A dual-band antenna is provided that combines two normally disparate communications modes into a single compact aperture minimizing overall mass and volume, while maintaining high performance efficiency and reciprocity of each individual mode. The antenna is compatible with both optical (near-IR/visible) and RF (microwave/millimeter-wave) transceiver subsystems for high bandwidth communications, applicable primarily to long- to extremely long-range (space-to-ground) link distances. The optical link provides high bandwidth while the RF provides a lower data-rate weather backup, accommodation for traditional navigation techniques, and assistance in cueing the extremely tight optical beam by matching the RF beamwidth to an optical fine-steering mechanism field-of-regard. The configuration is built around a near-diffraction-limited high performance primary mirror shared by both a direct-fed RF antenna design and a Cassegrain optical telescope. Material properties are exploited to combine the optical secondary mirror with the RF feed structure, providing a collimated optical beam interface at the antenna vertex.

Dual band radio frequency (RF) and optical communications antenna and terminal design methodology and implementation

A gaze-point detection system includes at least one infrared (IR) signal source to be placed in a test scene as a reference point, a pair of eye glasses to be worn by a person, and a data processing and storage unit for calculating a gaze point of the person wearing the pair of eye glasses. The pair of eye glasses includes an image sensor, an eye-tracking unit and a camera. The image sensor detects IR signals from the at least one IR signal source and generates an IR signal source tracking signal. The eye-tracking unit determines adapted to determine the gaze direction of the person and generates an eye-tracking signal, and the camera acquires a test scene picture. The data processing and storage unit communicates with the pair of eye glasses and calculates the gaze point relative to the test scene picture.

Detection of gaze point assisted by optical reference signal

A standoff range, sense-through-obstruction radar system is capable of detecting micro-Doppler, or life form signatures, and movements through obstructions at stand-off ranges and displaying the target information over a live video feed of the area under surveillance. The sense-through-obstruction radar system comprises an antenna assembly that includes a horn antenna and a reflector configured to reflect radio frequency (RF) energy to/from the horn antenna. An antenna pointing assembly supports the antenna assembly. The antenna pointing assembly is configured to move the antenna assembly to point the antenna assembly toward an obstruction. A sensor assembly is mounted to the antenna assembly so that the sensor assembly is aligned with the RF beam formed from the RF energy reflected from the reflector to the horn antenna. The sensor assembly is configured to detect the location of the obstruction and to provide information to assist pointing of the antenna assembly toward the obstruction.

Standoff range sense through obstruction radar system

An assembly is provided that may be used in high data rate optical communications, such as free-space communication systems. The assembly may include a main optical receiver element and a lenslet array or other optical element disposed near the focal plane that collects an optical signal and focuses that signal as a series of optical signal portions onto a photodetector array, formed of a series of InGaAs photodiodes, for example. The electrical signals from the photodetectors may be amplified using high bandwidth transimpedance amplifiers connected to a summing amplifier or circuit that produces a summed electrical signal. Alternatively, the electrical signals may be summed initially and then amplified via a transimpedance amplifier. The assembly may be used in remote optical communication systems, including free-space laser communication environments, to convert optical signals up to or above 1 Gbit/s or higher data rates into electrical signals at 1 Gbit/s or higher data rates.

Lenslet/detector array assembly for high data rate optical communications

Embodiments of methods, devices and systems are presented for communicating information in an explosive environment. An explosion proof video and data communication module includes features that prevent the generation of a spark or other ignition sources that could ignite explosive dust, gas or vapors in the air. The explosion proof video and communications relay modules may operate independently or as a group to provide real-time information, situation awareness, functionally and responsiveness for personnel that are in explosive environments.

Method and system for providing explosion proof video and communication relay module

A reflector antenna arrangement can transmit and receive both infrared (IR) and millimeter wave (RF) radiation. The arrangement includes a main reflector ( 1 ), a subreflector ( 2 ), an IR feed system ( 4 ), an RF feed system ( 3 ), a radome ( 5 ), and a bispectral window ( 6 ) arranged in an opening provided in a central area of the main reflector ( 1 ). The RF feed system is oriented so that the RF radiation path includes a double reflection from the subreflector and from the main reflector, while the IR feed system is arranged directly behind the bispectral window so that the IR beam path extends directly through the bispectral window without reflecting from the main reflector or the subreflector. The bispectral window has a high reflectance for the RF radiation and a high transmittance of the IR radiation. The bispectral window is made of a dielectric material and has rotationally symmetrical front and back surfaces, whereby the front surface contour is optimally matched to the front surface of the main reflector and the back surface contour achieves an optimal reflectivity of the RF radiation and an optimal transmissivity of the IR radiation. Undesired influences between the IR radiation and the RF radiation are avoided by the separation of the signal beam paths.

RF and IR bispectral window and reflector antenna arrangement including the same

The bi spectral window is made of dielectric material with a low loss factor and high dielectric constant. The window has rotation symmetrical, aspherical front and rear surfaces. The front surface is arranged on the side of the reflector on which the millimeter wave radiation is incident, and is optimally matched to the reflector surface. The rear surface is designed for optimal millimeter wave reflectivity. An Independent claim is also included for a reflector antenna.

Dual-frequency window for a reflector and reflector antenna equipped with said window

Es wird ein bispektrales Fenster fur einen Reflektor fur den Infrarot- und Millimeterwellen-Bereich aus dieelektrischem Material mit rotationssymmetrischen Vorder- und Hinterflachen offenbart, wobei die Vorderflache optimal an die Reflektoroberflache angepast ist und die Hinterflache in Bezug auf optimale Millimeterwellen-Reflektivitat sowie optimale Infrarot-Transmittivitat ausgelegt ist. There is disclosed a bispectral window for a reflector for infrared and millimeter wave range from dieelektrischem material with rotationally symmetrical front and rear surfaces, the front surface is optimally adapted to the reflector surface and the rear surface with respect to optimal millimeter-wave reflectivity as well as optimum infrared is designed transmissivity. Dieses bispektrale Fenster wird gemas einem Ausfuhrungsbeispiel in einer Offset-GREGORY-Doppelreflektorantenne verwendet. This bispectral window is used according to an embodiment in an offset GREGORY double reflector antenna. Durch die Verwendung des bispektralen Fensters wird eine platzsparende Integration von Millimeterwellen- und Infrarotsystemen in einer Antenne ermoglicht, in der zudem eine unerwunschte Beeintrachtigung der Infrarot-Strahlung ausgeschlossen ist, da eine Trennung der Signalwege erfolgt. By using the bispectral window, a space-saving integration of millimeter wave and infrared systems in an antenna is made possible in an undesired interference of the infrared radiation is excluded as a separation of signaling pathways occurs.

Bispektrales Fenster für einen Reflektor und Reflektorantenne mit diesem bispektralen Fenster Bispectral window for a reflector and reflector antenna with this bispectral window

Near-field large-aperture antenna patterns at 94 GHz are probed using resonant, fiber-coupled photoconductive antennas triggered by a phase-locked fs-laser system A signal-to-noise ratio of 40 dB and a phase accuracy of 3 degrees are obtained

Gerhard Schindler

Papers

RF and IR bispectral window and reflector antenna arrangement including the same

Dual-frequency window for a reflector and reflector antenna equipped with said window

Bispektrales Fenster für einen Reflektor und Reflektorantenne mit diesem bispektralen Fenster Bispectral window for a reflector and reflector antenna with this bispectral window

94 GHz radar antenna characterization with synchronized near-field photoconductive sampling

Bispectral window for a reflector and reflector antenna with this bispectral window