Abstract: A system and a method for calibrating an output signal of an antenna is disclosed. In one aspect, an apparatus includes a first digital adder configured to generate a gain offset by at least adding gain calibration data from non-volatile memory and gain command data from static memory. The apparatus further includes an amplitude gain circuit configured to modify, based at least in part on the gain offset, an amplitude of a first output signal of a first antenna. The modified amplitude of the first output signal is provided to enable pre-calibration of the first output signal. The apparatus further includes a power detector configured to measure an output power of the first output signal. The apparatus further includes at least one processor configured to generate a difference between the measured and expected output power, and adjust gain command data in response to the generated difference.

Abstract: A system and a method for calibrating an output signal of an antenna is disclosed. In one aspect, an apparatus includes a first digital adder configured to generate a gain offset by at least adding gain calibration data from non-volatile memory and gain command data from static memory. The apparatus further includes an amplitude gain circuit configured to modify, based at least in part on the gain offset, an amplitude of a first output signal of a first antenna. The modified amplitude of the first output signal is provided to enable pre-calibration of the first output signal. The apparatus further includes a power detector configured to measure an output power of the first output signal. The apparatus further includes at least one processor configured to generate a difference between the measured and expected output power, and adjust gain command data in response to the generated difference.

Abstract: In some example implementations, there may be provided methods for beamforming calibration of active electronically steered arrays (AESA). In some implementations, one or more adders may generate a phase offset by adding phase calibration data from non-volatile memory and phase command data from static memory, and/or generate a gain offset by adding gain calibration data from the non-volatile memory and gain command data from the static memory. Further, a phase-shift circuit can modify, based on the phase offset, a phase of a first output signal, and an amplitude gain circuit can modify, based on the gain offset, an amplitude of the first output signal. In accordance with these implementations, the modified phase of the first output signal and the modified amplitude of the first output signal are provided to enable pre-calibration of the first output signal and/or a first antenna. Related systems, methods, and articles of manufacture are also described.

Abstract: An apparatus may include a plurality of antenna elements forming an antenna array. The apparatus may further include a beamformer that determines one or more of phase and amplitude shifts to cause the plurality of antenna elements to produce a beam in the direction of a target. The apparatus may further include a null limiter comprising dither circuits. The dither circuits may dither the one or more of phase and amplitude shifts by adding noise to cause a side lobe of the beam to increase above a threshold value. The dither circuits may be enabled by a control signal, and the dithered one or more of phase and amplitude shifts may be provided to the antenna elements to produce the beam in the direction of the target with the side lobes above the threshold value.

Abstract: In some example implementations, there may be provided methods for beamforming calibration of active electronically steered arrays (AESA). In some implementations, one or more adders may generate a phase offset by adding phase calibration data from non-volatile memory and phase command data from static memory, and/or generate a gain offset by adding gain calibration data from the non-volatile memory and gain command data from the static memory. Further, a phase-shift circuit can modify, based on the phase offset, a phase of a first output signal, and an amplitude gain circuit can modify, based on the gain offset, an amplitude of the first output signal. In accordance with these implementations, the modified phase of the first output signal and the modified amplitude of the first output signal are provided to enable pre-calibration of the first output signal and/or a first antenna. Related systems, methods, and articles of manufacture are also described.

Abstract: In some example implementations, there may be provided methods for beamforming calibration of active electronically steered arrays (AESA). In some implementations, one or more adders may generate a phase offset by adding phase calibration data from non-volatile memory and phase command data from static memory, and/or generate a gain offset by adding gain calibration data from the non-volatile memory and gain command data from the static memory. Further, a phase-shift circuit can modify, based on the phase offset, a phase of a first output signal, and an amplitude gain circuit can modify, based on the gain offset, an amplitude of the first output signal. In accordance with these implementations, the modified phase of the first output signal and the modified amplitude of the first output signal are provided to enable pre-calibration of the first output signal and/or a first antenna. Related systems, methods, and articles of manufacture are also described.

Abstract: An apparatus may include a plurality of antenna elements forming an antenna array. The apparatus may further include a beamformer that determines one or more of phase and amplitude shifts to cause the plurality of antenna elements to produce a beam in the direction of a target. The apparatus may further include a null limiter comprising dither circuits. The dither circuits may dither the one or more of phase and amplitude shifts by adding noise to cause a side lobe of the beam to increase above a threshold value. The dither circuits may be enabled by a control signal, and the dithered one or more of phase and amplitude shifts may be provided to the antenna elements to produce the beam in the direction of the target with the side lobes above the threshold value.

Abstract: A system for switching radio frequency signals from an input side (5, FIG. 1 ) to an output side (6) can be used to combine multiple input signals to form a single output and to distribute a single input signal to form multiple outputs. Gain correction amplifiers (20, 25) are employed to adjust the overall gain of a particular column and row of the switch matrix which minimizes the effect of variations in the gain of the amplified switching elements (30) which perform the switching function. Resistive matching units (70, FIG. 2) provide coupling to and from the amplified switching elements (30) without substantially changing the characteristic impedance of the input and output paths.

Abstract: A planar array antenna for use with an earth-based subscriber unit generates receive or transmit communications beams through the use of digital beamforming networks (210, 211) which provide beam steering in a first dimension. In another dimension, the communications beams are synthesized by way of a waveguide structure (300, FIG. 3) which is repeated for each row of the antenna array. The waveguide outputs are weighted due to the positioning of coupling slots (350) or coupling probes (450) which transfer carrier signals to and from each waveguide. The slots or coupling probes from the waveguides are coupled to a group of barium strontium titanate (BST) (360, FIG. 3) or micro-electromechanical systems (MEMS) switch (460, FIG. 4) phase shift elements which are under the control of a control network (221, 222, FIG. 2). The resulting signals are radiated by the antenna elements of the planar antenna array (310, FIG. 3) to form a communications beam.

Abstract: A mechanical scanning and digital beamforming antenna (20, FIG. 2) uses a receive and transmit digital beamforming network (FIG. 3, 410, 320) to provide communications beam scanning in a first plane. In a second plane, a reflective surface (FIG. 2, 240) is used to focus and scan the communications beam. Through proper orientation of the reflective surface (240), a communications satellite (FIG. 1, 10) can be tracked by way of electronic scanning by way of the transmit or receive digital beamforming network (FIG. 3, 320, 410). Thus, the complexity of the digital beamforming network is reduced as is the wear on the mechanical components of the antenna. The mechanical scanning and digital beamforming antenna (20, FIG. 20) makes use of a second digital beamforming network (FIG. 3, 415, 325) and reflective surface (FIG. 3, 250) to ensure that two communications satellites can be simultaneously tracked.

Abstract: An antenna subsystem (120) which comprises an electronic scanning reflector antenna (400) is used for the formation of single and multiple beams. Reflecting surface (420) is covered with at least one dielectric layer (430) which is used to simultaneously and independently steer multiple beams. Electronic scanning reflector antenna (400) operates similar to a phased array antenna. ESRA (400) comprises a number of independent controllable reflecting surfaces (450) which are combined together in close proximity. Each one of the individual regions is covered by a dielectric layer, and the dielectric constant for each can be independently controlled. Electronic scanning reflector antennas (400, 600) are used in both space-based and terrestrial-based applications. Electronic scanning reflector antennas (400, 600) are used for both transmission and reception of electromagnetic signals.

Abstract: An K-band amplifier circuit (10) with two samplers (12, 18) coupled to detectors (22, 26) that detect an input and an output RF signal level. These two reference signals are provided to a differential gain control circuit (24) which is coupled to one or more variable gain amplifier (VGA) (14) stages. The VGAs compensate for the gain of an entire chain of amplifiers (16). When the individual amplifier gains vary for any reason, (i.e., process, temperature effects or end of life degradation) the variation in gain causes higher or lower levels of detected output reference signals for a given RF input signal. The gain control circuit (24) drives the VGA (14) up or down as appropriate. By maintaining a constant offset in input and output reference control signals, the gain control circuit (24) drives the amplifier chain (16) to a constant gain.

Abstract: A user terminal (110) which comprises an electrically-controllable back-fed antenna (300, FIG. 3) is used for the formation of single and multiple beams. The electrically-controllable back-fed antenna comprises an RF power distribution/combination network (310), electrically-controllable phase-shifting elements (320), a control network (440, FIG. 4) and radiating/receiving elements (360). The control network is coupled to the electrically-controllable phase-shifting elements and is used for controlling the dielectric constant of dielectric material contained within the electrically-controllable phase-shifting elements. In a preferred embodiment, phase-shifting elements comprise waveguide sections containing at least one dielectric material, and the dielectric material includes a ferroelectric material, preferably comprising Barium Strontium Titanate (BST).

Abstract: Cellular communication systems (20) use repeaters (50) to communicate with subscriber units (24) otherwise shadowed from base stations (22). A networked repeater (50) is provided for use in a cellular communication system with low-earth orbit satellites (22) and mobile subscriber units (24). Networked repeater (50) includes a base transceiver module (54) for communicating with the base stations (22) and a plurality of subscriber transceiver modules (56), each of which communicates with subscriber units (24). The base transceiver module (54) is located so as to be unshadowed, i.e. able to have unimpeded communication with at least one of the satellites (22). The subscriber transceiver module (56) is located so as to provide unshadowed communication with the subscriber units (24) that would otherwise be shadowed, i.e. unable to have unimpeded communication with any of the satellites (22).

Abstract: A space-based communication system (30), includes a transmission terminal having a transmission antenna (42) and a power amplifier (40) to power the transmission antenna, the power amplifier to generate a power output sufficient to generate an RF signal through the transmission antenna (42), a receive terminal including a receive antenna (45) to receive the RF signal from the transmission terminal and a low noise amplifier (43) to amplify the RF signal channeled through the receive antenna, and a thermoelectric cooler (62) for cooling the low noise amplifier (43) to a predetermined temperature for increasing the sensitivity of the low noise amplifier to minimize the power output generated by the power amplifier required to generate the RF signal thereby minimizing the overall power requirements of the spaced-based communication system (30).

Abstract: A structure (24) includes a plurality of repeaters (34), each having a primary transceiver (36) and a secondary transceiver (38) electromagnetically located upon a clear side (30) and a blocked side (32), respectively, of a barrier (26). Each primary transceiver (36) and secondary transceiver (38) communicate using an intra-repeater signal (46). Each intra-repeater signal (46) is output from its respective primary transceiver (36), combined with other intra-repeater signals (46) by a combiner (50), passed over a communication infrastructure (22), separated from other intra-repeater signals (46) by a separator (54), and input to its respective secondary transceiver (38). Optionally, each intra-repeater signal (46) may be retrieved from the communication infrastructure (22), separated from other intra-repeater signals (46) by a separator (62), amplified by a bandpass amplifier (64), combined with other intra-repeater signals (46) by a combiner (66), and inserted back into the communication infrastructure (22).

Abstract: A method and apparatus for efficiently interconnecting a large number of high frequency high bandwidth signals includes two interface plates (100, 200), each having two substantially coplanar faces, a mating face (110, 210) and a non-mating face (120, 220). Each interface plate has waveguides (116, 216) disposed between the coplanar faces such that when the mating faces of the interface plates are brought together, a plurality of waveguide connections are made. An energy absorbing gasket (300) having a hole pattern matching the waveguide pattern is disposed between the mating faces of the interface plates so that reflections caused by misalignment and non-coplanarity of faces can be reduced.

Abstract: A radio-frequency circuit (20) includes a hybrid integrated circuit (24) having a passive circuit element (38) and a d-c biasing circuit element (54) embedded within a first substrate (32) of a low cost and rugged first semiconducting material, and first and second active circuit elements (36, 40) embedded within second and third substrates (44, 46), respectively, of a second semiconductor material having the characterisitics of greater frangibility but higher gain than the first semiconductor material. The first and second activ circuit elements (36, 40) are substantially first and second single components (36, 40), and are each electrically coupled to the passive circuit element (38). The d-c biasing circuit element (54) is electrically coupled to the first and second active circuit elements (36, 40). The second and third substrates (44, 46) are physically coupled to the first substrate (32), which is thicker than either the second or third substrate (44, 46).

Abstract: A harmonic generator (20) converts an input signal (24) at a fundamental frequency (28) into an output signal (32) at a harmonic frequency (34). A non-linear device (22) converts the input signal (24) into an intermediate signal (38) in which the harmonic frequency (34) has a maximized amplitude (40) determined by a conduction angle (26). A harmonic filter (68) produces a filtered signal (70) proportional to the amplitude (40) of the harmonic frequency (34) within the intermediate signal (38). A detector (80) produces a control signal (82) proportional to the amplitude of the filtered signal (70). A control circuit (84) produces a variable bias signal (50) for non-linear device (22), bias signal (50) being proportional to the amplitude of the control signal (82) and determining the conduction angle (26). An output filter (88) converts the intermediate signal (38) into an output signal (32) at the harmonic frequency (34).

Abstract: A MMIC power amplifier (100) uses MMIC FET cells (104, 112) and provides high gain at microwave and millimeter-wave frequencies. The power amplifier includes an input matching network (102), a first plurality of unit FET cells (104) for amplifying in-phase signals provided by the input matching network, a second plurality of unit FET cells (112), an interstage matching network (106) for combining output signals provided by the first plurality of unit FET cells, and providing in-phase signals to the second plurality of unit FET cells; and a combiner (113) for combining output signals of the second plurality of unit FET cells to provide an output signal. The FET cells are designed to be unconditionally stable without the use of an external series gate resistance. The FET cells are combined to provide total device periphery suitable for output power levels exceeding 0.8 watt at frequencies ranging from 19 to 23.5 GHz. The FET cells are designed using device scaling and device modeling techniques.