Abstract: A quantum communications system may include transmitter node, a receiver node, and a quantum communications channel coupling the transmitter node and receiver node. The transmitter node may be configured to co-propagate a first pulse for a quantum state and a second pulse to stabilize the quantum state through the quantum communications channel.

Abstract: Systems and methods for operating a receiver. The methods comprise: receiving, at the receiver, a combined waveform comprising a combination of a desired signal and an interference signal; and performing, by the receiver, demodulation operations to extract the desired signal from the combined waveform. The demodulation operations comprise: obtaining, by the receiver, machine learned models for recovering the desired signal from combined waveforms; comparing, by the receiver, at least one characteristic of the received combined waveform to at least one of the machine learned models; and determining a value for at least one symbol of the desired signal based on results of the comparing.

Abstract: A geospatial monitoring system may include a memory and a processor cooperating with the memory to obtain crowd-sourced mobile data (CSMD) for a geographic region, identify a plurality of geospatial sites within the geographic region based upon the CSMD, and determine a classification of each of the plurality of geospatial sites based upon the CSMD. The processor may further determine a pattern-of-life normalcy model for each of the geospatial sites based upon a respective classification, determine an abnormality in a respective pattern-of-life normalcy model at a given geospatial site based upon the CSMD, and initiate additional monitoring for the given geospatial site having the abnormality.

Abstract: A radio frequency (RF) system may include an RF transceiver and a baseband engine, application specific integrated circuit (ASIC) coupled to the RF transceiver and configured to perform a given baseband engine operation from among different baseband engine operations. The baseband engine ASIC may include a memory and a state machine coupled thereto and configured to store a respective set of programming instructions for each of different baseband engine operations and to permit selection of the given set of programming instructions. The baseband engine may also include a programmable processing circuit coupled to the memory and the state machine and configured to perform block coding computations responsive to the given set of programming instructions.

Abstract: A communications system may include a transmitter node, a receiver node, and an optical communications channel coupling the transmitter node and receiver node. The transmitter node may include a pulse transmitter and a pulse divider downstream therefrom. The receiver node may include a pulse recombiner and a pulse receiver downstream therefrom.

Abstract: An antenna device may include a ground plane, a first planar antenna element spaced above the ground plane and having an opening, and a second planar antenna element spaced above the first planar antenna element on a side of the first planar antenna element opposite the ground plane. The second planar antenna element may have a size smaller than the first planar antenna element. The antenna device may include a coaxial feed with an outer conductor, and an inner conductor surrounded by the outer conductor and extending outwardly from an end of the outer conductor. The outer conductor may be coupled to the ground plane and the first planar antenna element. The inner conductor may extend through the opening in the first planar antenna element and may be coupled to the second planar antenna element.

Abstract: An electronic device may include a circuit board, a heat generating component carried by the circuit board, a heat transfer rail extending along an edge of circuit board and coupled to the heat generating component, a housing covering the circuit board, and a heat transfer clamp between the heat transfer rail and the housing. The heat transfer clamp includes a flexible, heat conductive layer having a first portion in thermal contact with the heat transfer rail and a second portion in thermal contact with the housing. The first and second portions are thermally coupled, and a clamp and a compressible layer thereon extends between the first and second portions of the flexible, heat conductive layer.

Abstract: The optical system includes a base having a groove and an adjacent slot therein. The system also includes at least one optical cell slidably alignable along the groove, and at least one clamp comprising a lower end and an upper end. The lower end is slidably alignable along the slot and is secured at a set location so that the upper end secures the at least one optical cell along the groove. The slot may extend parallel to the groove. The clamp may include at least one preloaded fastener arrangement securing the lower end of the clamp to the base. The preloaded fastener may include a bolt, a spring biasing the bolt, and a threaded backing plate within the slot and receiving the bolt.

Abstract: A communications device may include an RF device having an operating frequency range, and an antenna coupled to the RF device and being electrically small with respect to the operating frequency range of the RF device. The communications device may include an active capacitor coupled between the RF device and the antenna. The active capacitor may include a settable operating curve with a decreasing capacitance versus increasing frequency over a portion of the operating frequency range of the RF device. The communications device may further include a control circuit coupled to the active capacitor to set the settable operating curve.

Abstract: A system may include a laser source, and an AOM coupled to the laser source. The AOM may include an acousto-optic medium, and transducer electrodes carried by the acousto-optic medium. The system may also include an interface board having a dielectric layer, and vertically extending signal vias within the dielectric layer. Each vertically extending signal via may have a lower end in contact with a respective transducer electrode. The interface board may have laterally extending signal traces carried by the dielectric layer. Each laterally extending signal trace may be in contact with an upper end of a respective vertically extending signal via.

Abstract: A quantum communications system may include a transmitter node, a receiver node, and a quantum communications channel coupling the transmitter node and receiver node. The transmitter node may include a pulse transmitter and a pulse divider downstream therefrom. The pulse divider may be configured to divide each pulse having a plurality of X photons into a plurality of Y time bins with Y>X. The receiver node may include a pulse recombiner and a pulse receiver downstream from the pulse recombiner.

Abstract: A docking system may include a first device and a second device moveable relative to the first device. The first device may include a docking station, a first optical transceiver, and a first controller configured to operate the first optical transceiver to receive an optical beacon signal, and generate and transmit an optical guidance data signal based on the optical beacon signal. The second device may also include a propulsion system, and a second optical transceiver configured to transmit the optical beacon signal toward the first optical transceiver and receive the optical guidance data signal from the first optical transceiver. The second device may also include a second controller configured to operate the propulsion system based upon the optical guidance data signal to dock the second device to the docking station of the first device.

Abstract: A communications system includes cellular devices and cellular base stations in communication with the cellular devices in a first frequency band. A non-geostationary satellite may include sensing circuitry operable in a second frequency band susceptible to interference from the first frequency band. Each cellular base station may include a controller and a transceiver cooperating therewith. The controller may be configured to store satellite path data for the non-geostationary satellite, determine when the satellite path data indicates interference would otherwise be experienced by the non-geostationary satellite, and implement an interference mitigation action in cooperation with associated cellular devices based upon the satellite path data indicating interference would otherwise be experienced by the non-geostationary satellite.

Abstract: An antenna may include a tower extending vertically upward from a ground location, a first set of elongate antenna elements extending outwardly from the tower at a first height above the ground location, and a second set of elongate antenna elements extending outwardly from the tower at a second height above the ground location and below the first height. In some embodiments, at least one elongate antenna element of the first and second sets of elongate antenna elements may be electrically coupled to the ground location. A radio frequency (RF) feed may be electrically coupled to the first and second sets of elongate antenna elements.

Abstract: A quantum communications system includes a communications system that operates with a quantum key distribution (QKD) system, which includes a transmitter node, a receiver node, and a quantum communications channel coupling the transmitter node and receiver node. The transmitter node may be configured to transmit to the receiver node a bit stream of optical pulses, and switch between first and second QKD protocols based upon at least one channel condition.

Abstract: A radio frequency (RF) system may include an RF transceiver, and a baseband engine, application specific integrated circuit (ASIC) coupled to the RF transceiver and configured to perform a given baseband engine operation from among different baseband engine operations. The baseband engine ASIC may include a memory and a state machine coupled thereto and configured to store a respective set of programming instructions for each of the different baseband engine operations and to permit selection of the given set of programming instructions. The baseband engine ASIC may also include a programmable processing circuit coupled to the memory and the state machine and configured to perform butterfly computations responsive to the given set of programming instructions.

Abstract: A satellite includes first and second extensible pantographic trusses, each configured to extend outwardly from the satellite in opposite directions from a stored position to a deployed position, and first and second sets of ribs carried by the respective first and second extensible pantographic trusses. A Radio Frequency (RF) reflective film may be carried by the first and second sets of ribs to define a curved RF reflector surface. The satellite antenna may include first and second sets of phased array antenna feeds carried by the respective first and second extensible pantographic trusses and directed toward the RF reflective film, which in an example may be a RF reflective mesh.

Abstract: Systems and methods for making a structure. The methods comprise: obtaining a composite tube structure; and coupling a tube doubler structure at any point along the composite tube structure. The tube doubler structure comprises a first lamina layer formed of a first material and a second lamina material formed of a second material different than the first material. The combination of the first and second materials provides a tube doubler structure with (i) a bulk bearing strength greater than a bearing strength of the composite tube structure and (ii) hoop and axial bulk Coefficient of Thermal Expansions respectively matching hoop and axial Coefficient of Thermal Expansions of the composite tube structure by a given amount.

Abstract: Systems and methods for providing a soldered interface between a circuit board and a connector pin. The methods comprise: using a jet paste dispenser to apply first solder into a plated contact cavity formed in the circuit board; using a stencil screen printer to apply second solder (a) over the plated contact cavity which was at least partially filled with the first solder by the jet paste dispenser and (b) over at least a portion of a pad surrounding the plated contact cavity; inserting the connector pin in the plated contact cavity such that the connector pin passes through the second solder and extends at least partially through the first solder; and performing a reflow process to heat the first and second solder so as to create a solder joint between the circuit board and the connector pin.

Abstract: A radar antenna for a flight vehicle that follows a flight path comprises a radio frequency (RF) reflector, and separated first arrays of first RF feed elements to form, with the reflector, respective first fixed radar beams that are directed at the Earth and positionally offset with respect to each other, such that when the radar antenna follows the flight path, the respective first fixed radar beams trace respective first subswaths on the Earth that are separated from each other by respective subswath gaps.