Abstract: A satellite transmitter module for accepting input signals and emitting output signals for uplink transmission. The module includes a transmitter unit that includes i) transmitter circuitry, ii) at least one input port, iii) and at least one output port. At least one heat sink coupled to the transmitter unit includes a plurality of heat sink fins, wherein at least two of the plurality of heat sink fins are of different heights. A fan is capable of generating air flow parallel with the plurality of heat sink fins. The module further includes an outer enclosure that i) encloses the transmitter unit and the plurality of heat sink fins and ii) is impermeable to the air flow generated by the fan. The outer enclosure includes an enclosure cross section shape that is substantially similar to the at least one heat sink cross section shape defined by the height of each of the plurality of the heat sink fins.

Abstract: [Object] A wireless communication system capable of detecting propagation path modification from the outside and compensating for degradation of quality of communication between transmission and reception with respect to the propagation path modification is provided. A wireless communication system includes a transmitter that transmits electromagnetic waves in which a polarization direction rotates according to a signal in which data is loaded on a carrier, and a receiver that receives the electromagnetic waves and demodulates the data, in which the transmitter imparts angle information indicating a polarization direction for transferring the data to the signal, and sets a rotation frequency of the polarization direction to a frequency lower than a frequency of the carrier, and the receiver changes a polarization direction of the received electromagnetic waves, based on the angle information transferred by the electromagnetic waves.

Abstract: An array antenna includes at least two antenna elements that are axially-aligned and axially-spaced. Polarization diversity is provided by at least one driven antenna element that provides horizontal and vertical polarizations. The driven element includes one or more feed points for the horizontal polarization and one or more feed points for the vertical polarization. A switching circuit is configured to switch between the one or more feed points to alternately provide the horizontal and vertical polarizations.

Abstract: A multi-port radiator radiates electromagnetic signal in response to a beat frequency of a pair of optical signals. The radiator includes a multitude of optical paths each carrying an optical signal having first and second wavelengths. A multitude of frequency conversion elements convert the optical signals to electrical signals and deliver them to the radiator's multiple ports. The frequency of the electrical signals, and hence the frequency of the electromagnetic wave, is defined by the difference between the first and second wavelengths. The phases of the optical signals received by the frequency conversion elements are shifted with respect to one another. Optionally, the difference between the phases of the optical signals travelling through each pair of adjacent paths is 90°. The first and second wavelengths are generated by a pair of optical sources and are optionally modulated before being combined and delivered to the optical paths.

Abstract: Small anechoic chambers for evaluating a wireless device under test (DUT) are characterized by a set of antennas to which a test signal is applied and for which excitation coefficients are applied such that the test signal approximates a single plane wave or a preselected superposition of plane waves in the near field of the antennas. The test-equipment antennas in the chamber may be as close as one wavelength from the boundary of a test zone in which the DUT is disposed. Hence, the test zone can be in the near field of the test-equipment antennas and the test zone can be less than a wavelength from the chamber walls. Consequently, it is possible to perform tests in a small anechoic chamber that previously required a large anechoic chamber, e.g., advanced spatial channel-model tests and antenna-pattern measurements.

Abstract: A radio transmitter used to transmit an activation signal for radio tags held by individuals or the like provides multi-dimensional polarization to an activation signal so as to allow more consistent range detection of an individual with a tag having a single axis of sensitivity. Circular or spherical polarization can be obtained using the system which may include an antenna design permitting decoupling of antennas necessary for the polarization, a quadrature locking system simplifying proper phase control of the necessary signals and a system for tuning the same.

Abstract: A method for processing an intranet includes crawling the intranet to identify at least some of the pages in the intranet, and determining, for each identified page, a number of links in a shortest path from a root page to the identified page.

Abstract: An optical radar device for scanning an object that reduces the effects of stray light is provided. The optical radar device has a light source, a light scanning section, a light path change section, a light receiver, and an opposite phase signal adder. The opposite phase signal adder adds an opposite phase signal to the output signal from the light receiver. A rise timing of the opposite phase signal is delayed by a predetermined time relative to an output timing of the pulse light, and the opposite phase signal has an opposite phase with respect to a phase of the reflected light.

Abstract: According to various embodiments, systems and methods are provided for improving signal quality and signal reliability over wireless communication using polarization diversity. Some embodiments use polarization diversity on a wireless channel to address and compensate for fading conditions such as non-frequency selective fading (also referred to as power fading, attenuation fading, and flat fading) and frequency selective fading (also referred to as multipath fading and dispersive fading). For example, some embodiments utilize a horizontal signal and a vertical signal on the same wireless channel when wirelessly communicating data between a transmitter and a receiver to address a fading condition.

Abstract: The present invention describes methods and apparatus for adaptive polarization transmission. An exemplary embodiment of the present invention provides an adaptive polarization transmission method. The method includes the step of analyzing at a transmitter device a first set of polarization state information relating to a first wireless signal path. Furthermore, the method includes the step of adapting a transmission signal to be distributed by the transmitter device based on at least the first set of polarization state information. In addition to adaptive polarization transmission methods, the present invention provides various adaptive polarization transmission systems. In an exemplary embodiment, an adaptive polarization transmission system includes a transmitter device. The transmitter device includes an analyzing unit for processing a first set of polarization state information relating to a first wireless signal path.

Abstract: Disclosed is a method to transmit multiple linear electromagnetic signals on a same frequency. For N data signals Si, where i=1 through N, each data signal is transmitted at 180/N degrees rotation from the next. For each data signal Si, signals inverse to Si are transmitted at +180/N degrees and ?180/N degrees from Si, rotated around the transmit axis, at a power level of 0.5/COS (180°/N) times the power of said Si signal. This results in cancellation of said data signal Si along the transmit rotation of Si and a receivable data signal inverted and at a 90 degrees rotation from said transmitted Si. A total of N distinct data signals are transmitted simultaneously on a same frequency, resulting in a dramatic increase in capacity in an electromagnetic system. N is an integer greater than one and could be, for example, 18.

Abstract: A leaky dielectric travelling wave surface waveguide antenna provides a multiband, low-profile antenna for satellite and other wideband (Ku/K/Ka/Q) communications applications. The antenna structure can be arranged into various types of arrays to yield a cost-effective, wideband/multiband operation with high power. In one implementation, the antenna includes a waveguide having a multi-layer substrate, a top surface, a feed (excitation) end, and a load end. One or more scattering features are disposed on the top surface of the waveguide or within the waveguide, and achieve operation in a leaky propagation mode. A wavelength correction element adds linear delay to incident energy received or transmitted by the antenna. The resulting structure permits a resulting beam direction of the antenna to be independent of the wavelength.

Abstract: The present invention relates to a method of generating two beams, having orthogonal polarizations, covering a selected area using an antenna (20) comprising multiple dual-polarized array elements (11). Each dual-polarized array element having a first phase center (18) associated with a first polarization and a second phase center (18) associated with a second polarization. The method comprises: designing a first weight matrix having a first non-zero weight vector for the first polarization and a second non-zero weight vector for the second polarization, calculating a second weight matrix based on the weight vectors of the first weight matrix, and applying the first and second weight matrix to the dual-polarized array elements to generate a second beam covering the selected area.

Abstract: There are provided a method and apparatus for transmitting and receiving signals in the same frequency band at the same time. A signal is received using a dual polarization antenna, the main axis of the polarization of the reception signal is predicted by performing adaptive polarization tracking, and polarization filtering is performed in order to remove interference. A signal is transmitted through a polarization completely orthogonal to the tracked polarization. In accordance with the present invention, in a wireless communication system, signals can be transmitted and received in the same frequency band at the same time.

Abstract: A ground-based antenna system includes a first phased array antenna to generate a first directional antenna beam at a first polarization, and a second phased array antenna to generate a second directional antenna beam at a second polarization. The first and second phased array antennas each include a lower antenna element row, an upper antenna element row, and medial antenna element rows therebetween. The ground-based antenna system further includes first and second antenna beam controllers cooperating with the first and second phased array antennas to generate a more steeply sloped phase taper associated with the lower antenna element row, a less steeply sloped phase taper associated with the medial antenna element rows, and a more steeply sloped phase taper associated with the upper antenna element row.

Abstract: A method is provided for generating and transmitting a test signal for an over-the-air test of a device-under-test that is in simulated motion. The method includes dithering Doppler shifts of a carrier frequency of the test signal on sub-path components of the test signal to produce slightly different frequencies per sub-path component, wherein the sub-path components are at a first and second polarization orientations. Dithering Doppler shifts can include dithering a first sub-path component at the first polarization orientation while keeping this sub-path component at the second polarization orientation at the original Doppler shift of the carrier frequency of the test signal, or keeping a first sub-path component at the first polarization orientation at the carrier frequency of the test signal while dithering this sub-path component at the second polarization orientation. Dithering Doppler shifts can include dithering sub-path components at the first and the second polarization orientation.

Abstract: A wideband frequency selective polarizer is provided. The wideband frequency selective polarizer includes arrays of first-frequency slots in at least two metallic sheets in at least two respective planes; and arrays of second-frequency slots interspersed with the arrays of first-frequency slots in the at least two metallic sheets in at least two respective planes. A polarization of a first-frequency radio frequency (RF) signal in a linearly-polarized-broadband-RF signal that propagates through the at least two planes is one of: rotated by a first angle in a negative direction; or un-rotated. A polarization of a second-frequency-RF signal in the linearly-polarized-broadband-RF signal is rotated by a second angle in a positive direction.

Abstract: A method and apparatus for electronically steering an antenna system. The apparatus comprises a dielectric substrate, a plurality of radiating spokes, and a number of surface wave feeds. The plurality of radiating spokes is arranged radially with respect to a center point of the dielectric substrate. Each radiating spoke in the plurality of radiating spokes forms a surface wave channel configured to constrain a path of a surface wave. Each of the number of surface wave feeds couples at least one corresponding radiating spoke in the plurality of radiating spokes to a transmission line that carries a radio frequency signal.

Abstract: An emission/reception installation of satellite signals including a reflector to receive and emit radio signals, a unit integrating an LNB to transform radio signals into electrical signals in a first frequency band, to amplify the electrical signals in the first frequency band and to lower the first frequency band towards a first intermediate frequency band. The unit includes an emitter to amplify electrical signals in a second intermediate band having no common frequency with the first intermediate band, to raise the second intermediate band towards a second frequency band, to transform into radio signals the electrical signals in the second frequency band and to transmit these radio signals towards the reflector. The installation includes a box including a modulator to modulate electrical signals in the second intermediate band, an output to transmit electrical signals in the first intermediate band and a coaxial cable connecting the unit and the box.

Abstract: Systems and methods for providing a MIMO capable antenna with unique properties are provided herein. In some embodiments, a 4×4 MIMO capable antenna is provided with unique properties. Circular polarization from the antennas ensures that both vertical and horizontal polarizations are energized to the full extent provided by local regulations. A system includes a radio and a plurality of antennas coupled to the radio, the plurality of antennas servicing a broadcast area that has a 360 degree coverage area. Each of the plurality of antennas transmits and receives in an isolated sub-sector of the 360 degree coverage area.

Abstract: Signal quality of a composite received signal in a radio communication network is optimized by adjusting a phase offset between received and/or transmitted signals based on signal quality parameters of the received and/or transmitted signals. The phase offset is adjusted by varying the phase offset between the received or transmitted signals such that that the composite signal is circularly, elliptically, or linearly polarized. The phase offset between the received or transmitted signals is continually adjusted based on the received signal quality parameters.

Abstract: A method of optimizing an antenna system can include determining a desired angle to rotate an antenna based on an axial ratio of electromagnetic waves exiting a radome that surrounds the antenna. The desired angle can be determined by a computing device based on a set of axial ratio values.

Abstract: An antenna system includes: an orthogonal multi-polarization antenna configured to output independent double orthogonal polarizations through two independent input/output terminals; an antenna main control unit configured to perform a polarization control algorithm, collect and analyze information for polarization control, and provide polarization control information; and a polarization control unit configured to perform independent amplitude and phase control with regard to a pair of independent channels connected to the orthogonal multi-polarization antenna, based on the polarization control information received from the antenna main control unit, so that various polarizations are formed.

Abstract: Provided are a device and method for estimating carrier frequency offset of OFDM signals transmitted and received through a plurality of polarized antennas that may accurately estimate carrier frequency offset used for carrier frequency synchronization acquisition when there is interference between polarized waves.

Abstract: A scalable, high-bandwidth connectivity architecture for portable storage devices and memory modules may utilize EHF communication link chip packages mounted in various two-dimensional and three-dimensional configurations on planar surfaces such as printed circuit boards. Multiple electromagnetic communication links between devices distributed on major faces of card-like devices may be provided with respectively aligned pairs of communication units on each device. Adjacent communication units on a printed circuit board may transmit or receive electromagnetic radiation having different polarization, such as linear or elliptical polarization. Power and communication between communication devices may both be provided wirelessly.

Abstract: A system for allowing ground terminals, specifically mobile ground terminals, to dynamically and electronically realign signal polarizations to match that of incoming and outgoing signal polarizations from designated space assets, specifically communications from satellites, comprising an adaptive re-orientation technique based on a cost minimization function, and a means of direct calculations of weighting components based on the knowledge of the orientation and bearing of both the satellites and the ground terminals. The embodiment will allow a mobile ground terminal to electronically realign itself to the signals of a satellite, without the need for mechanical processes to physically re-orient the antenna array.

Abstract: A device and method for determining a distance and/or orientation of a movable object includes a transmitter that is located on the object and a receiver. One of the transmitter and the receiver has an antenna having a known polarization plane. The other of the transmitter and the receiver has a counterclockwise circular polarized antenna and a clockwise circular polarized antenna.

Abstract: A signal source simultaneously emits horizontally polarized and vertically polarized signals and includes an enclosure, a power source and a signal generator received in the enclosure, and a first antenna and a second antenna set on an outer surface of the enclosure. The second antenna is perpendicular to the first antenna. The signal generator generates a comb-shaped signal having a predetermined frequency and the comb-shaped signal is split to two sub-signals of equal power by the signal generator, and the sub-signals are transmitted into a test environment via the first antenna and the second antenna.

Abstract: An electronic control module assembly includes antenna elements and a PCB. Each antenna element communicates an RF signal in a direction that corresponds with an outer face of a housing of the assembly. The PCB is received in a cavity of the housing and has RF-energy-transfer circuits and a baseband RF device, which demodulates the signal. Each RF-energy-transfer circuit receives the signal. At least two RF-energy-transfer circuits receive the signal from the antenna elements, and at least one RF-energy-transfer circuit does not receive the signal from one of the antenna elements and is a placeholder circuit. The baseband RF device is in communication with at least two of the RF-energy-transfer circuits receiving the signal. A connector provides a connection between each of the antenna elements and the PCB and is received by an aperture of the housing.

Abstract: The invention describes a method of actuating a switch (S) between a device (Di) to be controlled and a power supply (P), which method comprises the steps of generating a first electrical signal (14) in a remote control unit (10) and converting the first electrical signal (14) into electromagnetic radiation (EM) by means of a first transmitting antenna (Ti) of the remote control unit (10). A first detecting antenna (Ri) of a remote control interface module (20) of the device (Di) to be controlled detects the electromagnetic radiation (EM) to obtain a second electrical signal (24), which is passively converted into a switch actuating signal (25). The switch actuating signal (25) is actuated to switch the device (Di) to be controlled between an operating mode in which current is drawn from the power supply (P) by the device (Di) during operation, and an inactive mode in which the device (Di) is completely disconnected from the power supply (P) so that no current is drawn by the device (Di).

Abstract: A method of operating a multi-function phased array radar system having an antenna array populated with dual-pol antenna elements is described. The method includes selectively controlling individual dipoles of each dual-pol antenna element in order to operate the array in either a polarimetric mode with improved cross-pol isolation, or in a multi-mission mode, wherein a plurality of singularly-polarized signals are produced.

Abstract: A base station for use in a wireless communications system is disclosed, including transceiver circuitry for transmitting and receiving with at least one mobile device over at least one communications channel. Polarization control logic is included for controlling a polarization of signals transmitted over the at least one communications channel. The polarization control logic adjusts a polarization of the signal transmitted on the at least one communications channel responsive to at least one parameter received from the mobile device relating to a quality of signal received on the at least one communications channel.

Abstract: An antenna with polarization switching comprising a plurality of waveguides fed with radiofrequency signals and perforated with apertures disposed so as to illuminate radiating elements placed on mobile support means in a plane that is distant from the said apertures, it being possible for the said support means to be configured according to at least two distinct configurations. The radiating elements illuminated according to one and the same configuration are adjacent, the support means being adapted for orienting the radiating elements illuminated in a first configuration according to a different direction from the radiating elements illuminated in a second configuration. The antenna applies notably to the switching of antennas onboard objects moving on the ground required to undertake high-speed communications with a satellite, in particular a geostationary satellite.

Abstract: Disclosed are signal transmitting apparatus and method capable of generating polarizations that can be controlled in real time by allocating weights to signals. A signal transmitting method for generating variable polarizations having any vector through a plurality of radiating elements vertical to each other includes: receiving an input signal and separating the input signal into a plurality of separated signals according to the number of radiating elements; and allocating weights for controlling vectors of the variable polarizations to each of the plurality of separated signals, wherein the vectors of the variable polarizations are represented by a vector sum of the plurality of separated signals allocated with weights.

Abstract: Systems and methods for increasing communications bandwidth using non-orthogonal polarizations are provided herein. Under one aspect, a method of transmitting M independent signals, where M is at least 3, includes receiving the M signals from respective sources; at a transmitter polarization module, obtaining first and second linear combinations of the M signals; providing the first and second linear combinations to first and second input ports of a transmitter antenna; and transmitting with the transmitter antenna the first linear combination at a first polarization and the second linear combination at a second polarization orthogonal to the first polarization. The method may further include receiving at a receiver antenna the first linear combination at the first polarization, and the second linear combination at the second polarization; obtaining at receiver circuitry the M signals based on the received first and second linear combinations; and outputting the M signals on respective output ports.

Abstract: Signal quality of a composite received signal in a radio communication network is optimized by adjusting a phase offset between received and/or transmitted signals based on signal quality parameters of the received and/or transmitted signals. The phase offset is adjusted by varying the phase offset between the received or transmitted signals such that that the composite signal is circularly, elliptically, or linearly polarized. The phase offset between the received or transmitted signals is continually adjusted based on the received signal quality parameters.

Abstract: An onboard directional plane antenna comprises at least one array of radiating-slot waveguides comprising an alternating succession of three superposed metallic plates and of two dielectric substrates. The two substrates each comprise at least four adjacent waveguides, corresponding and communicating with one another pairwise by way of coupling slots. Each waveguide of the upper substrate furthermore comprises a plurality of radiating slots passing through the upper metallic plate, all the radiating slots of one and the same waveguide being parallel to one another and oriented in one and the same direction, the radiating slots of two adjacent waveguides being disposed in chevrons. Each waveguide of the lower substrate comprises an internal individual feed circuit comprising an individual electronic circuit for phase shifting and amplification.

Abstract: A intelligent backhaul radio have an advanced antenna system for use in PTP or PMP topologies. The antenna system provides a significant diversity benefit. Antenna configurations are disclosed that provide for increased transmitter to receiver isolation, adaptive polarization and MIMO transmission equalization. Adaptive optimization of transmission parameters based upon side information provided in the form of metric feedback from a far end receiver utilizing the antenna system is also disclosed.

Abstract: A transmitter modulator that is operable to modulate signals according to multiple modulation formats includes a first modulator, a second modulator, and a polarization beam combiner. The first modulator encodes a first signal according to a first modulation format. The second modulator encodes a second signal according to a second modulation format, the first signal orthogonally polarized with respect to the second signal. The polarization beam combiner combines the first signal and the second signal for transmission.

Abstract: A MIMO wireless communications device supports a dual polarized mode of antenna operation and a single polarized mode of antenna operation. Antenna mode selection is performed as a function of signal to noise ration information and/or rank information corresponding to a communications channel matrix. One of a communications device's processing chains is switched between first and second polarization orientation antennas, e.g., vertical and horizontally polarized antennas, as a function of the antenna mode selection. In various embodiments, the dual polarized mode is advantageously used for high SNR users, while in the low SNR regime, where the capacity is limited by received power, the single polarized antenna configuration, sometimes referred to as the spatial MIMO configuration, is used.

Abstract: A method of radiating a radioelectric signal in an area of interest composed of at least two different area sectors, the method including providing at least two sector antennas arranged respective feed signals obtained from said signal; spacing apart the at least two sector antennas from each other of a distance equal to or greater than one wavelength of a radioelectric signal to be irradiated; and acting on the feed signals fed to the at least two sector antennas in such a way that a relative phase of signals transmitted by the at least two sector antennas is caused to vary in time.

Abstract: A directional antenna is disclosed. The directional antenna may include a support structure for defining a support surface; a first antenna stack positioned on the support surface, the first antenna stack having multiple antenna elements oriented in a first orientation, allowing the first antenna stack to concentrate radiations in a first direction; a second antenna stack positioned on the support surface, the second antenna stack having multiple antenna elements oriented in a second orientation, the second orientation being rotated a predetermined angle with respect to the first orientation, allowing the second antenna stack to concentrate radiations in a second direction different from the first direction; and a controller configured to selectively activate at least one of the first antenna stack or the second antenna stack to steer the radiations of the directional antenna in different directions without physical/mechanical movement of the antenna stacks.

Abstract: Provided is a radio communication system using CO-Channel (CO-CH) to improve a reception quality at low cost. The radio communication system includes: a transmitter that transmits a first polarized signal and a second polarized signal to a receiver and terminates the transmission of the second polarized signal in accordance with an instruction from the receiver; and the receiver that receives the polarized signal from the transmitter, determines whether or not a reception quality of the second polarized signal becomes lower than a threshold value, and issues an instruction to the transmitter to terminate transmission of the second polarized signal to the transmitter when the reception quality becomes less than the threshold value.

Abstract: Provided is a device for tracking polarizations. A receiving polarization tracking device includes a feeder for finding vertical and horizontal vector components by receiving vertical and horizontal polarizations, a polarization estimator for estimating distortion of polarizations using the vertical and horizontal vector components outputted from the feeder, a polarization controller for controlling amplitudes and phases of vertical and horizontal polarizations based on information about the estimated distortion from the polarization estimator and an output signal from the receiving polarization tracking device, and a combiner for combining the vertical and horizontal polarizations controlled from the polarization controller.

Abstract: A diversity antenna system with electrical tilt has two dual polarized, tilt adjustable antenna stacks (44A) and (44B) with physical separation providing space diversity. Each antenna stack (44A) or (44B) has two polarizations associated with independently adjustable electrical tilt angles. The electrical tilt angles of each antenna stack (44A) or (44B) are controlled to be equal to those of the other antenna stack to provide co-polarization or anti-polarization tilt coupling. The antenna system (40) may operate with multiple carrier frequencies each associated with a respective pair of polarizations of different antenna stacks (44A) and (44B) with co-polarization or anti-polarization tilt coupling. Antenna tilt angles are controllable so that different carrier frequencies are associated with independently adjustable angles of electrical tilt. The system may be used with groups of both contiguous and non-contiguous carrier frequencies.

Abstract: An antenna system includes: an orthogonal multi-polarization antenna configured to output independent double orthogonal polarizations through two independent input/output terminals; an antenna main control unit configured to perform a polarization control algorithm, collect and analyze information for polarization control, and provide polarization control information; and a polarization control unit configured to perform independent amplitude and phase control with regard to a pair of independent channels connected to the orthogonal multi-polarization antenna, based on the polarization control information received from the antenna main control unit, so that various polarizations are formed.

Abstract: Systems and methods for increasing communications bandwidth using non-orthogonal polarizations are provided herein. Under one aspect, a method of transmitting M independent signals, where M is at least 3, includes receiving the M signals from respective sources; at a transmitter polarization module, obtaining first and second linear combinations of the M signals; providing the first and second linear combinations to first and second input ports of a transmitter antenna; and transmitting with the transmitter antenna the first linear combination at a first polarization and the second linear combination at a second polarization orthogonal to the first polarization. The method may further include receiving at a receiver antenna the first linear combination at the first polarization, and the second linear combination at the second polarization; obtaining at receiver circuitry the M signals based on the received first and second linear combinations; and outputting the M signals on respective output ports.

Abstract: A mobile transceiver uses position and/or orientation knowledge to increase the capacity of a wireless link by transmitting over multiple electromagnetic polarizations. Sensors may include accelerometers, compasses, position sensors such as GPS receivers, and other means of determining the relative orientation of a mobile tranceiver to its base station. This information is used to properly shape transmitted signals and correlate received signals to increase the link capacity of the wireless link, either through channel multiplexing or increased link quality. This is particularly useful for mobile phones used on cellular networks utilizing high data volume on the allocated spectrum.

Abstract: A wireless communication system can include polarization agile antennas to enable adaptation to the polarization characteristics of a changing propagation channel. In one embodiment, a mobile terminal can include one or more polarization-agile antennas, and can select polarization orientations that are preferentially propagated through the changing propagation channel. In another embodiment, a mobile terminal having two polarization-agile antennas can provide spatial diversity, polarization diversity, or combinations of both. Multiple-input multiple-output (MIMO) systems can include polarization-agile antennas to allow for switching between spatial and polarization diversity, combined spatial and polarization diversity, and various Eigen channel decompositions using spatial, polarization, and combined spatial and polarization dimensions. An extended polar normalization provides enhanced fidelity for methods of communications system modeling.

Abstract: Systems and methods can provide alternatives to a global positioning system (GPS). For example, certain systems can operate on 1090 MHz and provide for methods of estimating location that can be used in place of GPS. Thus, a method can include obtaining an estimate of position of an own aircraft based on time of arrival of signals from a plurality of ground stations. The calculation of the estimate can be performed in the own aircraft. The method can also include using the estimate of position instead of a position from a global positioning system.