Abstract: A mainlobe detection process can include a number of tests that are performed to define when the monopulse antenna system will transition from open loop scanning to closed loop scanning and then to tracking. A hybrid tracking technique is also provided which adaptively discovers and corrects for phase alignment error. Magnitude-only tracking can be performed initially to locate the nulls in the azimuth and elevation ratios and to identify the magnitudes of these ratios at these nulls. Phase tracking can be then performed. During phase tracking, phase corrections can be repeatedly applied to the azimuth and elevation difference channels to correct any phase error that may exist. During this process, the magnitudes of the ratios can be used to determine how the phase corrections should be adjusted. Once the hybrid tracking process is complete, the monopulse antenna system is properly phase-aligned and phase tracking will be correctly employed.

Abstract: Embodiments include different multi-port ring combiners which are configured to act as multi-output signal routers. One type of multi-port ring combiner includes input ports that are driven by pairs of outphasing signals. The multi-port ring combiner also includes multiple channels that are independently routed to a first output, to a second output, or to a third output, according to a phase relationship of the multi-port ring combiner. The multi-port ring combiner enables an outphasing signal combination which provides output port selection. The multi-port ring combiner may be a 4-port ring combiner, a 5-port ring combiner or a 6-port ring combiner.

Abstract: A mainlobe detection process can include a number of tests that are performed to define when the monopulse antenna system will transition from open loop scanning to closed loop scanning and then to tracking. A hybrid tracking technique is also provided which adaptively discovers and corrects for phase alignment error. Magnitude-only tracking can be performed initially to locate the nulls in the azimuth and elevation ratios and to identify the magnitudes of these ratios at these nulls. Phase tracking can be then performed. During phase tracking, phase corrections can be repeatedly applied to the azimuth and elevation difference channels to correct any phase error that may exist. During this process, the magnitudes of the ratios can be used to determine how the phase corrections should be adjusted. Once the hybrid tracking process is complete, the monopulse antenna system is properly phase-aligned and phase tracking will be correctly employed.

Abstract: A monopulse antenna system can include a monopulse detector assembly (MDA) that is configured to steer a monopulse antenna based on the magnitude of an elevation ratio or azimuth ratio independently of the phase of the ratio. To prevent the direction of the monopulse antenna from being changed too frequently, the MDA can employ ratio bins to determine when the direction of the monopulse antenna should be reversed. Also, the MDA may enforce a hold period during which a change in the direction of the monopulse antenna will not be performed. The MDA can employ one or more mapping equations to generate a steering signal as a function of the magnitude of the ratio. The mapping equations can be selectively employed based on whether tracking is being performed at or near the ratio null.

Abstract: A monopulse tracker includes multiple dual-axis monopulse antenna systems that are angled with respect to one another. The orientations of the monopulse antenna systems create a much larger field of view for the monopulse tracker to eliminate the need to steer the monopulse tracker. The monopulse tracker can be configured to estimate a position of an object based on tracking information received from more than one monopulse antenna system therefore increasing the accuracy of the estimated position. The multiple monopulse antenna systems can be arranged in a low-profile housing to facilitate use of the monopulse tracker on aircraft.

Abstract: A transmitter or receiver can include a phased array antenna system in which multiple characteristics of a transmitted or received beam can be controlled electronically. For example, in embodiments that include a transmitter, dual outputs of N signal modifiers can be connected to orthogonal inputs of N dual-orthogonally polarized antenna elements. Each signal modifier can modify the amplitude and phase of a communications signal in two parallel signal paths to produce two signal components each of which is an amplitude-modified/phase-shifted version of the communication signal. Multiple characteristics of the combined beam can be simultaneously controlled by setting the amplitude and/or phase-shift parameter values in the dual signal paths in the signal modifiers to combined values that individually affect each of the multiple characteristics of the combined beam.

Abstract: A block of ordered data elements comprising a plurality of sub-blocks each of which is to be processed by a different processing module in segments of the data elements having a particular length characteristic can be received in parallel streams on parallel communication channels. The data elements in each stream can be received and directed to the corresponding processing module. The tail of a segment split between two of the streams and received earlier in time than the corresponding head of the split segment can be buffered until the head is received on the other stream. The head and the tail of the split segment can then be processed as a whole segment in a corresponding processing module.

Abstract: The presence of a hidden signal can be detected efficiently using frequency domain multiplication. A detector system can be employed to search for a hidden signal across a wide spectrum in real time. The detector system can divide multiple antenna inputs into a series of blocks and then convert these blocks to the frequency domain possibly in a parallel fashion. Corresponding blocks from each input can then be conjugate multiplied, and the results of this conjugate multiplication can then be averaged over time. If a signal is hidden in the inputs, this averaging will reduce the noise floor thereby revealing the presence of the hidden signal at a particular frequency.

Abstract: A digital transmitter channel optimization device can be employed within or in conjunction with a transmitter to perform a number of techniques in the digital domain to account for distortion introduced in the transmitter. The optimization device can be configured to perform such techniques on an arbitrary signal to thereby allow the optimization device to be used with virtually any transmitter. The optimization device may be particularly beneficial in wideband systems where accounting for distortion can be difficult to accomplish using existing techniques.

Abstract: An antenna system can impart orbital angular momentum (OAM) to an incident electromagnetic (EM) signal from a feed antenna. The antenna system can include a partial OAM antenna with a reflective surface that has only part of a full OAM shaped surface. The antenna system can thus reflect the incident EM signal as a partial OAM beam rather than a full OAM beam.

Abstract: A method for acquiring and tracking an in-flight or airborne target using an antenna is provided. In the acquisition process, the antenna is rotated to collect RF power data. The location of peak RF power is determined and the antenna is pointed to that location. The antenna may then undergo a search pattern on either side of that location to detect a specified drop in RF power and a modem on which to lock. In the tracking process, an algorithm allows the antenna to track the target in a pure RF mode, a GPS-based open loop pointing mode or a hybrid mode. The tracking may automatically switch between the pure RF mode and the hybrid mode, depending upon whether GPS data is available from the target.

Abstract: A configurable antenna may include a circular horn array comprising a plurality of horn antennas, a configurable waveguide in a center of the circular horn array, and a plurality of actuators. The configurable waveguide includes a plurality of retractable triangular wedges, with one side of each wedge oriented to one of the plurality of horn antenna and a corner oriented toward a center of the waveguide, wherein a circle defined by each of the corners oriented toward the center of the waveguide defines a first circumference. The configurable waveguide further includes a plurality of movable tuning rods arranged in a circle defining a second circumference, the second circumference being smaller than the first circumference, said movable tuning rods further arranged such that the movable tuning rods are between the corners the corners oriented toward the center of the waveguide.

Abstract: A content addressable memory (CAM) system can include a comparator core in which all of the keys of the CAM are embedded in comparator blocks. A search key can be provided to each of the comparator blocks, which can compare the search key to its embedded key and determine whether the search key matches the embedded key. The comparator blocks can be organized into paged sets in the comparator core such that only one of the comparator blocks in each paged set is selected and compares its embedded key to the search key at any given time. The comparator block selected in each paged set can be incremented until the search key has been compared to the keys embedded in all of the comparator blocks of the comparator core.

Abstract: An LDPC decoder includes a check node processor. The check node processor is configured to implement an n-degree check node, where n is a predetermined number. The degree of a check node is the number of edges coupled to the check node. The LDPC decoder also includes a plurality of n time division multiplexers coupled to the check node processor to couple different edge connection input values to the check node processor at different times so as to allow the check node processor to be time division multiplexed for use in implementing different check nodes with the same check node processor. Each of the multiplexers is configured to provide no more than one edge connection input value to the check node processor at any given time. Each edge connection is used to implement an edge into a check node.

Abstract: Electromagnetic (EM) feeds can illuminate a standard primary reflective antenna with a plurality of feed beams each having a different orbital angular momentum (OAM) or polarization. The reflective antenna, which can be a non-OAM antenna, can reflect the feed beams and thereby produce a composite OAM transmission comprising each of the feed beams. A non-OAM primary antenna can thus transmit a plurality of OAM feed beams as a composite OAM transmission.

Abstract: A method for receiving and removing co-channel interference from one or more received signals that comprise different symbol or chipping rates can comprise receiving a first composite signal and a second composite signal. The method can also comprise sampling the first composite signal and the second composite signal at a particular sampling rate that is sufficient to recover signal data from both the first composite signal and the second composite signal. Further, the method can comprise estimating from the second composite signal an estimated cross-coupled second signal within the first composite signal. The estimated cross-coupled second signal is estimated from at least the second composite signal at the particular sampling rate. Further still, the method can comprise recovering a substantially decoupled first data signal by removing at least a portion of the co-channel interference caused by the estimated cross-coupled second signal from the composite first signal.

Abstract: A data alignment method is provided by iteratively increasing the delay of each data input line of a system component until a test signal transmitted on each data input line is received at the system component at substantially a predetermined time.

Abstract: Adaptive filtering is used to substantially cancel distortion in radio frequency (RF) signals. Such adaptive filtering can be used in an RF transmitting module to pre-compensate an RF signal with compensation (inverse) distortion to cancel inherent transmission path distortion from the RF signal. Adaptive filtering can also be used in a multi-carrier RF receiving module to cancel from a given carrier signal distortion due to cross talk from adjacent carrier signals. Adaptive filtering in an RF transceiver can be used to cancel from a received RF signal distortion arising from leakage of a transmit signal into the receive path.

Abstract: A circuit card can include a circulator for routing a signal from a first amplifier to an antenna and for routing a signal from the antenna to a second amplifier, replacing a traditional transfer switch. The circulator can be a surface mount element to enable the circulator, first amplifier, and second amplifier to be mounted on the same circuit card thereby minimizing the size of a transceiver that employs the circuit card. Multiple circulators can be included on the same circuit card to allow for multi-band operation.

Abstract: A horn-reflector antenna for tracking the location of in-flight aircraft is provided. The antenna includes an upwardly-opening horn having a reflector attached thereto. The horn may have an asymmetric rectangular cross-section and comprise at least one upwardly and outwardly extending side wall. The reflector includes a reflecting surface that may have a generally hyperbolic paraboloid shape or saddle shape. The horn and reflector may be constructed from a polymer material in an injection molding process. The reflecting surface of the reflector and the inner surfaces of the horn may be coated with a reflective or conductive material, for example, a paint comprising sliver-plated copper particles. In use, the horn-reflector antenna may be adapted to rotate around the longitudinal axis of a stationary waveguide feed. As such, the antenna of the present invention can be adapted for operation without the use of a rotary joint or a slip ring.