Hughes Aircraft Company

Hrl Laboratories, LLC

Adrian E Popa

William B Bridges

Irwin L Newberg

James H Schaffner

Jan Grinberg

Emanuel Marom

Thomas R O'Meara

Robert R Hayes

Bernard H Soffer

Harry T Wang

Michael Wechsberg

John K Keigharn

Bill H Otoide

An antenna. The antenna includes a first dielectric antenna rod having a first dielectric constant. The first dielectric antenna rod is coupled to a first frequency transmission source for propagating first frequency band radiation from the first dielectric antenna rod into a medium having a medium dielectric constant. A second dielectric antenna rod is provided having a second dielectric constant. The second dielectric antenna rod is coupled to a second frequency transmission source for propagating second frequency band radiation from the second dielectric antenna rod into the medium. The first dielectric antenna rod is coaxially mounted within the second dielectric antenna rod. The first dielectric constant is greater than the second dielectric constant. The second dielectric constant is greater than the medium dielectric constant.

Coaxial dielectric rod antenna with multi-frequency collinear apertures

A programmable fiber optic delay system employs multiple programmable fiber optic delay lines, and switches among the delay lines for inclusion in an overall delay path. Switching among the delay lines is coordinated with the programming of those lines so that only a delay line with a settled delay program is included in the overall delay path. Each delay line consists of a plurality of fiber optic segments of varying length. The line's delay is programmed by switching in particular segments whose aggregate lengths correspond to a desired delay period. The multiple delay lines are used to simulate target speed and distance for use in testing a radar system. The programming of each individual delay line and the switching between lines is preferably controlled by a computer resident in the target simulator.

Programmable fiber optic delay line, and radar target simulation system

An electro-optic modulator (10) includes a pair of optical waveguide channels (20, 22) formed in an X-cut lithium niobate substrate (12) and an overlying RF coplanar waveguide (36). A periodic electrode structure (48) of the intermittent interaction type employs a plurality of middle stubs (52) to maintain the phase of the RF drive frequency in phase with the optical signal. The modulator (10) also utilizes shorter stubs (64) and tapered inlets (42) and outlets (44) to match and transform impedances.

Electro-optic modulator

A radar test set target which is co-located with the radar and produces a faithful replica of the radar signal substantially delayed in time. The radar signal modulates a laser light which is controllable delayed in time by transmitting the modulated laser light through a fiber optic delay line. The output of the delay line is demodulated and the extracted and delayed radar signal is returned to the radar as a test signal.

Delayed replica radar test set target

A high frequency spectral analysis system and method operates by modulating an optical beam with a high frequency signal to be analyzed, and sampling the beam simultaneously at periodically spaced locations along its length. The sampled portions are then focused to a spectral mapping. In the preferred embodiment a beam is directed in a zigzag pattern through a plate, one surface of which is totally reflective and the opposite surface of which is partially reflective. Periodic parallel samples are obtained from the minor portions of the beam which are transmitted out of the plate through the partially reflective surface. The totally reflective surface is preferably formed as a series of cylindrical surfaces which focus the beam to small spots at the partially reflective surface, thereby permitting a higher spatial density of samples without overlapping. The plate thickness is selected so that the beam is sampled at the Nyquist rate for the highest frequency contained in the signal of interest.

Method and apparatus for ultra high frequency spectrum analysis

In a radar having electrical transmitting and receiving circuitry, and an antenna for the radiation of microwave signals, there is provided an optical feed system which couples the antenna with the transmitting and receiving circuitry. The feed system includes a set of optical multiplexers interconnected by sets of optical fibers. Microwave energy of the radar is converted to optical radiation for communication to the antenna, and then converted back to the microwave energy. Electro-optic modulators and photoelectric detectors provide for the energy conversion. A plurality of signals, including both signals having the transmit waveform as well as control signals, can be simultaneously coupled via the optical fibers by utilization of radiation of differing frequencies. The multiplexers include dichroic mirrors for separation of the radiations of the differing frequencies. The fiber optic feed system retains the full beam steering capacity of the radar and permits the use of conventional electronic circuitry with the feed network of the optical feed system.

Fiber optic feed network for radar

A dielectric waveguide is disposed adjacent to a diode array which allows for coupling of energy therebetween. The waveguide has a core section and a cladding section encompassing a core section except in a portion thereof. The diode array is disposed adjacent to the exposed core portion at a proximity which allows evanescent coupling of energy between energy traversing the waveguide and the diodes of the diode array. A variety of microwave devices may be provided by this arrangement which include a signal source, detector, harmonic generator, upconverter, down-converter, or power combiner, depending upon the types of signals and manner of application of the signals applied to the waveguide and to the diode array.

Evanescent-wave coupling device

Millimeter wave transmission lines are disclosed for propagating electromagnetic waves of a wavelength ranging from about 10 mm to about 0.4 mm. The transmission lines comprise a fiber of co-crystallized thallium bromo-iodide consisting of from about 40 mole percent to about 46 mole percent thallium bromide and from about 60 mole percent to about 54 mole percent thallium iodide. The fiber may be cladded with a dielectric material having a dielectric constant less than that of the fiber. A number of alternate fiber and cladding cross-sectional configurations are disclosed including circular, square, rectangular, and elliptical.

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Thousand Oaks, CA, United States of America

Adrian E Popa