Abstract: The disclosed systems, structures, and methods are directed to an orbital angular momentum (OAM) receiver. The OAM receiver comprising at least three receiver antenna elements configured to receive radiated OAM-RF waves and generate antenna element output signals, a selection-antenna switch operative to receive and switch between a second receiver antenna element RX2a output and a third receiver antenna element output RX2b, a phase adjusting unit configured to adjust a phase of the output of the selection-antenna switch, a hybrid coupler configured to provide a proportional summation and difference of the two modulated signals, a switching unit configured to limit the coupler output signal to gating time-intervals during which fractional pseudo-Doppler frequency shifts occur, an orthogonal filter bank configured to generate a vector X(t) containing shifted low-frequency values associated with all of the K OAM modes, and an adaptive unit configured to facilitate separation of the OAM-RF waves.

Abstract: A feed network, steering apparatus and system for a steerable antenna array are described. The feed network includes a waveguide assembly including first and second radial transverse electromagnetic (TEM) waveguides, and first and second variable phase shifters positioned in the respective TEM waveguides. The variable phase shifters cause additional progressive electrical phase shifts in respective rings of radiating elements, directly proportional to the angular position of the radiating elements in the ring, from 0 to a controllable integer multiple of 2? radians. The feed network includes first and second phase-mode feed probes coupled to the respective radial TEM waveguides, which provide respective phase-mode feed ports. When the feed network is coupled to the antenna array, two consecutive-order phase modes are provided at the phase-mode feed ports. The orders of the phase modes are selectable using a phase shift control signal controlling the integer multiple of the variable phase shifters.

Abstract: A feed network, steering apparatus and system for a steerable antenna array are described. The feed network includes a waveguide assembly including first and second radial transverse electromagnetic (TEM) waveguides, and first and second variable phase shifters positioned in the respective TEM waveguides. The variable phase shifters cause additional progressive electrical phase shifts in respective rings of radiating elements, directly proportional to the angular position of the radiating elements in the ring, from 0 to a controllable integer multiple of 2? radians. The feed network includes first and second phase-mode feed probes coupled to the respective radial TEM waveguides, which provide respective phase-mode feed ports. When the feed network is coupled to the antenna array, two consecutive-order phase modes are provided at the phase-mode feed ports. The orders of the phase modes are selectable using a phase shift control signal controlling the integer multiple of the variable phase shifters.

Abstract: The disclosed systems, structures, and methods are directed to a multiple-input multiple-output (MIMO) receiver. The MIMO receiver includes at least two receiver antenna elements to receive radiated MIMO signal beams containing superposed order modes and to generate antenna element output signals based on the received MIMO signal beams. The receiver antenna elements are spatially separated by a distance. A variable ratio combining unit operates to switch between the antenna output signals based on a high-rate periodic waveform that emulates unidirectional movement by the antenna elements to produce a pseudo-Doppler frequency shift. The variable ratio combining unit further modulates the antenna output signals based on the periodic waveform to impart a fractional pseudo-Doppler shift to each MIMO mode and combines the modulated antenna element output signals in accordance with the fractional pseudo-Doppler shift to facilitate separation of the MIMO modes.

Abstract: The disclosed systems, structures, and methods are directed to an orbital angular momentum (OAM) receiver. The OAM receiver includes at least two receiver antenna elements to receive radiated OAM signal beams containing superposed order modes and to generate antenna element output signals based on the received OAM signal beams. The receiver antenna elements are positioned tangentially along a circular locus and spatially separated by a distance. A variable ratio combining unit operates to switch between the antenna output signals based on a high-rate periodic waveform that emulates unidirectional movement by the antenna elements to produce a pseudo-Doppler frequency shift. The variable ratio combining unit further modulates the antenna output signals based on the periodic waveform to impart a fractional pseudo-Doppler shift to each OAM mode and combines the modulated antenna element output signals in accordance with the fractional pseudo-Doppler shift to facilitate separation of the OAM modes.

Abstract: An antenna that includes a radial waveguide defining a waveguide region between opposed first and second surfaces. A radio frequency (RF) probe is disposed in the waveguide region for generating RF signals, and a plurality of radiating slot antenna elements are disposed on the first surface for emitting the RF signals from the waveguide region. A plurality of spaced apart conductive elements are disposed within the waveguide region. The antenna includes tunable elements that each include a quarter wavelength RF choke coupled through a variable capacitance and an inductive line to a respective one of the conductive elements. A plurality of DC control lines are provided, with each DC control line being connected to at least one of the tunable elements to adjust the variable capacitance thereof.

Abstract: A sparse phase-mode feed network for an antenna array is described. The waveguide assembly includes a plurality of radiating element probes for coupling to respective radiating elements of the antenna array, and a plurality of phase-mode feed probes. A variable phase shifter is positioned in the waveguide assembly in an annular region between the radiating element probes and the phase-mode feed probes to cause additional progressive electrical phase shifts of the radiating elements of the antenna array from 0 to 2?K radians, the phase shift progressing for one complete physical angular cycle in the plane of the waveguide assembly. A beam forming network couples the phase-mode feed probes to a plurality of phase-mode feed ports corresponding to respective consecutive-order phase modes of the antenna array. When coupled to the antenna array, respective orders of the phase modes provided at the phase-mode feed ports are selectable in accordance with K.

Abstract: A feed network, steering apparatus and system for a steerable antenna array are described. The feed network includes a waveguide assembly including first and second radial transverse electromagnetic (TEM) waveguides, and first and second variable phase shifters positioned in the respective TEM waveguides. The variable phase shifters cause additional progressive electrical phase shifts in respective rings of radiating elements, directly proportional to the angular position of the radiating elements in the ring, from 0 to a controllable integer multiple of 2? radians. The feed network includes first and second phase-mode feed probes coupled to the respective radial TEM waveguides, which provide respective phase-mode feed ports. When the feed network is coupled to the antenna array, two consecutive-order phase modes are provided at the phase-mode feed ports. The orders of the phase modes are selectable using a phase shift control signal controlling the integer multiple of the variable phase shifters.

Abstract: A method and apparatus for phase-mode feeding a circular antenna array for beamsteering is provided. A Butler Matrix having M antenna-side ports and M input/output ports is coupled to beamsteering circuitry. The coupled input/output ports may include a port corresponding to a phase-mode having an order magnitude greater than one. The coupled input/output ports may include ports of three different order magnitudes of phase-mode. The Butler Matrix is coupled to M inner ports of a radial waveguide, and the antenna elements are coupled to N outer ports of the waveguide, where N>M. Where M=4, the input/output ports correspond to a zeroth order phase-mode, plus and minus 1st order phase-modes, and a second order phase-mode. The zeroth order phase-mode may be used for beamsteering closer to the radial axis of the antenna array while the second order phase-mode may be used for beamsteering further from the radial axis.

Abstract: An antenna that includes a radial waveguide defining a waveguide region between opposed first and second surfaces. A radio frequency (RF) probe is disposed in the waveguide region for generating RF signals, and a plurality of radiating slot antenna elements are disposed on the first surface for emitting the RF signals from the waveguide region. A plurality of spaced apart conductive elements are disposed within the waveguide region. The antenna includes tunable elements that each include a quarter wavelength RF choke coupled through a variable capacitance and an inductive line to a respective one of the conductive elements. A plurality of DC control lines are provided, with each DC control line being connected to at least one of the tunable elements to adjust the variable capacitance thereof.

Abstract: A sparse phase-mode feed network for an antenna array is described. The waveguide assembly includes a plurality of radiating element probes for coupling to respective radiating elements of the antenna array, and a plurality of phase-mode feed probes. A variable phase shifter is positioned in the waveguide assembly in an annular region between the radiating element probes and the phase-mode feed probes to cause additional progressive electrical phase shifts of the radiating elements of the antenna array from 0 to 2?K radians, the phase shift progressing for one complete physical angular cycle in the plane of the waveguide assembly. A beam forming network couples the phase-mode feed probes to a plurality of phase-mode feed ports corresponding to respective consecutive-order phase modes of the antenna array. When coupled to the antenna array, respective orders of the phase modes provided at the phase-mode feed ports are selectable in accordance with K.

Abstract: A method for operating a beam-steering system includes receiving a signal to be tracked, generating a first phase-mode signal, a second phase-mode signal and a third phase-mode signal from the received signal, and generating a first intermediate auxiliary signal, a second intermediate auxiliary signal, and a first intermediate main signal in accordance with the phase-mode signals. The method also includes deriving a first steering signal proportional to a circumferential steering angle of the received signal from the first intermediate main signal and the first auxiliary signal, and deriving a second steering signal proportional to a radial steering angle of the received signal from the second intermediate auxiliary signal and the first intermediate main signal.

Abstract: Beam-steering for a 2-dimensional array of an arbitrary number of radiating elements around both possible axes may be accomplished using a limited number of control components. By selectively coupling signal lines to different feed ports of the antenna array's feed network, it is possible to steer the main beam.

Abstract: Beam-steering for a 2-dimensional array of an arbitrary number of radiating elements around both possible axes may be accomplished using a limited number of control components. By selectively coupling signal lines to different feed ports of the antenna array's feed network, it is possible to steer the main beam.

Abstract: A noise cancellation method comprises receiving, by an adaptive phase-noise cancellation apparatus, a noise-corrupted symbol from a receiver, performing a hard decision process on the noise-corrupted symbol to generate a substantially clean symbol based upon the noise-corrupted symbol, calculating a phase deviation of the noise-corrupted symbol based upon the substantially clean symbol and the noise-corrupted symbol, generating a phase error based upon the phase deviation and transmitting, at an output of the adaptive phase-noise cancellation apparatus, a phase corrected symbol determined in accordance with a subtraction of the generated phase error from the received noise-corrupted symbol.

Abstract: System and apparatus embodiments are provided for sparse phase-mode planar feed for circular arrays of transducing elements for a beam-steering antenna system. In an embodiment, a sparse phase-mode feed for an array of antenna elements includes an electrically conducting first disk; an electrically conducting second disk parallel to and coaxial with the first disk; an electrically conducting outer wall; a plurality of phase-mode feed probes, wherein at least a portion of the phase-mode feed probes are electrically coupled to the first disk, and wherein the phase-mode feed probes are symmetrically arranged around the center of the first disk; and antenna-element probes, wherein at least a portion of the antenna-element probes are electrically coupled to the second disk, and wherein the antenna-element probes are symmetrically arranged on an outer portion of the second disk, wherein the number of phase-mode feed probes is less than the number of antenna element probes.

Abstract: System and apparatus embodiments are provided for beam-steering. In an embodiment, an apparatus includes a first hybrid splitter/combiner connected to a 0-th phase-mode feed of an array of antenna elements, a second hybrid splitter/combiner, a first pair of variable phase shifters connecting the first hybrid splitter/combiner to the second hybrid splitter/combiner, wherein the first pair of variable phase shifters control a steering direction of a main output beam radial with respect to an array axis by adjustments of respective phases of the variable phase shifters, and wherein the array axis is perpendicular to a plane of the array, and a third variable phase shifter connecting a 1-st phase-mode feed of an array of elements to an input of the first hybrid splitter/combiner, wherein the third variable phase shifter is configured to independently control a direction of the main output beam in a direction circumferential with respect to the array axis.

Abstract: A noise cancellation method comprises receiving, by an adaptive phase-noise cancellation apparatus, a noise-corrupted symbol from a receiver, performing a hard decision process on the noise-corrupted symbol to generate a substantially clean symbol based upon the noise-corrupted symbol, calculating a phase deviation of the noise-corrupted symbol based upon the substantially clean symbol and the noise-corrupted symbol, generating a phase error based upon the phase deviation and transmitting, at an output of the adaptive phase-noise cancellation apparatus, a phase corrected symbol determined in accordance with a subtraction of the generated phase error from the received noise-corrupted symbol.

Abstract: A method for operating a beam-steering system includes receiving a signal to be tracked, generating a first phase-mode signal, a second phase-mode signal and a third phase-mode signal from the received signal, and generating a first intermediate auxiliary signal, a second intermediate auxiliary signal, and a first intermediate main signal in accordance with the phase-mode signals. The method also includes deriving a first steering signal proportional to a circumferential steering angle of the received signal from the first intermediate main signal and the first auxiliary signal, and deriving a second steering signal proportional to a radial steering angle of the received signal from the second intermediate auxiliary signal and the first intermediate main signal.

Abstract: A noise cancellation method comprises receiving, by an adaptive phase-noise cancellation apparatus, an incoming symbol from a receiver, performing a hard decision process on the incoming symbol to generate a corresponding clean symbol of the incoming symbol, generating a conjugate instance of the corresponding clean symbol, multiplying the orthogonal instance of the incoming symbol by the conjugate instance of the corresponding clean symbol to generate an intermediate component and calculating a phase deviation of the incoming symbol based upon a real part of the intermediate component and an imaginary part of the intermediate component.