Abstract: An antenna array and method for a multi-user multi-input multi-output antenna array system including at least two receive antennas at a receive area, where the receive antennas are spaced from each other on the order of symbol wavelengths, at least two transmit antennas at a transmit area with at least one transmit antenna spaced from the other at least two transmit antennas on the order of symbol wavelengths, and wherein the antenna array is optimized for multi-user performance for rural areas.

Abstract: A cable for distributed fiber optic sensing comprising a flexible tape, an optical fiber suitable for Brillouin scattering measurement forming at least two lengths, and at least one free end of at least one length being connectable to a reading unit, wherein at least a section of the longitudinal length of the flexible tape is situated between at least a section of the two lengths such that the two lengths are in close proximity such that a temperature gradient between the two lengths is minimized, and wherein the section of the tape and the section of lengths can flex together.

Abstract: A cable for distributed fibre optic sensing comprising a flexible tape, an optical fibre suitable for Brillouin scattering measurement forming at least two lengths, and at least one free end of at least one length being connectable to a reading unit, wherein at least a section of the longitudinal length of the flexible tape is situated between at least a section of the two lengths such that the two lengths are in close proximity such that a temperature gradient between the two lengths is minimized, and wherein the section of the tape and the section of lengths can flex together.

Abstract: A magnet array is disclosed which is suitable for inter alia producing a remote field for use in unilateral magnetic resonance. In the “Magnet Array”, two separated magnets, which are magnetized along a substantially same collinear magnetization direction, produce a field with a local maximum centered above and between them. The field produced by the two separated magnets is substantially parallel to the collinear magnetization direction of the two separated magnets. A third magnet is centered between the two separated magnets. The third magnet has a magnetization direction which is substantially parallel to the collinear magnetization direction of the two separated magnets. The third magnet produces a field which is substantially parallel to the collinear magnetization direction of the two separated magnets, and adds to the increasing field below the local maximum point produced by the two separated magnets.

Abstract: A unilateral NMR sensor comprising a ferromagnetic yoke; a permanent magnet arranged on the yoke; a pole piece on the magnet; the pole piece including an air-pole piece interface surface whose shape corresponds to an equipotential contour of magnetic scalar potential. An approach for designing single-sided magnets suitable for unilateral magnetic resonance (UMR) measurements is presented. The method uses metal pole pieces to shape the field from permanent magnets in a target region. The pole pieces are shaped according to solutions to Laplace's equation, and can be designed using a combination of analytical methods and numerical optimization. The design leads to analytical expressions for the pole piece shape and magnetic field. The method is developed in Cartesian, polar, and spherical coordinates, and the merits of each system are discussed. The effects of finite magnet size on the field quality are explored through simulation, and are found to have a substantial effect in many cases.

Abstract: A unilateral NMR sensor comprising a ferromagnetic yoke; a permanent magnet arranged on the yoke; a pole piece on the magnet; the pole piece including an air-pole piece interface surface whose shape corresponds to an equipotential contour of magnetic scalar potential. An approach for designing single-sided magnets suitable for unilateral magnetic resonance (UMR) measurements is presented. The method uses metal pole pieces to shape the field from permanent magnets in a target region. The pole pieces are shaped according to solutions to Laplace's equation, and can be designed using a combination of analytical methods and numerical optimization. The design leads to analytical expressions for the pole piece shape and magnetic field. The method is developed in Cartesian, polar, and spherical coordinates, and the merits of each system are discussed. The effects of finite magnet size on the field quality are explored through simulation, and are found to have a substantial effect in many cases.

Abstract: A cable for distributed fibre optic sensing comprising a flexible tape, an optical fibre suitable for Brillouin scattering measurement forming at least two lengths, and at least one free end of at least one length being connectable to a reading unit, wherein at least a section of the longitudinal length of the flexible tape is situated between at least a section of the two lengths such that the two lengths are in close proximity such that a temperature gradient between the two lengths is minimized, and wherein the section of the tape and the section of lengths can flex together.

Abstract: A magnet array is disclosed which is suitable for inter alia producing a remote field for use in unilateral magnetic resonance. In the “Magnet Array”, two separated magnets, which are magnetized along a substantially same collinear magnetization direction, produce a field with a local maximum centered above and between them. The field produced by the two separated magnets is substantially parallel to the collinear magnetization direction of the two separated magnets. A third magnet is centered between the two separated magnets. The third magnet has a magnetization direction which is substantially parallel to the collinear magnetization direction of the two separated magnets. The third magnet produces a field which is substantially parallel to the collinear magnetization direction of the two separated magnets, and adds to the increasing field below the local maximum point produced by the two separated magnets.

Abstract: A unilateral NMR sensor comprising a ferromagnetic yoke; a permanent magnet arranged on the yoke; a pole piece on the magnet; the pole piece including an air-pole piece interface surface whose shape corresponds to an equipotential contour of magnetic scalar potential.

Abstract: A Brillouin Optical Time-Domain Analysis (BOTDA) distributed sensor system and method use a continuous wave (cw) Stokes wave interrupted with a dark pulse for improved spatial resolution. The cw Stokes wave causes a continuous depletion of the pump wave. The dark pulse causes the depletion to stop for the duration of the pulse. Brillouin interactions are measured during the dark pulse. Very narrow dark pulses can be used because sufficient Stokes wave energy is maintained. The system produces a stronger time-domain signal and narrower linewidth Brillouin spectra than traditional techniques using a bright Stokes pulse. Narrower measurement pulses can be used leading to improved spatial resolution. A quasi-cw Stokes wave can be used to reduce the effect of stimulated Brillouin scattering (SBS) in long measurement fibers. The system can be used for distributed strain or temperature measurements.

Abstract: A distributed fiber optic sensor simultaneously interrogates the sensing fiber with two counter propagating light beams. One beam is set to a constant frequency. The second beam is modified to contain a “comb” of frequencies, with each frequency component in the comb offset by a predetermined amount. Each of the frequency components in the comb, herein referred to as teeth, is able to interact with the counter-propagating beam through the Brillouin scattering process. With proper selection of the comb characteristics such as the number of teeth, the frequency spacing of teeth, the spectral width of teeth, and the relative amplitude of the teeth, a representation of the Brillouin spectrum at each point in the fiber can be obtained simultaneously with a single pass through the fiber.

Abstract: A unilateral NMR sensor comprising a ferromagnetic yoke; a permanent magnet arranged on the yoke; a pole piece on the magnet; the pole piece including an air-pole piece interface surface whose shape corresponds to an equipotential contour of magnetic scalar potential

Abstract: A Brillouin Optical Time-Domain Analysis (BOTDA) distributed sensor system and method use a continuous wave (cw) Stokes wave interrupted with a dark pulse for improved spatial resolution. The cw Stokes wave causes a continuous depletion of the pump wave. The dark pulse causes the depletion to stop for the duration of the pulse. Brillouin interactions are measured during the dark pulse. Very narrow dark pulses can be used because sufficient Stokes wave energy is maintained. The system produces a stronger time-domain signal and narrower linewidth Brillouin spectra than traditional techniques using a bright Stokes pulse. Narrower measurement pulses can be used leading to improved spatial resolution. A quasi-cw Stokes wave can be used to reduce the effect of stimulated Brillouin scattering (SBS) in long measurement fibers. The system can be used for distributed strain or temperature measurements.

Abstract: An array of induction magnetometers for use in airborne transient electromagnetic (ATEM) geophysical exploration is disclosed, having similar weight and external dimensions of prior art induction magnetometers but with improved signal strength, signal-to-noise ratio, higher frequency, self-resonance and bandwidth, and providing accurate and well monitored calibration.