Abstract: An antenna device for determining the filling level of a filling material in a container (tank) comprising an essentially flat array antenna with an emitting area for emitting measuring signals towards the surface of the filling material and a holder for holding the array antenna over an opening of the container and to be connected to the rim of the opening in at least two points of attachment. Further, a protective dielectric cover covers the emitting area, the dielectric cover having an extension larger than the opening in order to extend over the rim of the opening. The antenna device provides several advantages, such as a very efficient sealing of the container opening, a very clean solution towards the container and a very effective protection of the array antenna.

Abstract: A microwave sensor transmits a plurality of microwaves of different frequencies toward a detection area and carries out an object detection operation based on reflected waves of the microwaves from an object present in the detection area. The microwave sensor includes a distance identification section for obtaining a relative distance to the object in the detection area, a movement-distance identification section for obtaining a movement distance per unit of time of the object in the detection area, and an object determination section that receives output from the distance identification section and the movement-distance identification section and carries out an operation for determining object detection by setting the movement distance value per unit of time, which is a threshold for determining object detection, smaller for longer relative distances to the object in the detection area.

Abstract: Film thickness measurement systems and methods are provided that utilize a signal generator having a Gunnplexer design and a resonant frequency detector to correlate the shift in resonant frequency experienced by a resonant cavity having one face abutting a test object. The shift is resonant frequency is determinative of a linear or near linear correlation between film thickness and the resonant frequency shift.

Abstract: A digital time domain reflectometer system is provided for performing a measurement process that is useful for calculating a cable length. The measurement process starts with a launch controller periodically generating a sync signal for turning a duration signal on. After a known delay time, the launch controller launches a signal on a cable, and if a reflected signal is detected, a detection circuit turns the duration signal off. A counter counts the number of clock pulses in the duration signal. This system is made more accurate by performing the measurement process multiple times and averaging the results. Using the averaged results, and compensating for the added known delay time, the cable length is calculated. An adaptive threshold may be used to enhance measurement accuracy.

Abstract: A microwave measurement system is utilized for the determination of displacement of a piston in a fluid filled cylindrical structure. The piston plus cylindrical encasement of the hydraulic system is modeled as a uniform cylindrical waveguide terminated in a metal plate. A novel shaped probe antenna to measure the slope of the relative phase of the reflected equivalent voltage wave with respect to frequency. The idea to measure the slope of the relative phase is novel and requires a new antenna structure. Instead of using the phase slope with respect to frequency, the total phase shift in a given frequency range is used to determine the location of the piston in the cylindrical chamber. Simulation and measurement will be used to determine the impedance of the antenna as well as the electromagnetic field at different locations inside the cylinder. In addition, the antenna will be analyzed to optimize its design, which ought to result in minimizing the reflections.

Abstract: A system for determining the depth of a fluid in a storage tank. The depth of the fluid is determined after the detection of a pulsed wave that is reflected from the top surface of the fluid. The system includes a transducer, an analog-to-digital converter, and a filter. The transducer is configured to sense the reflected pulsed wave and to generate an analog input signal that corresponds to the reflected pulsed wave. The analog-to-digital converter is coupled to the transducer, and configured to convert the analog input signal into a digital input signal. The filter is coupled to the analog-to-digital converter. The filter includes a finite impulse response filter that is configured to receive the digital input signal and to generate a digital output signal.

Abstract: A method and apparatus for monitoring a condition having a known relation to, or influence on, the transit time of a cyclically-repeating energy wave moving through a transmission channel, by: (a) transmitting a cyclically-repeating energy wave through the transmission channel from a transmitter at one end to a receiver at the opposite end; (b) continuously changing the frequency of the transmitter according to changes in the monitored condition while maintaining the number of waves in the transmission channel as a whole integer; and (c) utilizing the changes in frequency of the transmitter to provide a continuous indication of the monitored condition. Operation (b) is preferably performed by detecting a predetermined fiducial point in each cyclically-repeating energy wave received by the receiver, but may also be performed by the use of a phase-locked loop circuit, to maintain the number of energy waves in the loop of the transmission channel as a whole integer.

Abstract: Described is a radar filling level measuring device for non-contact measurement of a filling level of a filling matter in a vessel. A radar filling level measuring device including an electronics unit for generating transmission signals and for evaluating receiving signals reflected for a filling matter, an antenna unit connected to the electronics unit and adapted to radiate the transmission signals generated by the electronics unit in the direction of the filling matter and to receive the receiving signals reflected from the filling matter surface and to pass them on to the electronics unit, and a housing forming a cavity which is at least tight with respect to the atmosphere within the vessel and in which the electronics unit and antenna unit are acommodated. By this structure both the antenna unit and the electronics unit are protected in a technically simple and cheap way against aggressive ambient conditions and against chemical and mechanically abrasive aggression.

Abstract: The invention relates to a process for the non-destructive net weighing of capsules using microwaves.

Abstract: A radar level gauge for measuring the level of a surface of a product stored in a tank by use of radar. The radar transmits microwaves towards the surface and receives microwaves reflected by the surface and is adapted to transmit and receive microwaves within two widely separated frequency bands. Widely separated frequency bands are chosen to utilize the differences in attenuation due to foam on the surface and the differences in beam-width or other disturbances. The ratio between the center frequencies of the two widely separated frequency bands can be quantified as at least greater than 1.5:1 or preferably greater than 2:1.

Abstract: A system and method for sensing the proximity of an electronic device, in particular, a radio frequency mobile communication device such as a mobile telephone, wireless modem equipped portable computer, or the like to a body employs an antenna capable of altering its impedance for changing the amount of radio frequency electromagnetic energy reflected by the antenna when the antenna is in proximity to the body. The radio frequency electromagnetic energy reflected by the antenna is measured and used for determining proximity of the antenna to the body.

Abstract: The invention relates to a TDR fill level measuring device. A surface waveguide, along which the measuring signals are guided, is composed of a plurality of segments, which are arranged to telescope into, and out of, one another.

Abstract: A fill level measuring device working with microwaves, having an antenna for transmitting, or for transmitting and receiving, microwaves. The antenna has a metallic outer conductor and a ceramic inner conductor. The inner conductor is secured in a pressure-tight and gas-sealed manner in the outer conductor. A coating of a fluorothermoplastic is provided on the inner conductor or in the outer conductor. The inner conductor is secured in the outer conductor by means of a warm-pressed fit, and the inner conductor and the outer conductor have conical surfaces of equal shape in the region of the pressed fit.

Abstract: A LAN tester has display and remote units each having a connector jack attached to an adapter board for connection to the plug of a patch cord. Both the display and remote units have circuits which are capable of measuring the phase between a drive signal voltage and the corresponding coupled or reflected signal due to the drive signal. Scattering parameters for the mated connector pairs and the patch cord itself are measured during a field calibration. A computer in one or both of the tester units stores the measured scattering parameters and uses the scattering parameters to move the reference plane to any desired location along the patch cord. The length of the patch cord can be determined through the use of phase by measuring the frequency difference between adjacent maxima of a plot of input impedance versus frequency.

Abstract: An apparatus for measuring thickness in super-thin films consists of a special resonator unit in the form of an open-bottom cylinder which is connected to a microwave swept frequency microwave source via a decoupler and a matching unit installed in a waveguide that connects the resonator unit with the microwave source. The apparatus operates on the principle that thin metal film F, the thickness of which is to be measured, does not contact the end face of the open bottom of the cylindrical resonator sensor unit and functions as a bottom of the cylindrical body. The design of the resonator excludes generation of modes other than the resonance mode and provides the highest possible Q-factor. As the conductivity directly related to the film thickness, it is understood that measurement of the film thickness is reduced to measurement of the resonance peak amplitudes.

Abstract: Apparatus and methods of obtaining information concerning a substance (57) is provided by applying pulses (91, 92, 93) of electromagnetic energy to the substance (57) and evaluating the response of the substance to the electromagnetic energy. The pulses (91, 92, 93) generated by a source (51) are of sufficiently short duration to generate a very broad frequency band of energy. The pulsed energy is directed to the substance (57) to be processed and energy pulses (91, 92, 93) passing through the substance (57) are received (56) and analyzed (66) to determine the properties of substance (57).

Abstract: The invention is a process for determining the resistivity of a layered structure including a layer of resistive material hidden under a topcoat and a tile layer, the process comprises the steps of; 1) directing electromagnetic radiation over a selected frequency range to the outer surface of the layered structure; 2) measuring the reflection of the electromagnetic radiation from the layered structure surface; 3) converting the signal into the time domain; 4) analyzing the first echo to obtain the topcoat thickness; 5) obtaining the tile thickness from the time delay between the first and second echoes; 6) compensating the second echo with electromagnetic power loss due to the topcoat and tile; and 7) determining the resistance of the resistive layer from the compensated second echo.

Abstract: The present invention relates to a measuring device and a method for contactless detection of an angle of rotation or a torsional rotation. The measuring device includes a first resonator (2) and a second resonator (4). The two resonators (2, 4) have an essentially circular circumference, on which at least one protrusion and/or one recess is disposed. The two resonators (2, 4) are coplanar to one another and are also rotatable relative to one another. In addition, an exciter device (6) for exciting the resonators and a receiver device (6) for measuring a backscattered signal are present. Upon a relative rotation of the two resonators (2, 4) to one another, the resonant frequency changes, which is used as a measure for ascertaining the angle of rotation.

Abstract: A radar level gauge using microwaves coupable to a two-wire process control loop for measuring level of a product in a tank. A microwave antenna unit is directable into the tank. A low power microwave source sends a microwave signal through the antenna unit into the tank. A low power microwave receiver receives a reflected microwave signal from a surface of the product in the tank. Measurement circuitry coupled to the source and receiver initiates transmission of the microwave signal and for determining product level based upon the received signal. Output circuitry coupled to the two-wire process control loop transmits information related to product level over the loop. Power supply circuitry coupled to the two-wire process control loop receives power from the loop being the sole source of power for the low power microwave source, the low power microwave receiver, the measurement circuitry and the output circuitry in the radar level gauge.

Abstract: A dielectric rod antenna assembly for a level measurement system. The antenna assembly includes a transition structure housed within a coupling sleeve. The transition structure includes a short-circuited waveguide filled with a dielectric material and an exciter element projecting through the waveguide into the material. The transition structure directs electromagnetic energy through the bottom of the dielectric material into a rod antenna attached to the bottom of the coupling sleeve for propagation within the container. The dielectric material includes a longitudinal axial bore having a tapered tip to provide a dielectric-lined waveguide. The bottom end of the dielectric is encircled with a metal ring of a diameter larger than the dielectric to smooth the transition into the rod antenna.

Abstract: Testing of a printed circuit board (PCB) impedance measurement region is performed using time domain reflectometry (TDR) that measures reflections and time delays of pulses injected into an impedance measurement region (impedance coupon). Timing markers are used to give both visual and electrical indications of precisely where the desired impedance measurement region (impedance coupon) begins and ends. The timing markers are placed on either end of the impedance coupon to be measured and give explicit start and end points to the PCB impedance measurement region. The timing markers may be in any form which has a discernable impedance difference from the PCB impedance measurement region.

Abstract: A non-contacting linear position location system employs a special transmission line to encode and transmit magnetic signals to a receiver on the object whose position is to be measured. The invention is useful as a non-contact linear locator of moving objects, e.g., to determine the location of a magnetic-levitation train for the operation of the linear-synchronous motor drive system.

Abstract: A body scanning measurement, typing and profiling apparatus and method utilizing microwave energy. Microwaves are used to measure the size and shape of an individual. An array of miniaturized transmitting antennas direct RF energy to a similarly sized array of receiving antennas. Microwaves are directed toward an object, such as a human being, to be measured and the unabsorbed energy of the microwaves transmitted is measured and converted to a signal representative of the size and shape of the object being measured. A computer processor generates vital body measurements and stores such measurements for future use.

Abstract: A method and apparatus of measuring a predetermined parameter having a known relation to the transit time of movement of an energy wave through a medium, by transmitting from a first location in the medium a cyclically-repeating energy wave; receiving the cyclically-repeating energy wave at a second location in the medium; detecting a predetermined fiducial point in the cyclically-repeating energy wave received at the second location; continuously changing the frequency of transmission of the cyclically-repeating energy wave from the first location to the second location in accordance with the detected fiducial point of each received cyclically-repeating energy wave received at the second location such that the number of waves received at the second location from the first location is a whole integer; and utilizing the change in frequency to produce a measurement of the predetermined parameter.

Abstract: The invention relates to a device for determining and/or monitoring filling of a product or the position of the boundary surface between two media or phases in a container. The device comprises a signal generating unit that generates high-frequency measuring signals, an injection unit and a surface waveguide, wherein the measuring signals are injected into the surface waveguide by means of the injection unit and directed toward the filling product via the surface waveguide. The device also comprises a receiver/evaluation unit, which directly or indirectly determines filling of the product or the position of the boundary surface in the container during the running time of the measuring signals reflected on the surface or boundary surface of the filling product. The invention aims at providing a device which is configured in such a way that parasitic voltages are effectively diverted. This is achieved in that the surface waveguide is connected to a frame potential by means of a coupling.

Abstract: A method for electrical cable testing by Pulse-Arrested Spark Discharge (PASD) uses the cable response to a short-duration high-voltage incident pulse to determine the location of an electrical breakdown that occurs at a defect site in the cable. The apparatus for cable testing by PASD includes a pulser for generating the short-duration high-voltage incident pulse, at least one diagnostic sensor to detect the incident pulse and the breakdown-induced reflected and/or transmitted pulses propagating from the electrical breakdown at the defect site, and a transient recorder to record the cable response. The method and apparatus are particularly useful to determine the location of defect sites in critical but inaccessible electrical cabling systems in aging aircraft, ships, nuclear power plants, and industrial complexes.

Abstract: A separating drum 1 is provided with a device for determining the position, the composition and the nature of several layers of fluid settling upstream from barrier 8. The device comprises a first rod 12 provided with microwave beam emitters 13, a second rod 14 provided with microwave beam receivers 15, a microwave source 16 that can be connected to emitters 13, and means 17 for recording and analyzing the microwave beams received by receivers 15.

Abstract: A level sensor which is capable of largely eliminating the influence of structural parts and/or the formation of deposits on the measuring accuracy and on the measuring sensitivity of the level sensor. There is provided, a launching unit which has at least one length, which essentially corresponds to the distance from the container wall to the lower edge of the structural part, and which is positioned in such a manner that a transition area launching unit conductive element is located approximately in the plane of the lower edge of the structural part, with the diameter of the opening of the launching unit on the transition launching unit conductive element is in the order of magnitude of the wavelength of the high-frequency measurement signals.

Abstract: According to one embodiment of the invention, a computerized method for tuning a wire to have a particular electrical length is provided. The method includes providing a reference wire and the wire to be tuned. The method also includes transmitting a reference signal and a test signal over the reference wire and the wire, respectively, to a destination. The method also includes determining the time difference between arrival of the respective signals at the destination. The method also includes providing, based on the time difference, an indication of the location along the length of the wire where the wire has an electrical length approximately equal to the electrical length of the reference wire.

Abstract: A microwave measurement system is utilized for the determination of displacement of a piston in a fluid filled cylindrical structure. The piston plus cylindrical encasement of the hydraulic system is modeled as a uniform cylindrical waveguide terminated in a metal plate. A novel shaped probe antenna to measure the slope of the relative phase of the reflected equivalent voltage wave with respect to frequency. The idea to measure the slope of the relative phase is novel and requires a new antenna structure. Instead of using the phase slope with respect to frequency, the total phase shift in a given frequency range is used to determine the location of the piston in the cylindrical chamber. Simulation and measurement will be used to determine the impedance of the antenna as well as the electromagnetic field at different locations inside the cylinder. In addition, the antenna will be analyzed to optimize its design, which ought to result in minimizing the reflections.

Abstract: An antenna assembly suitable for use with a microwave-based level measurement system mounted on a vessel. The antenna assembly includes an installation thread, a shielded extension, and a rod antenna. The antenna assembly is screwed into a threaded portion in the opening of the vessel. The antenna assembly may be formed as a single integral unit molded from a polymer material. The antenna assembly may also be constructed with the installation thread, the shielded extension and the rod antenna comprising individual polymeric components which are welded together to form a unitary assembly. The polymer material is selected based on chemical resistant properties according to the application.

Abstract: A wall film monitoring system includes first and second microwave mirrors in a plasma processing chamber each having a concave surface. The concave surface of the second mirror is oriented opposite the concave surface of the first mirror. A power source is coupled to the first mirror and configured to produce a microwave signal. A detector is coupled to at least one of the first mirror and the second mirror and configured to measure a vacuum resonance voltage of the microwave signal. A control system is connected to the detector that compares a first measured voltage and a second measured voltage and determines whether the second voltage exceeds a threshold value. A method of monitoring wall film in a plasma chamber includes loading a wafer in the chamber, setting a frequency of a microwave signal output to a resonance frequency, and measuring a first vacuum resonance voltage of the microwave signal.

Abstract: The invention is a device for inspecting an assembly including a surface coating containing magnetic radar-absorbing materials on a conductive surface. In detail, the device includes a first system for transmitting an electromagnetic signal to the assembly, which includes a first waveguide made of a conductive material coupled in series to a second waveguide made of a dielectric material. A second system is provided for receiving the portion of the electromagnetic signal reflected from the assembly, which includes a third waveguide made of a conductive material coupled in series to a fourth waveguide made of a dielectric material. Thus the electromagnetic signal is transmitted from the first waveguide to the second waveguide on to the assembly and the portion of the electromagnetic signal reflected off the assembly is received by the fourth-waveguide and transmitted to the third, waveguide.

Abstract: According to one embodiment of the invention, a computerized method for tuning a wire to have a particular electrical length is provided. The method includes providing a reference wire and the wire to be tuned. The method also includes transmitting a reference signal and a test signal over the reference wire and the wire, respectively, to a destination. The method also includes determining the time difference between arrival of the respective signals at the destination. The method also includes providing, based on the time difference, an indication of the location along the length of the wire where the wire has an electrical length approximately equal to the electrical length of the reference wire.

Abstract: A system for investigating a sample, the system comprising a detector having non-linear current voltage characteristics and being configured to mix two radiation signals having frequencies in the range from 25 GHz to 100 THz, one of the signals being a local oscillator signal and the other signal being a sample signal carrying information about the sample being investigated, the system further comprising a quantum cascade laser for providing at least the local oscillator signal.

Abstract: The invention concerns a device for determining and/or monitoring the fill level of a fill material (2) in a container (3) with a transmitting-/receiving-unit (9, 10), which produces and receives high frequency measurement signals, and an evaluation-/control-unit (11), which determines the fill level of the fill material (2) in the container (3) on the basis of the travel time of the high frequency measurement signals. High frequency measurement signals are guided along a conductive element (6). The coupling onto, and from, element (6) is done by a coupling unit (8). The device is secured at the container using an attachment part (5) placed above the maximum fill level to be measured and/or monitored. In the upper region of the conductive element (6), a horn-shaped element (7) is arranged such that its lower opening area (15) facing in the direction toward the surface (4) of the fill material (2) lies approximately in the plane of the attachment part (5).

Abstract: Ground penetrating radar (GPR) is a technique that may be used to image the inside of a structure by collecting the echoes (or reflections) resulting from electromagnetic signals such as, for example, electromagnetic waves of typically high frequency, being radiated into the structure. Typically, the rebars inside a reinforced concrete structure are strong radar wave reflectors. Locating rebars within a reinforced concrete structure and determining their depths may be accomplished by analyzing the reflections, particularly the amplitudes and arrival times of the reflections, from the rebars in the reinforced concrete structure. Provided is a method and system for determining, for a substantially concrete structure having at least a first side and containing one or more reinforcing bars, a distance of the one or more reinforcing bars from the first side of the substantially concrete structure.

Abstract: A linear position sensor using time domain reflectometry (TDR) includes a rigid linear guide having a first end and a second end. The linear guide is made of a conductive material. A follower is provided having a central aperture. The follower is positioned with the linear guide passing through the central aperture. The follower is of a material that is influenced by a magnet. A TDR instrument is positioned at one end of the linear guide. The TDR instrument is adapted to send a TDR signal parallel to the linear guide which is directed at the follower. The TDR instrument receives a return signal reflected from the follower which indicates the linear positioning of the follower. At least one magnet is provided which is adapted for mounting on an object. The follower is magnetically attracted to or repulsed by the magnet to such an extent that the follower follows the movement of the magnet, thereby indicating the positioning of the object.

Abstract: A method of determining the salinity of an area of soil includes providing signal data from a radar scan of the area of soil. Improved vegetation correction is applied to the signal data using a Cloude decomposition method or a “xhv” method. In some circumstances existing vegetation correction methods are used and a synergistically improved corrected obtained. The corrected data is then inverted to determine the magnitude of the dielectric values. Salinity levels are calculated from each of the imaginary component of dielectric values.

Abstract: A level meter that employs the radar principle for measuring the fill level of a medium in a container, includes a signal generator for generating and transmitting an electromagnetic signal, an electrical conductor assembly for feeding the electromagnetic signal emanating from the signal generator into the container and returning the portion of the electromagnetic signal reflected by the medium in the container, and an evaluation electronics unit that receives the portion of the electromagnetic signal reflected by the medium in the container and determines its transit or run time and thus the fill level of the medium in the container. A transducer, differentiated from the conductor assembly, is provided for measuring an additional physical variable. This enhances the functional capabilities of the level meter.

Abstract: A system for detecting overlapped flat objects in a sequence of flat objects have at least one of their edges exposed for viewing as they pass along a feed path. The system includes a sensor for generating a signal in response to detecting a flat object in the feed path and a camera responsive to the signal for capturing a digital image of the exposed edges of the detected flat object in the feed path. A vision system is coupled to the camera for receiving the digital image. The vision system analyzes at least a portion of the image to determine a pixel density variation along a direction perpendicular to the edges and uses the pixel density variation to output an indication of the number of edges in the image.

Abstract: Testing of a printed circuit board (PCB) impedance measurement region is performed using time domain reflectometry (TDR) that measures reflections and time delays of pulses injected into an impedance measurement region (impedance coupon). Timing markers are used to give both visual and electrical indications of precisely where the desired impedance measurement region (impedance coupon) begins and ends. The timing markers are placed on either end of the impedance coupon to be measured and give explicit start and end points to the PCB impedance measurement region. The timing markers may be in any form which has a discernable impedance difference from the PCB impedance measurement region.

Abstract: A loop powered level measurement and time of flight ranging system with power management. The level measurement system comprises a controller, a transducer for distance ranging, a power supply, and a power management stage. The power management stage comprises a shunt current regulator and a circuit for charging a storage capacitor. The shunt current regulator shunts excess current from the current loop and the circuit charges the storage capacitor. The charging of the capacitor is monitored and stored energy is applied to the transducer to make a level measurement. During charging, the controller continues to operate a user interface and communication module.

Abstract: A method and apparatus for assessing standing tree stems for readiness for harvesting, or for determining cutting points for processing of felled tree stems, logs, or wood pieces, or for assessing stems, logs, or wood pieces for a particular end use, includes scanning with short-wave or microwave electromagnetic energy and processing the scan data to produce an image indicating the external shape or dimensions of the stem or log and hidden internal characteristics and their position, and assessing the image. Knots and/or whorls, which are not visible from the exterior and the depth of the clear wood sheath from the surface, may be determined.

Abstract: The microwave measuring device, which preferably operates with microwave bursts, serves to produce a measured value (XH) representing the level of the contents of a vessel (200). It comprises a transceiver unit (2) for generating a level-dependent intermediate-frequency signal (ZF) by means of a transmit signal (S2) and a receive signal (E2), and a transducer element (1) which in operation couples waves (S2), particularly pulsed waves, into the vessel under control of the transmit signal (S2) and converts echo waves (E1) reflected from the contents (201) of the vessel into the receive signal (E2). The intermediate-frequency signal (ZF) is fed to a control unit (3) of the level measuring device where it is stored in the form of a sampling sequence (AF) in a volatile data memory (33). In this manner, both amplitude information and phase information is available for the level measurement. The device is thus capable of measuring level with high accuracy, particularly accurately to a millimeter, and very fast.

Abstract: A method and apparatus is disclosed for measuring electrical properties of objects by the transmission of electromagnetic waves through a non-magnetizable material. The disclosure also describes a method of measuring changes in electromagnetic signals as the amplitude and frequency of the electromagnetic waves is varied to determine the thickness of an object.

Abstract: A radar level gauge using microwaves coupable to a two-wire process control loop for measuring level of a product in a tank. A microwave antenna unit is directable into the tank. A low power microwave source sends a microwave signal through the antenna unit into the tank. A low power microwave receiver receives a reflected microwave signal from a surface of the product in the tank. Measurement circuitry coupled to the source and receiver initiates transmission of the microwave signal and for determining product level based upon the received signal. Output circuitry coupled to the two-wire process control loop transmits information related to product level over the loop. Power supply circuitry coupled to the two-wire process control loop receives power from the loop being the sole source of power for the low power microwave source, the low power microwave receiver, the measurement circuitry and the output circuitry in the radar level gauge.

Abstract: The invention relates inter alia to a sensor system (50) used for distance calculation. A setpoint selection unit (58) controls an amplifier unit (54) and/or a sensor unit (52) depending on selectable setpoints for a cycle of detection. Contrary to known sensor systems, different detection cycles can be carried out in a very simple manner.

Abstract: A method for determining thickness of a layer in a structure comprising at least one layer by means of, e.g., ultra sound measurements. Selects a first reflection from a response signal and uses this reflection as a basis for predicting the shape of a further reflection. The second reflection is subsequently located in the response signal by comparing the response signal to the predicted shape.

Abstract: A radar level gauge for measuring the level of a surface of a product stored in a tank by use of a radar, where said radar transmits microwaves towards said surface and receives microwaves reflected by said surface and wherein said radar is adapted to transmit and receive said microwaves within two widely separated frequency bands. Widely separated frequency bands are chosen to utilize the differences in attenuation due to foam on the surface and the differences in beam-width or other disturbances. The ratio between the center frequencies of the two widely separated frequency bands can be quantified as at least greater than 1.5:1 or preferably greater than 2:1.