Raytheon Company

Hughes Aircraft Company

Hughes Electronics Corporation

Ralston S Robertson

William Henderson

Robert T Lewis

Harry B Marr

Romulo J Broas

David W Baker

Robert A Rosen

Kapriel V Krikorian

Brian M Pierce

Daniel G Thompson

Pyong K Park

Garry N Hulderman

Robert L Eisenhart

Joel Blumke

Louis A Kurtz

Thomas A Kennedy

Ruey-Shi Chu

Ronak D Shah

John N Poelker

Eric L Holzman

Joel C Blumke

David R Ulmer

Chester Lo

William T Henderson

A system for beamforming, in a phased array antenna. Subtraction of a sinusoidal signal from a received signal, or from a signal to be transmitted, is used to shift the phase of the received signal, or from a signal to be transmitted. A separate sinusoidal signal may be generated for each antenna array element, making it possible to shift the phase on a per-element basis, to perform beamforming.

Direct digital synthesis based phase shift digital beam forming

A system for converting a digital signal to an analog signal, the digital signal having a center frequency, includes: a multi-Nyquist DAC; a clock; and a controller configured to: control the clock to generate a clock signal such that the center frequency of the digital signal is an integer multiple of half the frequency of the clock signal, the clock being configured to supply the clock signal to the multi-Nyquist DAC and to the controller; and supply the digital signal to the multi-Nyquist DAC to generate an output signal.

Digital clock update methodology for multi-Nyquist constructive interference to boost signal power in radio frequency transmission

A phase shifter operable at microwave or millimeter-wave frequencies includes a dielectric substrate with a bottom surface having a conductive ground plane layer and a conductive patterned layer formed on a top surface to define a conductor pattern. A series of active tuning elements is mounted on the top surface and cascaded along a propagation direction in a spaced arrangement along a longitudinal extent. A housing structure includes a bottom housing structure with a planar conductive bottom surface for contacting the ground plane layer, and a top housing structure fabricated with a channel which extend along the longitudinal extent and provide clearance for the active tuning elements. A bias circuit is connected to the respective series of active tuning elements.

Transverse device phase shifter

Provided is a non-federated multi-function exciter. The non-federated multi-function exciter includes a waveform generator subsystem operable to provide waveforms programmable in time, duration, slope and frequency. A transmission subsystem is coupled to the waveform generator, the transmission subsystem having a first upconverter and a second upconverter coupled to the first upconverter. A communication modulation subsystem is coupled to the second upconverter of the transmission subsystem. A reference clock subsystem coupled to the waveform generator subsystem, the transmit subsystem and the communication modulation subsystem. The non-federated multi-function exciter is operable to generate interleaved radar and communication signals.

Non-federated multi-function Ka-band exciter system and method

An antenna array employing continuous transverse stubs as radiating elements is described, which includes an upper conductive plate structure comprising a set of continuous transverse stubs, and a lower conductive plate structure disposed in a spaced relationship relative to the upper plate structure. The upper plate structure and the lower plate structure define an overmoded waveguide medium for propagation of electromagnetic energy. For each of the stubs, one or more transverse device array phase shifters are disposed therein.

Transverse device array radiator ESA

A transverse device array phase shifter includes an overmoded waveguide structure having a top conductive broad wall surface, a bottom conductive broad wall surface and opposed first and second conductive side wall surfaces. At least one transverse device array circuit is positioned in the waveguide circuit. Each circuit comprises a generally planar dielectric substrate having a microwave circuit defined thereon, and a plurality of spaced discrete phase shifter elements. The substrate is disposed within the waveguide structure generally transverse to the side wall surfaces. A bias circuit applies a voltage to reverse bias the phase shifter elements. The transverse device array phase shifter circuit causes a change in phase of microwave or millimeter-wave energy propagating through the waveguide structure. An electronically scanned antenna array employing continuous transverse stubs as radiating elements, with an upper conductive plate structure comprising a set of continuous transverse stubs, and a lower conductive plate structure disposed in a spaced relationship relative to the upper plate structure. At least one transverse device array phase shifter circuit is disposed between selected adjacent pairs of stubs. An electronically tunable antenna array employing continuous transverse stubs as radiating elements and transverse diode array phase shifters, which includes a short circuit termination disposed between the upper conductive plate and the lower conductive plate. At least one transverse device array phase shifter circuit is positioned between the short circuit termination and an adjacent stub to provide tuning.

Transverse device array phase shifter circuit techniques and antennas

A dielectric covered continuous slot (DCCS) antenna operable at RF frequencies. The antenna includes a conical or cylindrical dielectric radome structure having a nominal thickness equal to one quarter wavelength at a frequency of operation of the antenna. A conductive layer is defined on a contour surface of the radome structure, with a plurality of continuous slots defined in the conductive layer. The slots extend circumferentially about the longitudinal axis of the antenna and are spaced apart in a longitudinal sense. A serpentine end-fed signal transmission structure is disposed within the radome structure for carrying RF feed signals from an excitation end of the structure to a second end of the transmission structure. The slots are disposed along the serpentine transmission structure such that energy leaks from the transmission structure through the slots and the radome structure, forming a beam which is scannable in a direction along the longitudinal antenna axis by scanning the transmit signal frequency. Due to the frequency dispersive effective electrical length of the transmission structure, the slot spacing effectively changes as the frequency is scanned, thereby scanning the beam. The antenna provides room for an IR (infrared) seeker in the nose of the cone, without blocking the view of the conical/cylindrical antenna.

Electronically scanned dielectric covered continuous slot antenna conformal to the cone for dual mode seeker

An electronically scanned antenna that is manufactured using semiconductor material and device fabrication technology. The antenna has a semiconductor substrate having a plurality of stubs projecting from one surface. The semiconductor substrate may be silicon, gallium arsenide, or indium phosphide, for example. A first conductive layer formed on the surfaces of the semiconductor substrate and along sides of the stubs so that the stubs are open at their terminus. The conductive layers form a parallel plate waveguide region. A diode array having a plurality of diode elements is formed in the semiconductor substrate that are disposed transversely across the semiconductor substrate and longitudinally down the semiconductor substrate between selected ones of the plurality of stubs. The diode array may comprise an array of Schottky or varactor diodes, for example. The diode array provides a voltage variable capacitive reactance and hence a phase shift to the electromagnetic energy propagating in selective regions of the waveguide region. This results in a scanning of the antenna beam radiated from the studs. A beam steering computer is coupled to the plurality of diode elements of the diode array which controls the voltage applied thereto to control steering of a beam radiated by the antenna.

Electronically scanned semiconductor antenna

Methods that compensate for phase errors caused by path length variations in a radar system, and that compensate for relative phase errors in upconvertor and downconverter references employed in the radar system. One method samples a signal reflected from a duplexer through a receiver during the time the radar pulse is transmitted. The signal reflected from the duplexer is compared to a radar echo pulse on a single pulse basis. The phase of the sampled signal is subtracted from the phase of the received radar echo pulse reflected to determine the phase error. In a second method, multiple samples are collected during the time each radar pulse is transmitted. Samples of the signal reflected from the duplexer and the radar echo pulse are compared on a pulse to pulse basis. The phase differences are averaged across the pulse duration. The averaged phase differences are integrated on a pulse to pulse basis to determine the phase error.

Compensation for radar path length variation and phase error

A polarimetric antenna (20) comprises a length of circular waveguide (30) having a sidewall (32) with a cylindrical internal surface (34). The sidewall (32) has two longitudinal slots (38) that extend parallel to a longitudinal axis (36) of the waveguide (30) and are symmetrically positioned with respect to the circumference of the circular waveguide (30). A first rectangular waveguide (40) communicates with one of the longitudinal slots (38), and a second rectangular waveguide (42) communicates with the other longitudinal slot (38), but is short circuited by a closure (44) at one end thereof. A transverse closure (46) is positioned over the circular waveguide (30) at one end, the closure (46) having a first and a second transverse slot (48, 50) therein. These slots (48, 50), which are preferably arcuate in form, are positioned symmetrically with respect to a longitudinal axis (36) of the circular waveguide (30). A third rectangular waveguide (52) is in communication with the first transverse slot (48), and a fourth rectangular waveguide (54) is in communication with the second transverse slot (50). The two rectangular waveguides (52, 54) are preferably excited through an E-plane folded magic Tee (58). This antenna (20) is used to radiate sub-microwave, microwave, or millimeter wave energy in applications such as a cassegrain tracking antenna (22).

Polarimetric antenna

A voltage controlled oscillator having improved frequency linearization characteristics. A radial line, (top-hat) disc geometry in conjunction with a varactor diode are disposed in a broadband, ridged waveguide oscillator circuit to produce a frequency linearized voltage controlled oscillator. A negative resistance device is recessed into the ridged waveguide and coaxially coupled via an impedance transformer to the ridged waveguide cavity. The present invention uses a disc resonator in a ridged waveguide to transform the microwave impedance of a non-RF generating element, a varactor diode, to values which provide improved voltage controlled oscillator tuning linearity. The disc resonator or radial line is located above the varactor diode. The radial line transforms the microave impedance of the varactor diode to a new value which is then coupled into the ridged waveguide circuit and subsequently to the RF generating diode. The circuit impedance, which is a function of the varactor voltage, acts to linearize the frequency versus voltage characteristic of the diode. A comparison of the operation of the circuit with and without the radial line/tuning disc shows a 13:1 improvement in the frequency linearity. Experimental results show that the circuit configuration of the present invention is ideal for use in microwave and millimeter-wave voltage conrolled oscillators which require inherent frequency versus voltage linearity. Since the voltage controlled oscillator frequency linearity is a critical factor in phase locked loop performance, it is especially suited for use in microwave and millimeter-wave radar or communication systems which are frequency agile.

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Northridge, CA, United States of America

Ralston S Robertson