Abstract: A method and apparatus for detecting an accumulation of particles with a medium such as the soot content in diesel engine oil including generating a first waveform at a first frequency and a first voltage level to produce a standing wave having a voltage null point where at least a portion of the standing wave is passed within a portion of the oil. Generating a second waveform at a second frequency and a second voltage level to place a signal associated with a second voltage null point at a detection location for determining the signal's null point voltage level. The percentage soot content of the oil may be determined by taking the ratio of the difference between the first voltage and the second voltage over the null point voltage at the detection point. This ratio is indicative of the percentage soot content. The first and second waveforms may be produced by a variable frequency microwave source that is coupled with a coaxial cable have a probe affixed to its distal end for immersion in the oil.

Abstract: Apparatus and methodology utilizing nearfield microwave technology to detect contraband/forbidden substances concealed within metallic containers. Apparatus and methodologic microwave operating frequency determines the metallic thickness through which detection is possible, and also the expectable “depths” for detection within a metallic container. Special and important attention is paid to the appropriate positional and distance locating of the invention apparatus relative to a suspected “substance-containing” metallic container for detection to be most effective. Preferably, this distance is substantially equal to the closest distance from the central radiating plane of a lens/antenna (which is employed, according to a preferred practice of the invention) at which a conductive, metallic surface will regeneratively parasitize the lens/antenna.

Abstract: A microwave measuring device for defining the load of a two-phase flow consisting of solids or liquid particles suspended in a gaseous medium transported in a predetermined direction within a feed duct of electrically conductive materials. Antennae for transmitting and receiving microwaves are penetrating into the feed duct at a predetermined spacing from each other and first and second rods are penetrating into the feed duct ahead of and behind the transmitting and receiving antennae to define, with the feed duct section delimited by them, a resonator. Auxiliary field rods ahead of and behind the first and second field rods short circuit microwaves input into the feed duct section which in consequence of reflection, diffraction or heterodyning have become distorted.

Abstract: A method and a device for analyzing a sensor device, in which the sensor device forms an electric resonator in an oscillating circuit energized with an external energization voltage. The current in the oscillating circuit is detected in the range of the resonant frequency, and then the current thus detected is multiplied by the external excitation voltage. Finally, the signal obtained by this multiplication is averaged.

Abstract: A method and apparatus for detecting an accumulation of particles with a medium such as the soot content in diesel engine oil including generating a first waveform at a first frequency and a first voltage level to produce a standing wave having a voltage null point where at least a portion of the standing wave is passed within a portion of the oil. Generating a second waveform at a second frequency and a second voltage level to place a signal associated with a second voltage null point at a detection location for determining the signal's null point voltage level. The percentage soot content of the oil may be determined by taking the ratio of the difference between the first voltage and the second voltage over the null point voltage at the detection point. This ratio is indicative of the percentage soot content. The first and second waveforms may be produced by a variable frequency microwave source that is coupled with a coaxial cable have a probe affixed to its distal end for immersion in the oil.

Abstract: Exemplary techniques for providing a test point in a printed circuit board (PCB) or other circuit device that minimizes or eliminates intrusive effects in the transmitted as well as the monitored data signal are disclosed. A deposited resistor is used to provide a connection between a signal electrode and a transmission line of the PCB. Where the transmission line is embedded, the PCB may also include a tap to connect the signal layer of the PCB (having the embedded transmission line) with the signal electrode at the surface layer of the PCB. The deposited resistor is intended to act as a voltage-divider resistor and to buffer any perturbations of the system resulting from the tap and the introduction of a probe. Additionally, the deposited resistor may be positioned relative to the transmission line as to provide a equalization capacitance to compensate for parasitic capacitance.

Abstract: An interferometric signal processing apparatus (10) producing an output signal from a first input signal (34) and a second input signal (34), the input signals (34) having substantially equal carrier frequencies, comprising a bridge (12) having a first arm (26) and a second arm (28), each arm having a first end (30) and a second end (32), the first and second input signals (34) being input to the first end (30) of the first and second arms (26, 28), respectively; a device-under-test (36) provided the first arm (26); a carrier suppressor (14) connected to the second ends (32) of the first and second arms (26, 28) to produce a carrier-suppressed signal at its output (A); an amplifier (16) arranged to amplify said carrier-suppressed signal; and a mixer (22, 24) responsive to the amplified carrier-suppressed signal and a carrier-dominated signal to produce the output signal; wherein the differential group delay between: the first end (30) of the first arm (26) and the output (A) of the carrier suppressor (14); an

Abstract: A resonator device for testing a material quantity in the tobacco-processing industry for existence of at least one foreign substance and/or for detecting at least one of weight, density and humidity level of the material includes a resonator housing having a through opening for the material to pass through and a testing region located inside the resonator housing to which the material can be moved at least in part. The device has at least one element that increases energy density of electromagnetic waves for increasing the energy density in at least a portion of the testing region.

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: A sensor for measuring the dielectric constant of a fluid uses time of flight measurements. The sensor has a conduit for the fluid, preferably a transmission line. The dielectric constant of the fluid affects tranmission of electrical energy along the transmission line. An electrical generator, having as output an electrical transient, is operably connected to one end of the transmission line for transmitting the electrical transient along the conduit, where propagation of the electrical conduit is affected by the fluid. A receiver is connected to the other end of the conduit for detecting electrical transients that have passed along the conduit from the electrical generator.

Abstract: High-sensitivity methods and systems for measuring small or trace concentrations of molecules of interest. A haptomeric material is positioned in contact with a fluid medium, and preferably within the peak E-field-volume of an electromagnetic probe. The haptomeric material will bind with high selectivity to the desired target substance (antigen), and the bound haptomer-antigen combination changes the observed dielectric properties, as seen from the electromagnetic probe. A load-pulled oscillator is the preferred detector configuration, but alternatively other electrical configurations can be used.

Abstract: A tunable ferroelectric component and a narrowband resonant circuit for measuring the loss of the ferroelectric component. The ferroelectric component may be a capacitor integrated in the resonant circuit. The testing method eliminates other sources of loss to isolate the loss due to the ferroelectric material and to demonstrate that this loss is low.

Abstract: The process determines the permeability of the magnetic material by disturbance of a hyper frequency coaxial line. In the process, a sample of the material is formed and placed in a hyper frequency coaxial line. The reflection and/or transmission of a hyper frequency electromagnetic wave on and/or through this coaxial line is measured and the result of this measurement is used to deduce the magnetic permeability of the material. The fractional volume of magnetic material in the sample compared with the volume of the disturbed coaxial line is less than 1%.

Abstract: A test coupon for measuring a dielectric constant of a memory module substrate has a plurality of test pattern layers each having a long trace and a short trace formed thereon. A first test pattern layer has an exposed surface and a second test pattern layer is formed internally. The first test pattern layer has probe pads respectively connected to the long and short traces of the first and second pattern layers. Probe pads of the first test pattern layer are connected to a via contact of the second test pattern layer by via holes. The via contact of the second pattern layer is connected to the long and short traces of the second pattern layer. The test coupon is used to measure the dielectric constant of a module board.

Abstract: An apparatus for evaluating dialectically-anisotropic materials comprising a plurality of microwave transmitters with differing planes of polarization, and a plurality of microwave receivers with differing planes of polarization, wherein each transmitter includes a means of modulating the microwave beam to be transmitted, the transmitters and receivers arranged, relative to a workpiece to be measured, so as to cooperate in communication therebetween, and wherein connected to each receiver is a processor to identify the received amplitude and phase of a component of the transmitted microwave beam, and to analyze by Fourier analysis the received signals to identify the principal axes, attenuations and phase shifts of the received microwave beam without requiring the phases of the transmitted microwave beams to be synchronized.

Abstract: A method for creating a full or partial transparency in a material comprising the steps of creating a first electromagnetic wave adjacent to the material, saturating the material with the first electromagnetic wave, creating a second electromagnetic wave having a frequency higher than the first electromagnetic wave, engaging the second electromagnetic wave with the material when the material is saturated for creating a transparency in the material with respect to the electromagnetic waves. An apparatus for creating a transparency in a material comprising a large coil, a small coil, a switch, a low noise amplifier (LNA), a receiver, a frequency generator, a pulsar, at least one or more capacitors and a power source.

Abstract: A method for determining flow velocities conducts an electromagnetic signal through a fluid flowing in a delivery line and additionally conducts the electromagnetic signal in a spatially delayed manner. A velocity, a velocity profile, and a volumetric fraction of each of the components of the fluid interacting with the electromagnetic wave is determined from a Doppler shift between the original electromagnetic signal and a resulting electromagnetic signal. An apparatus for determining flow velocities is also provided.

Abstract: Apparatus and method for determining the triacetin content in cigarette filter plugs during the manufacture of the filter plugs from a filter tow. The apparatus including a filter tow storage container, a filter tow stretching device, a device for feeding triacetin, to the filter tow, a plug-forming device, a device for dividing the plug into portions, a first microwave sensor disposed downstream of the plug-forming device, and a second microwave sensor disposed upstream of the feed device for the triacetin. The triacetin content is determined by transmitting a high frequency electromagnetic field through the filter plug both before and after the triacetin is added and measuring the frequency shift and spread of the electromagnetic field to determine mass signals At and AO, respectivley. AO is compared to At to calculate the triacetin content of the filter plug.

Abstract: A loop coupled microwave cavity, which uses a cylindrical cavity as the main body and has a lock hole on the top of the cavity in order to connect to a loop-coupling end formed by bending the long pin of an SMA connector. The long pin of the SMA extends into the cavity through the lock hole so that the top end of the long pin will touch the inner wall of the cavity to receive a microwave signal in TM012 mode to excite the cavity. On the other hand, the coaxial structure formed by the long pin and the lock hole is a quarter-wavelength transformer, so the SMA connector has both loop coupling and impedance transforming functions to increase the Q factor of the cavity. A diminutive sample is inserted into the cavity to perform the cavity perturbation method (CPM).

Abstract: Apparatus and method for in situ measurements of at least one property of a liquid contained within a vessel.

Abstract: A new method and apparatus for detecting and measuring the level of metal present on the surface of a substrate is achieved. Energy, in the form of rf or light or microwave energy, is directed at the surface of a wafer, the reflected energy or the energy that passes through the semiconductor substrate is captured and analyzed for energy level and/or frequency content. Based on this analysis conclusions can be drawn regarding presence and type of metal on the surface of the wafer. Furthermore, by inclusion of metal within the resonating circuit of an rf generator changes the frequency of the vibration and therefore detects the presence of metal.

Abstract: Systems, methods, and probe devices for electronic monitoring and characterization using absorbent media confined by a metallic mesh. The mesh allows a stream of liquid or gas to pass through the structure, so that the media will adsorb the material to which it is specific. This changes the permittivity of the media in which the electromagnetic field is propagating. This change in permittivity can be seen through the use of classical microwave methods such as phase shift, amplitude changes, frequency changes in a cavity or the frequency of an unbuffered oscillator. Some embodiments use a two cylinder structure, where an outer cylinder contains a material which selectively removes a chemical which may be in conflict with or would contaminate the sensing of the desired chemical. This outer cylinder does not play a part in the measurement because it is outside the metal shield which contains the measurement adsorbent, and is thus outside the electromagnetic field.

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: A novel microwave sensor (10, 60, 70, 90, 200, 250, 280) provides low-cost, robust measurement of the electrical properties of fluid substances. The sensor is suitable for use in an industrial vessel or pipe and employs parallel electrical transmission paths (12,14) that differ in electrical or physical length. The electrical length of each transmission path, which may be a two-way path caused by placing a reflective element in each path, is further determined by the electrical properties of the material under test. The frequency (f) of the signal being applied to the sensor is varied in a known manner such that the difference in the electrical lengths (&Dgr;L) of the transmission paths (12, 14) is caused to correspond to an odd integral multiple of a half wavelength. When the frequency is so adjusted and the signals that have traversed the transmission paths are allowed to coherently interfere with one another, then a minimum resultant signal or null is obtained.

Abstract: In a spectroscopic process a sample for producing a test spectral line or spectrum of at least one component contained in the sample is stimulated and the transmitted and/or emitted electromagnetic rays are used to create the test spectral line or spectrum. In order to improve such a spectroscopic process to such an extent that variations of certain parameters, which alter the shape and/or occurrence of a spectral line, are compensated, a comparison spectral line or spectrum of a known comparison material is produced under substantially the same parameters as the sample. The comparison spectral line or spectrum is compared with an ideal comparison spectral line or spectrum in order to calculate a transfer function, and the transfer function is applied to the test spectral line or spectrum in order to calculate a corrected test spectral line or spectrum.

Abstract: A filling level gage operating with microwaves, for measuring a filling level of a filling material (5) in a container (1), is provided which functions with a single antenna (7) constructed as simply as possible, and in which a minimum distance required for measurement between the filling material (5) and the antenna (7) is as small as possible, having a microwave generator (9), and an antenna (7) with planar antenna structure, which is used to transmit the microwaves in the direction of the filling material (5) and to receive microwaves reflected from a filling material surface, in which the planar antenna structure has at least two transmission and/or reception elements (11, 13, 33, 35, 37, S, E).

Abstract: Systems, methods, and probe devices for electronic monitoring and characterization using single-ended coupling of a load-pulled oscillator to a system under test.

Abstract: A method for taking measurements using a vector network analyzer (VNA) enables a reduction in interference created when the VNA is operated in the presence of external signals. For the method, three measurements are taken, one at a desired measurement frequency, another at a frequency slightly less than the desired measurement frequency, and another at a slightly greater frequency than the desired measurement frequency. An interfering signal may occur at or near the frequency of one of the three measurements. To eliminate measurement error from the interfering signal, the measurement signal with the median, or middle, magnitude is selected to provide the measurement results.

Abstract: 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 analysing the microwave beams received by receivers 15.

Abstract: A distance measurement system is provided. The distance measurement system includes at least one resonant circuit, at least one magnetic element with predetermined magnetic properties, a transmitter operable to transmit an electromagnetic pulse, a receiver operable to detect oscillations emitted by said resonant circuit in response to said electromagnetic pulse, and an analyzer operable to analyze an amplitude envelope property of said oscillations, to thereby determine a distance between the resonant circuit and the magnetic element.

Abstract: A method and system for measuring at least one of a plasma density and an electron density (e.g., in a range of 1010 to 1012 electrons/cm−3) using plasma induced changes in the frequency of a microwave oscillator. Measurement of at least one of the plasma density and the electron density enables plasma-assisted processes, such as depositions or etches, to be controlled using a feedback control. Both the measurement method and system generate a control voltage that in turn controls a plasma generator to maintain at least one of the plasma density and the electron density at a pre-selected value.

Abstract: A portable fuel analyzer includes a sensor, a processor and a display. The portable analyzer receives a fuel sample and the display identifies whether the vehicle fuel is tainted. The portable fuel analyzer is linked to an evaluation unit to determine a frequency measurement based upon signals from the sensor in the portable fuel analyzer. The evaluation unit provides a method of comparing the frequency from the vehicle fuel sensor with the frequency from the portable fuel analyzer. If the green LED is illuminated and the portable fuel analyzer indicates a different frequency than the vehicle fuel sensor, the vehicle fuel sensor is defective and should be replaced; If the green LED is illuminated and the portable fuel analyzer indicates the same frequency as the vehicle fuel sensor, a vehicle component other than the vehicle sensor is faulty; and, if the red LED is illuminated, the mixed fuel sample is tainted and a determination about the vehicle fuel sensor cannot be determined.

Abstract: A microwave microscope having a resonant slit formed in a highly conductive end of a microwave waveguide forming a probe tip. A short dielectric rod is fit into the waveguide near its conductive end. A longer dielectric rod is placed in back of the short dielectric rod with a small gap between the two rods. The length of the shorter rod and the size of the gap are chosen to form a dielectric resonator at the microwave frequency adjacent to the probe tip. Thereby, the impedance of the waveguide can be matched to the generally high impedance of the slit probe tip. Preferably, the dielectric constant of the materials is high, thereby reducing the size of the waveguide and probe tip relative to the microwave wavelength.

Abstract: A new method and apparatus for detecting and measuring the level of metal present on the surface of a substrate is achieved. Energy, in the form of rf or light or microwave energy, is directed at the surface of a wafer, the reflected energy or the energy that passes through the semiconductor substrate is captured and analyzed for energy level and/or frequency content. Based on this analysis conclusions can be drawn regarding presence and type of metal on the surface of the wafer. Furthermore, by inclusion of metal within the resonating circuit of an rf generator changes the frequency of the vibration and therefore detects the presence of metal.

Abstract: A method of determining at least one characteristic of one or more security documents such as banknotes, each security document including a sheet-like substrate of plastics material and opacifying layers applied to opposing faces of the substrate, the method comprising the steps of: (a) projecting radiation from a radiation source into the substrate of each security document for propagation therein, the opacifying layers acting to guide the projecting radiation within the substrate; (b) detecting a radiation emission of the substrate of each security document, the radiation emission resulting from the propagated radiation; and (c) analysing one or more characteristics of the radiation emission.

Abstract: A method is described for testing thin material wherein the material is irradiated with ultrasonic waves at least in certain areas and transmission of the ultrasonic waves through the material is determined and evaluated. The transmission of ultrasonic waves of different frequencies is thereby determined. The differences of the transmission at the different frequencies are then used to determine a criterion for evaluating the quality, in particular the porosity, of the irradiated material. Furthermore, a corresponding test device is described.

Abstract: A low voltage, low current apparatus for detecting discontinuities, such as bubbles, in a fluid stream, in which a tube is placed between a transducer transmitting successive bursts of ultrasonic energy and for receiving the bursts. The receiving transducer is connected to a low current transistor amplifier circuit of a signal processing circuit which keeps an output in a first state when signals are received corresponding to the presence of a fluid and in a second state when the bursts of energy are modified by the discontinuity.

Abstract: In a method for the nondestructive quality testing of a thermocouple (10) which can be used in particular at high temperatures and/or under high levels of vibration, which thermocouple (10) comprises at least two wires (13, 14) which run substantially parallel to one another in one plane, are connected to one another at their ends by a welded joint (15), are surrounded by a hermetically sealed sheath (11) and inside the sheath (11) are embedded in insulation (16, 17) comprising a compacted powder, simple and reliable assessment is achieved by the fact that the X-radiation is passed through the thermocouple (10) perpendicular to the plane of the wires (13, 14) and an X-ray image is taken, that the position of the wires (13, 14) in the vicinity of the welded joint (15) is determined from the X-ray image, and that the quality of the thermocouple (10) is established from the position of the wires (13, 14) in the vicinity of the welded joint (15).

Abstract: The present invention relates to a method and system for using microwave radiation to detect contraband hidden inside of a non-metallic container, such as a pneumatic vehicle tire. The method relies on the attenuation, retardation, time delay, or phase shift of microwave radiation as it passes through the container plus the contraband. The method is non-invasive, non-destructive, low power, and does not require physical contact with the container.

Abstract: Transceiver and methods are disclosed that are especially suitable for detecting metallic materials, such as metallic mines, within an environment. The transceiver includes a digital waveform generator used to transmit a signal into the environment and a receiver that produces a digital received signal. A tracking module preferably compares an in-phase and quadrature transmitted signal with an in-phase and quadrature received signal to produce a spectral transfer function of the magnetic transceiver over a selected range of frequencies. The transceiver initially preferably creates a reference transfer function which is then stored in a memory. Subsequently measured transfer functions will vary depending on the presence of metal in the environment which was not in the environment when the reference transfer function was determined. The system may be utilized in the presence of other antennas, metal, and electronics which may comprise a plastic mine detector for detecting plastic mines.

Abstract: In a vector network analyzer with a transmitting and, a receiving side, each including a downward mixing super heterodyne receiver, a high voltage power supply for providing an accelerating voltage is arranged in series with a second power supply with a controllable lower output voltage so that unavoidable voltage variations in the acceleration voltage can be controlled. The second power supply is connected to the output of a phase and frequency discriminator by way of an amplifier and a low-pass filter. The discriminator has two inputs, one receiving the downwardly mixed transmitting side signal and the other the signal provided by a reference oscillator having a constant frequency. As millimeter wave oscillator a backward wave oscillator is used whose frequency drifting by temperature changes or by aging is compensated for by a control signal for the second power supply, which control signal is derived from the phase and frequency discriminator.

Abstract: An improved method and apparatus for microwave imaging of an inhomogeneous target, in particular of biological tissue, compensates for the interactions between active antennae and nonactive antennae. Measured electric field data are processed in magnitude and phase form so that unwrapped phase information may be used directly in the image reconstruction. Initial finite element measurements and calculations are used to determine the perimeter dimensions of the target being examined, resulting in more accurate image reconstructions. An improved regularization technique is a hybrid of a Marquardt regularization scheme with a spatial filtering technique and a Tikhonov regularization scheme. An improved switching matrix enables simultaneous sampling of electric field data from a plurality of receiving antennae.

Abstract: A method of detecting impurities in a mass, such as detecting metallic and/or plastic particles in a stream of tobacco particles or filter material for tobacco smoke, includes the steps of moving the mass relative to a microwave field and/or vice versa, and analyzing the influence of the mass upon the microwave field. The analyzing step involves simultaneously measure the actual values of a first and a second parameter of the microwave field, ascertaining the presence or absence of those changes of the parameters which are attributable to the presence of impurities in the mass, determining whether or not the changes are within an acceptable range, and generating signals for segregation of impurities-containing portions of the mass from the other portions when the changes are outside of the acceptable range.

Abstract: The invention relates to a method and a measuring arrangement for measuring the gas content of a fluid (13). The fluid (13) comprises gas bubbles. In the method, microwave radiation (20) is transmitted through the fluid (13) and a signal (7) indicating the travel time, phase or amplitude of the radiation (20) is formed in a microwave measuring device (16), and a gas measuring equipment (18) determines the gas content of the fluid (13) by means of the signal (7).

Abstract: An interferometric signal processing apparatus (10) producing an output signal from a first input signal (34) and a second input signal (34), said input signals (34) having substantially equal carrier frequencies, comprising:

Abstract: A static DC magnetic field is externally applied to a targeted surface portion of protectively coated steel to vary the amount of microwave energy absorbed therein. Measurements of varying amounts of absorbed microwave energy are compared by coordination with corresponding measurements of the strength of the applied magnetic field varied in response to coating hidden deposit of corrosion products on the targeted surface portion of the steel, to provide a basis for detection of the corrosion involved.

Abstract: A method for determining flow velocities conducts an electromagnetic signal through a fluid flowing in a delivery line and additionally conducts the electromagnetic signal in a spatially delayed manner. A velocity, a velocity profile, and a volumetric fraction of each of the components of the fluid interacting with the electromagnetic wave is determined from a Doppler shift between the original electromagnetic signal and a resulting electromagnetic signal. An apparatus for determining flow velocities is also provided.

Abstract: A method is provided for creating a spectral EM frequency to calculate the thickness of a material with unknown permeability and conductivity using metallic transparencies. The method comprises the steps of testing empirically to approximate the conductivity, testing empirically to approximate the permeability, creating a first set of electromagnetic waves adjacent to the material to be measured of a relatively low frequency, impinging the first set of electromagnetic waves on the material for saturating the material, creating a second set of electromagnetic waves having specific constant amplitude of a higher frequency than the first set of electromagnetic waves, the second set of electromagnetic waves for engaging the material and generating a sensing signal having modified characteristics, and receiving the sensing signal through the saturated material such that the modified characteristics of the sensing signal are processed to determine the thickness of the material.

Abstract: A method for monitoring characteristics of materials includes placing a material in an application zone, measuring a change in at least one property value of the application zone caused by placing the material in the application zone and relating changes in the property value of the application zone caused by the material to at least one characteristic of the material An apparatus for monitoring characteristics of a material includes a measuring device for measuring a property value resulting from applying a frequency signal to the application zone after placing a material in the application zone and a processor for relating changes in the property value caused by placement of the material in the application zone to at least one desired characteristic of the material. The application zone is preferably a resonant cavity.

Abstract: A substrate inspection device successively stacks a first electrode plate, a standard substrate, a second electrode plate, a sample substrate, and a third electrode plate, in that order, with the sample substrate and the standard substrate placed in symmetrical opposition. A network analyzer both measures the propagation characteristics of RF electromagnetic waves from the second electrode plate to the first electrode plate as standard characteristics and measures the propagation characteristics of RF electromagnetic waves from the second electrode plate to the third electrode plate as the test characteristics. The quality of the sample substrate can be determined by comparing the measured standard characteristics with the test characteristics, thereby enabling, for example, the simple detection of defects inside a multilayer sample substrate.