3753 results about "Microwave signals" patented technology

A motion detector based on the Doppler principle contains a microwave module for emitting a microwave signal containing at least two frequencies into a room under surveillance and for receiving the radiation reflected from the latter. An evaluation stage is connected to the microwave module and generates first and second Doppler signals from the received radiation. The first and second Doppler signals have a phase difference which is proportional to the distance of an object reflecting the microwave signal. The phase difference is determined by an integral transformation. In addition, the relative size of an object and the direction of travel of an object reflecting the microwave signal can be determined by the evaluation stage.

Systems and methods for detecting a respiration signal in a target area are disclosed. Briefly described, in architecture, one embodiment of the system, among others, can be implemented as follows. The system includes a scanning antenna configured to transmit a microwave signal across a horizontal axis in the target area. Also, the system includes a control system that tracks the position of the scanning antenna along the horizontal axis. A signal processing system then detects a respiration signal of a living subject in the target area from reflected microwave signals from the target area and the positional data. Other systems and methods are also provided.

A microstrip antenna has feed element 102 and parasitic elements 104, 106 on the front surface of substrate 1. Microwave electrical power is applied to feed element 102. Parasitic elements 104, 106 are connected via through hole type leads passing through substrate 1, to switches upon the rear surface of substrate 1, respectively. By actuating the switches individually, parasitic elements 104, 106 are individually switched between a grounded state and a float state. The direction of the radio beam emitted from the microstrip antenna is varied by selecting which of parasitic elements 104, 106 is grounded and floated. A microwave signal source connects to feed element 102 via an feed line 108 very much shorter than the wavelength, accordingly the transmission losses being low and the efficiency being excellent.

Microwave examination of individuals is carried out by transmitting microwave signals from multiple antenna locations into an individual and receiving the backscattered microwave signals at multiple antenna locations to provide received signals from the antennas. The received signals are processed to remove the skin interface reflection component of the signal and the corrected signal data are provided to a hypothesis testing process. In hypothesis testing for detecting tumors, image data are formed from the test statistic used to perform a binary hypothesis test at each voxel. The null hypothesis asserts that no tumor is present at a candidate voxel location. The voxel threshold is determined by specifying a false discovery rate to control the expected proportion of false positives in the image. When the test statistic value associated with a voxel is greater than the threshold, the null hypothesis is rejected and the test statistic is assigned to the voxel. For voxels where the test statistic falls below the threshold, the null hypothesis is accepted and the voxel value is set to zero. The resulting image indicates the locations or other characteristics of detected tumors.

System and methods are disclosed for fluid measurements which may be utilized to determine mass flow rates such as instantaneous mass flow of a fluid stream. In a preferred embodiment, the present invention may be utilized to compare an input mass flow to an output mass flow of a drilling fluid circulation stream. In one embodiment, a fluid flow rate is determined by utilizing a microwave detector in combination with an acoustic sensor. The acoustic signal is utilized to eliminate 2 pi phase ambiguities in a reflected microwave signal. In another embodiment, a fluid flow rate may be determined by detecting a phase shift of an acoustic signal across two different predetermined transmission paths. A fluid density may be determined by detecting a calibrated phase shift of an acoustic signal through the fluid. In another embodiment, a second acoustic signal may be transmitted through the fluid to define a particular 2pi phase range which defines the phase shift. The present invention may comprise multiple transmitters/receivers operating at different frequencies to measure instantaneous fuel levels of cryogenic fuels within containers positioned in zero or near zero gravity environments. In one embodiment, a moveable flexible collar of transmitter/receivers may be utilized to determine inhomogenuities within solid rocket fuel tubes.

Apparatus and methods are disclosed for detecting anomalies in microwave penetrable material that may be used for locating plastic mines or pipes underneath the ground. A transmitter is positioned at a plurality of different positions above the ground. A microwave signal is transmitted that is stepped over a plurality of frequencies. At each position, a plurality of reflections are received corresponding to each of the plurality of frequencies that were transmitted. A complex target vector may be produced at each position that contains complex values corresponding to magnitude, phase, and time delay for each of the plurality of reflections received at that location. A complex reference data vector may be produced, either based on predetermined values or based on data from the received plurality of reflections. A comparison is made between the complex target vector and the complex reference data vector to produce a channel vector. In one embodiment, an operator may be applied to the channel vector such as a complex filter matrix or to add a complex conjugate. A response signal is produced and anomalies are detected by variations in the response signal with respect to the plurality of positions.

The invention discloses a COTDR (coherent detection based optical time-domain reflectometry) fused long-distance coherent detection brilouin optical time-domain analyzer which comprises a narrow-linewidth laser, two couplings, a microwave signal source, an electro-optic modulator, an isolator, a long-distance sensing optical fiber, an optical circulator, a 3 db coupling, a pulse modulator, an Er-doped fiber amplifier, a scrambler, a pulse signal generator, a balancing photoelectric detector, an electrical frequency spectrum analyzer, a data processing module and an acousto-optic modulator. According to the invention, the signal-to-noise ratio of BOTDA (brilouin optical time domain analysis) is improved by using a coherent detection method, a non-local effect of a BOTDA system is reduced in a double-sideband detection mode, and the sensing distance is more than 70 km under the condition of no light amplification such as raman; and according to the invention, the COTDR is fused to a coherent detection based BOTDA system, and the system can run in a breakpoint testing mode, so that the defect that the traditional BOTDA can not run when a sensing fiber has breakpoints and can not carry out positioning on breakpoints is effectively overcome, thereby enhancing the adaptability and practicability of the sensing system.

The invention discloses a microwave power detection system based on parallel-connected MEMS (micro-electromechanical system) cantilever beams and a preparation method of the microwave power detection system. The method is used for on-line measurement, electrostatic force can be generated between each MEMS cantilever beam and a transmission line in a center signal line transmission process, the cantilever beams are pulled downwards, and an interval between each cantilever beam and a corresponding test electrode becomes smaller, so that capacitance values are changed and microwave power in one-to-one correspondence with the capacitance values is obtained by measuring the changed capacitance values. The microwave power detection system based on the parallel-connected MEMS cantilever beams comprises a gallium arsenide substrate, wherein a plane-waveguide center signal line (A), a parallel-connected MEMS cantilever beam structure (B) and a capacitance type microwave power sensor (C) are arranged on the substrate. When a microwave signal is transmitted on the plane-waveguide center signal line, the two parallel-connected MEMS cantilever beams generate displacement under the action of the electrostatic force, and the to-be-measured power is detected by the capacitance type microwave power sensor.

The invention discloses a device and a method for phase detection based on a direct type micromechanical microwave power sensor. The device comprises an adjustable digital phase shifter (12), a power combiner (16), the direct type micromechanical microwave power sensor (19) and a digital multimeter (20), a reference microwave signal Vref is connected with a first input port (14) of the power combiner, a to-be-detected signal Vx is connected with an input port (11) of the adjustable digital phase shifter, an output port (13) of the adjustable digital phase shifter is connected with a second input port (15) of the power combiner, an output port (17) of the power combiner is connected with an input port (18) of the direct type micromechanical microwave power sensor, and back holes (8) on the direct type micromechanical microwave power sensor (19) are connected with the digital multimeter (20). The objective of accurate detection of microwave signal phase position is realized by utilizing the method of power after combining a measuring reference signal with the to-be-detected signal after phase shifting by the adjustable digital phase shifter.

The invention discloses a micromechanical silicon-based clamped beam-based phase detector and a detection method. The phase detector comprises a silicon substrate (1), a source (2), a drain (3), a first clamped beam-anchoring area (61), a second clamped beam-anchoring area (62), a grid (5) and a clamped beam (7), wherein the source (2) and the drain (3) are grown on the surface of the silicon substrate (1) and used for outputting saturation current, the source (2) is arranged opposite from the drain (3), and the clamped beam (7) is arranged upon the grid (5) and is opposite to the grid (5). The detection method includes the following steps: when a direct-current offset is loaded on a first pull-down electrode (81) and a second pull-down electrode (82) and the clamped beam (7) is pulled down and is in contact with the grid (5), two microwave signals which have the same frequency and certain phase difference are simultaneously loaded on the grid (5); the saturation current of the drain (3) is processed, so that high-frequency signals are filtered, and therefore the current signal of phase difference information is obtained. The structure of the phase detector is simple, and measurement is easy.

The invention relates to a BOTDR (Brillouin Optical Time Domain Reflectometer) for calibrating optical power of reference light and a calibrating method thereof. The calibrating method comprises the following steps of: acquiring an electric signal of local reference light from a heterodyne photoreceiver on a basis of a traditional BOTDR for heterodyne coherent detection; transmitting the electric signal subjected to analog-to-digital conversion in a computer to be used as the optical power calibrating feedback quantity of the reference light; sending out an instruction by the computer to adjust the output power of a microwave source and change the optical power of the local reference light so that the difference between the optical power of the local reference light and the preset reference light power is smaller than a set value; calibrating the power; and detecting a BOTD signal. In the invention, the BOTDR in a working process can not be influenced by the working environment temperature, a microwave transmission line connecting the microwave source with an electro-optic modulator and different power responses of the electro-optic modulator on microwave signals of different frequencies, the error between the reference light power at different frequency points and the preset power is smaller than a set value, and the accurate measurement of the stress and the temperature is ensured.

A method and a system for radar-based gauging of a filling level of a filling material is disclosed, wherein the tank has at least one interfering structure. The method comprises: transmitting at a first time moment a microwave signal towards the surface of the filling material; receiving microwave signals as reflected against the surface of the filling material and as reflected against said at least one interfering structure; calculating based on propagation times of the transmitted and reflected microwave signals at least two distances to reflective surfaces in the tank; and repeating at a second time moment the transmitting, the detecting and the calculating, wherein said first time moment is timely separated from said second time moment. Based on the several repeated measurements, the distance to the surface of the filling material is determiend as the calculated distance that exhibits the greatest change between said first and second time moments. Based on this time difference analysis, it is possible to discinguish moving surfaces very easy and acurate. The method is specifically advantageous in overfill or high level alarm systems.

A wind turbine blade inspection system includes a frequency modulated continuous wave radar system configured to be movable with respect to a wind turbine blade while transmitting reference microwave signals and receiving reflected microwave signals and a processor configured for using a synthetic aperture analysis technique to obtain a focused image of at least a region of the wind turbine blade based on the reflected microwave signals.

A microwave heating apparatus is designed to improve distribution of the microwaves introduced into a multi-mode microwave cavity for heating or other selected applications. The microwave heating apparatus includes a microwave signal generator and a waveguide to convey microwave power to the cavity. A perforated metal plate disposed within the cavity encloses a volume adjacent to the waveguide opening, forming a leaky multimode subcavity. Through multiple processes of reflection, transmission, diffraction, and scattering, the leaky subcavity serves to smooth the microwave power distribution in the near-field region adjacent to the waveguide to better disperse the energy throughout the main applicator cavity. A more uniform level of microwave power is thereby applied to the workpiece.

A delay filter uses the dielectric mono-block triple-mode resonator and unique inter-resonator coupling structure, having smaller volume and higher power handling capacity. The triple-mode mono-block resonator has three resonators in one block. An input/output probe is connected to each metal plated dielectric block to transmit microwave signals. Corner cuts couple a mode oriented in one direction to a mode oriented in a second, mutually orthogonal direction. An aperture between two blocks couples all six resonant modes, and generates two inductive couplings by magnetic fields between two modes, and one capacitive coupling by electric fields. The input/output probes, coupling corner cuts and aperture are aligned such that all six resonators are coupled in the desired value and sign, so constant delay on the transmitted signal within certain bandwidth can be achieved. By connecting the input and output probes to the base printed circuit board, the delay filter is surface mountable.

The invention relates to a road measuring method, a device and a non-stop charging system. The method comprises the following steps: adopting a microwave transaction module for carrying out information interaction with on-vehicle microwave equipment running on a road to be measured; adopting a plurality of microwave positioning modules for simultaneously intercepting and capturing the microwave signals sent by the on-vehicle microwave equipment to the microwave transaction module; using each microwave positioning module for calculation to generate the respectively obtained microwave signal intensity data; determining the position of the on-vehicle microwave equipment in the road to be measured according to each generated microwave detection signal intensity datum; determining the distancefrom the on-vehicle microwave equipment to the microwave transaction module according to the position of the on-vehicle microwave equipment in the road to be measured; and determining whether the information interaction between the current microwave transaction module and the on-vehicle microwave equipment can be continued or not according to the distance from the on-vehicle microwave equipment to the microwave transaction module. The invention aims at solving the problems of signal interference and lack when the on-vehicle microwave equipment in an electronic charging system is positioned inthe edge of a communication region, and solving the problem of low accuracy of the pike charging caused by signal interference and lack.

The invention discloses a microwave power source and a microwave ablation therapeutic instrument, which relate to a full-solid-state microwave power generating circuit and a microwave therapeutic instrument circuit. The microwave power source adopts a full-solid-state circuit close-loop control to achieve stable microwave power output and continuous adjustable microwave power. The microwave energy can generate enough penetration depth in human tissue to enlarge the ablation range. The ablation range of 915 MHz microwave frequency band is larger than that of 2,450 MHz microwave frequency band, so that the 915 MHz microwave frequency band is more suitable for ablation therapy. The microwave power source comprises a microwave signal generator, a power control time adjusting circuit, an impedance matcher, a drive circuit, a power splitter, a plurality of power amplifiers, a power mixer, an isolator and a power tracking and detecting circuit. The microwave ablation therapeutic instrument is constituted by the microwave power source and a microwave ablation pin under control of a microprocessor.

The present invention generally relates to the field of microwave antennas, and, more particularly, to a number of three-dimensional designs for the radiation element of an ultra-wideband monopole antenna with a symmetrical omni-directional radiation pattern operated in the frequency range between 3.1 GHz and 10.6 GHz. Said antenna is connected to the analog front-end circuitry of a wireless communication device used for transmitting and/or receiving microwave signals and meets the FCC requirements in terms of antenna gain, radiation pattern, polarization, frequency bandwidth, group delay, and size. It comprises a radiation element consisting of an air- and/or dielectric-filled cavity structure with a base plane and a radiator plane. A metallic ground plane having a relatively high surface impedance to electromagnetic waves within said frequency range, which is printed on a dielectric substrate, serves as a reflector. The monopole antenna further comprises an antenna feeding circuitry used for electronically steering the symmetrical omni-directional radiation pattern and a feeding line connecting the antenna feeding circuitry with the base plane of the radiation element. Thereby, parts of the analog front-end circuitry can optionally be placed within the air-filled part of the radiation element of the antenna. The proposed designs include a radiation element having the form of a truncated right circular cone, rotational-symmetric radiation elements with a convexly- or concavely-shaped 3D surface, respectively, a radiation element in the form of a truncated right regular pyramid with a square base plane, and radiation elements with a combined structure comprising a conical, pyramidal, convexly- or concavely-shaped first part and a closed cylindrical or cuboidal second part whose top plane is arranged on top of the congruent base plane of said first part. Further embodiments include radiation elements with the form of a radially notched cylinder or hemisphere as well as combined structures consisting of at least two convexly-shaped elements or two conical parts, respectively, stacked on top of each other.