546 results about "Transverse magnetic" patented technology

A method and tool using a continuous electromagnetic wave from a transverse magnetic-dipole source with a coaxial electric-dipole receiver is described for the detection of external sidewall cracks and other anomalies in boiler tubes and other enclosures. The invention utilizes the concept of radar backscatter rather than eddy-currents or ultrasound, which are sometimes used in prior art crack-detection methods. A numerical study of the distribution of the fields shows that the direct transmission from the source to the receiver is reduced from that in free space. Further, if the diameter of the receiver dipole is made sufficiently small, it should be possible to detect cracks with a scattering loss of up to -40 dB in thin-walled boiler tubes.

Systems and methods for monitoring a subsurface formation property and for placing a borehole in the vicinity of a well in the formation. A slotted tubular is utilized to provide through-tubular signal transmission and/or reception using an antenna adapted to generate a magnetic dipole moment with a transverse or controllable orientation. Hydraulic isolation between the interior and exterior of the tubular at the slot is provided by a pressure barrier. The tubular also forms part of a system for accurately placing a well within a desired distance and orientation relative to an existing well.

Method and system for subsurface logging utilizing a modified metallic tubular having an elongated body with tubular walls and a central bore adapted to receive a support member. The tubular including slotted stations to provide through-tubular signal transmission and/or reception. Pressure barrier means provide hydraulic isolation at the slotted stations. The support member is equipped with various sources and sensors, including an antenna adapted to generate a magnetic dipole moment with a transverse or controllable orientation, and adapted for engagement within the tubular. The apparatus is suitable for LWT, LWD, and TLC logging operations.

The invention discloses a polarization rotator based on an asymmetric vertical slot waveguide, which comprises an incident end waveguide used for leading in external incident light, a mode conversion waveguide used for converting TE/TM (Transverse Electric/Transverse Magnetic) mode incident light into TM/TE (Transverse Magnetic/Transverse Electric) mode emergent light, and an emergent end waveguide used for leading out a TM/TE mode, wherein the incident end waveguide, the mode conversion waveguide and the emergent end waveguide are asymmetric slot waveguides. With the adoption of the structure, the symmetry of a material is broken longitudinally, and the symmetry of a geometrical dimension is broken transversely, so that intrinsic modes of specific waveguides are mixed modes; the two intrinsic mixed modes can be converted mutually; and mutual conversion between a TE mode and a TM mode can be achieved finally. The polarization rotator can convert a TE/TM mode into the TM/TE mode by once etching, so that the manufacturing difficulty of a device is reduced greatly.

Methods and apparatus are disclosed for minimizing or eliminating an undesired axial electric current induced along a subsurface borehole in the process of subsurface measurements with transmitter and/or receiver antennas which are substantially time varying magnetic dipoles with their dipole moments aligned at an angle to the axis of the borehole. Some antennas are disposed within the borehole on instruments having a non-conductive support member. One instrument includes a conductive all-metal body with an antenna adapted for induction frequencies. Antenna shields adapted for controlled current flow are also provided with an all-metal instrument. Methods include providing an alternate path for the current along the instrument body. Another method includes emitting a controlled current to counter the undesired current. Another method corrects for the effect of the current using a superposition technique. An embodiment of the instrument includes an antenna disposed between a pair of electrically coupled electrodes. The antenna is disposed on the instrument such that it comprises a tilted or transverse magnetic dipole. Another embodiment of the instrument includes a non-conductive housing with a conductive segment disposed thereon. An antenna is disposed on the instrument about the conductive segment. Another embodiment includes an antenna disposed between two pairs of electrodes with means to measure a voltage at the electrodes when electromagnetic energy is transmitted within the borehole. Yet another instrument includes an antenna disposed between a first pair of electrodes and means to measure a voltage at the electrodes when electromagnetic energy is transmitted within the borehole. This embodiment also includes means to energize a second electrode pair in response to the voltage measured at the first electrode pair.

A new technique for maintaining the alignment of electric and magnetic fields in an x-ray tube so the tube can be operated in the presence of a static external magnetic field without being negatively affected thereby. Deflection of the electron beam of the x-ray tube by the high magnetic field is reduced or eliminated by modifying or canceling, at a location near the electron beam, the magnetic field components transverse to the beam. In a preferred embodiment, a set of electromagnet coils are positioned on or near the tube and oriented in a way that when current is applied internal magnetic fields are produced in a direction opposite to the transverse magnetic fields, thereby causing cancellation. In one implementation, one or more sensors are used to detect the transverse magnetic fields. The sensor is positioned near the electron beam, either inside or outside the x-ray tube. The sensor produces a signal dependent on a static magnetic field component transverse to the desired direction of the electron beam. This signal is used to control the amount of current applied to the coils. A controller and a feedback circuit may be included to adjust in real time the amount of current being applied.

An improved low-angle radiation antenna is obtained through excitation of a tangential electric field on the high-impedance surface, as well as leaky transverse-electric surface waves. Such fields and surface waves cannot normally occur on an ordinary metal surface. The tangential electric field on the high-impedance region excites a transverse-magnetic surface wave on a surrounding metal surface which gives improved low-angle radiation in the E-plane of an antenna disposed on the high impedance surface. Leaky transverse-electric surface waves provide improved radiation in the H-plane of the antenna.

A hybrid synchronous electric machine driven by the transverse magnetic flux has a rotor and a stator, the rotor armature has a massive cogged iron rings (12) in close vicinity of active parts of the motor, and cogged iron rings (14, 15) as component parts of the rotor are provided with cross-cut insulating gaps. Eddy current losses are low because eddy currents in cogged iron rings are impeded by cross-cut insulating gaps therein. Eddy currents in all passive parts of the motor (rotor armature (11), stator armature (1), ball bearing (9) and the like) are negligible since the current induced in the copper ring (12) neutralizes all the dissipated magnetic flux outside the active area of the motor. A hybrid synchronous electric machine which has low eddy current losses and high energy efficiency can be realized.

A high speed, highly sensitive optical sensing platform and a method for detecting and/or measuring characteristics of a substance in a measurement sample are disclosed. The platform includes at least one pair of optical paths formed in a waveguide, a light source for injecting optical beams along the optical paths, a light modulator for enabling the excitement of a transverse electric and a transverse magnetic guide modes, and a phase detector for detecting phase differences between the beams propagating along the optical paths. One of the optical paths has a target analyte of unknown concentration with a measurement sample bound to its upper surface, while the second optical path has a reference sample containing a known concentration of the target analyte bound to its upper surface. A guided mode modulator causes an optical beam to propagate through the waveguide sequentially as two polarized modes. The highly sensitive platform is especially useful for directly detecting and/or measuring very small numbers of small molecules, bio-molecules, microorganisms in a liquid or gaseous test sample.

The invention relates to a pressure sealing device and a method for decreasing the cut-off frequency in such a pressure sealing device used in a radar level gauging system for gauging a filling level of a product kept in a container, the sealing device comprises a waveguide for feeding microwaves in at least one of the following mode types: transverse electric mode, transverse magnetic mode or hybrid mode. Said waveguide is sealed by a dielectric material. A center conductor is arranged at least partially within said dielectric material.

The invention provides a polarization beam splitter rotator and a design method thereof. The polarization beam splitter includes a double-layer trapezoidal mode converter and a reverse tapered coupler which are connected in series; the double-layer trapezoidal mode converter converts a transverse magnetic wave zero-order mode into a transverse electric wave first-order mode, and the reverse tapered coupler converts the transverse electric wave first-order mode into a transverse electric wave zero-order mode. The width of a first trapezoidal waveguide and a second trapezoidal waveguide is selected, and according to a relation between waveguide length and mode conversion efficiency, the length of the first trapezoidal waveguide and the second trapezoidal waveguide is determined; and the width of a third trapezoidal waveguide and a fourth trapezoidal waveguide is selected, and according to a relation between the waveguide length and mode conversion loss, the length of the reverse tapered coupler is determined. Characteristics of large working bandwidth, high conversion efficiency and high manufacturing tolerance and the like are realized through parameter optimization, the polarization beam splitter rotator can be used for improving practicability of a single-fiber three-way multiplexer, in addition, a manufacturing method is simple, is compatible with a standard silicon photon processing technological process, and the polarization beam splitter rotator and the design method thereof have relatively high practical value and good application prospects.

An apparatus and process are provided for controlling the cross sectional temperature profile of a continuously moving workpiece with an induction coil assembly that provides for a combination of longitudinal and transverse magnetic flux field heating of the workpiece. The induction coil assembly includes means for laterally moving the workpiece in and out of the coil assembly without movement of the coil assembly.

A grating coupled surface plasmon resonance optical modulator is disclosed. A electro-optic polymer dielectric is deposited on the metallic surface of a diffraction grating to provide a metal/dielectric interface. A surface plasmon will propagate at the metal/dielectric interface in a resonant condition, e.g., when the metal surface is illuminated by transverse magnetic (TM) polarized light of the appropriate wavelength, angle of incidence and phase velocity. In the present invention, phase velocity is controlled by the diffraction grating. A transparent electrode deposited on the electro-optic layer allows an electrical potential to be applied across the electro-optic polymer. The applied electrical potential (voltage) changes the index of refraction of the electro-optic polymer, thereby disrupting the resonant condition to produce an optically detectable change in reflectance of incident light from the metal layer. The disclosed grating coupled surface plasmon resonance optical modulator may be configured as an electronically or optically addressable array.

A method of analysing electromagnetic survey data from an area of seafloor (6) that is thought or known to contain a conductive or resistive body, such as a subterranean hydrocarbon reservoir (12), is described. The method includes providing electric field data and magnetic field data, for example magnetic flux density, obtained by at least one receiver (25) from a horizontal electric dipole (HED) transmitter (22) and determining a vertical gradient in the electric field data. The vertical gradient in the electric field data and the magnetic field data are then combined to generate combined response data. The combined response data is compared with background data specific to the area being surveyed to obtain difference data sensitive to the presence of a subterranean hydrocarbon reservoir. Because the combined response data are relatively insensitive to the transverse electric (TE) mode component of the transmitted signal, the method allows hydrocarbon reservoirs to be detected in shallow water where the TE mode component interacting with the air would otherwise dominate. Furthermore, because there is no mixing between the TE and transverse magnetic (TM) modes in the combined response data, data from all possible transmitter and receiver orientations may be used. The background data may be provided by magneto-telluric surveying, controlled source electromagnetic surveying or from direct geophysical measurement.

The invention discloses a TM (Transverse Magnetic) mode dielectric filter. The TM mode dielectric filter comprises a plurality of filter units, each of the filter units consists of an elastic connecting mechanism, a dielectric resonator and a resonance cavity, wherein the elastic connecting mechanism comprises an elastic component and an upper cover; the columnar dielectric resonator is arranged in the resonance cavity, the upper end surface of the dielectric resonator is connected with the elastic component, and the lower end surface of the dielectric resonator is connected with the bottom of the inner cavity of the resonance cavity; the resonance cavity comprises one or more than one cavity, and a coupling window is formed on the cavity; and the upper cover is covered on the resonance cavity. Therefore, the TM mode dielectric filter provided by the invention has the advantages of excellent electrical function, application ability and high reliability.

The invention discloses a multi-channel integrating light guide mode multiplexing-demultiplexing device. The multi-channel integrating light guide mode multiplexing-demultiplexing device comprises (N+1) input monomode optical waveguides (N is greater than 0), wherein the tail end of the zero input light guide is successively connected with a first cone light guide, a first multimode optical waveguide, an nth cone light guide, an nth multimode optical waveguide,......, the nth cone light guide, the nth multimode optical waveguide, and an output multimode optical waveguide as well as an nth input waveguide, n=1,......, N, each input light guide tail end is successively respectively connected with a S-shaped winding light guide, a coupled zone light guide and the other S-shaped winding light guide structure; and the nth high-order mode of the nth multimode optical waveguide is a transverse electric mode or a transverse magnetic mode, and n=1,......, N. The multi-channel integrating light guide mode multiplexing-demultiplexing device provided by the invention can respectively load multi-path signals on N eigen modes of the same multimode waveguide, the model multiplexing is formed, and the large capacity data transmission is realized; and the multi-channel integrating light guide mode multiplexing-demultiplexing device is suitable for a key function device of a dual-polarization mode multiplexing system, the design is convenient, the structure is compact, and the expansion is convenient.