signal using a transistor Q2; and a third circuit for regulating a rate of change of voltage across the transistor Q2 such that the rate of voltage change is zero. The third circuit includes a transistor Q3 connected to the transistor Q2 in cascode. In the specific illustrative embodiment, the third circuit further includes two diodes D1 and D2 used to modulate the voltage at the input of the transistor Q3 in proportion to the voltage modulation at the input of the transistor Q2. In the illustrative embodiment, the second circuit includes a transistor Q1 connected in cascade to the transistor Q2.

Abstract: An infrared-transparent structure includes a first infrared-transparent element that is transparent to infrared radiation in the 3.6-7 micrometer wavelength range, preferably coated with a zinc-sulfide antireflective coating, and a layer of a solvent-free, infrared-transparent polymer transparent on the first infrared-transparent element. The polymer is formed of an addition-cured silicone, such as addition-cured dimethyl silicone, and a small amount of an adhesion promoter, such as 3-glycidoxypropyltrimethoxysilane. The polymer layer may either be a surface layer, or it may be used as an adhesive between the first infrared-transparent element and a second infrared-transparent element.