The present exemplary embodiments provide a signal detection circuit and a sensor which improve a quality factor of a resonator by modeling an initial state of the resonator using an attenuator and a phase shifter which are modeling paths and significantly change a transmission coefficient of the resonator even with a small variation of an object to be measured.

A device for measuring a microwave surface resistance of a dielectric conductor deposition interface includes: a test platform, a calibration component, a sealing cavity and a support plate; wherein the test platform comprises: a shielding cavity having an open bottom, a dielectric rod, an input coupling structure, an output coupling structure, and a dielectric supporter; the dielectric conductor test sample and the test platform form a TE.sub.0m(n+δ) mode dielectric resonator; the calibration component and the dielectric conductor test sample are mounted on the test platform to measure corresponding quality factors, thereby calculating the microwave surface resistance of the deposition interface of the dielectric conductor test sample. The present invention requires no pre-measurement of relative permittivity and loss tangent of the dielectric conductor test sample. After calibration, the microwave surface resistance of the dielectric conductor deposition interface can be obtained by only one non-destructive measurement.

The invention relates to a distance-measuring device for determining a distance between a reflection body in a conducting structure and a coupling region for electromagnetic waves, which region is provided on an end section of the conducting structure, said measuring device comprising a transmitting and receiving device, and a conduction junction (1) provided on the coupling region, for coupling the transmitting and receiving device to the conducting structure containing a medium, in order to couple an electromagnetic wave into the conducting structure, and to decouple the electromagnetic wave, reflected on the reflection body, from the conducting structure. Said measuring device also comprises an evaluation device for determining the distance between the coupling region and the reflection body from the complex reflection coefficient between the coupled electromagnetic wave and the decoupled electromagnetic wave. The invention also relates to the corresponding method.

A method of evaluating microwave characteristics includes the steps of: (A) measuring thermal diffusion features and microwave characteristics of at least three mode samples to obtain at least three data points, wherein the mode samples include identical constituents but at different ratios thereof; (B) obtaining a mathematical relation between the data points by linear regression; (C) measuring a thermal diffusion feature of a sample under test, wherein the sample under test and the mode samples include identical constituents; and (D) substituting the thermal diffusion feature of the sample under test into the mathematical relation to evaluate a microwave characteristic of the sample under test. The method is applicable to a ceramic material to evaluate microwave characteristics of the ceramic material.

An impedance detector includes a sensing circuit with an adjustable impedance. The sensing circuit is coupled to a signal path. Further, an evaluation circuit is coupled to the sensing circuit.

An impedance detector includes a sensing circuit with an adjustable impedance. The sensing circuit is coupled to a signal path. Further, an evaluation circuit is coupled to the sensing circuit.

Various implementations include systems and approaches for measuring an electromagnetic impedance characteristic of a fluid under test (FUT) in a fluid channel. In some cases, a system includes: a transmitting electrode assembly including: a transmitting electrode having a transmitting surface; and a transmitting electrode backer ground plate at least partially surrounding the transmitting electrode; a receiving electrode assembly including: a receiving electrode having a receiving surface; and a receiving electrode backer ground plate at least partially surrounding the receiving electrode, where the transmitting electrode and the receiving electrode are located in a set of walls defining the fluid channel, the transmitting surface and the receiving surface each conform to a shape of the set of walls defining the fluid channel, where the fluid channel permits transverse flow of the FUT relative to both the transmitting electrode and the receiving electrode.

Various implementations include systems and approaches for measuring an electromagnetic impedance characteristic of a fluid under test (FUT) in a fluid channel. In some cases, a system includes: a transmitting electrode assembly including: a transmitting electrode having a transmitting surface; and a transmitting electrode backer ground plate at least partially surrounding the transmitting electrode; a receiving electrode assembly including: a receiving electrode having a receiving surface; and a receiving electrode backer ground plate at least partially surrounding the receiving electrode, where the transmitting electrode and the receiving electrode are located in a set of walls defining the fluid channel, the transmitting surface and the receiving surface each conform to a shape of the set of walls defining the fluid channel, where the fluid channel permits transverse flow of the FUT relative to both the transmitting electrode and the receiving electrode.

A system for passive microwave remote sensing using at least one microwave radiometer includes a fixed body portion, the fixed body portion being configured to attach to a mobile platform, and a mobile body portion, the mobile body portion being configured for rotatably coupling with the fixed body portion for rotation about a rotation axis. The mobile body portion is configured for supporting the at least one microwave radiometer therein such that the at least one microwave radiometer rotates about the rotation axis when the mobile body portion is rotated about the rotation axis such that a polarization axis of the at least one radiometer is aligned with an earth axis. The fixed body portion includes a motor mechanism for effecting rotation of the mobile body portion such that the at least one microwave radiometer provides a vertical scanning below and above the mobile platform.

A system and method for measuring resistance over an array. The array includes at least three electrodes. Nodes at each intersection between input electrodes and output electrodes have variable resistance. A driving voltage is applied to a selected input electrode and an output current is received at a selected output electrode. A selected node is at the intersection of the two selected electrodes and includes an electrical component with a resistive property. Remaining electrodes are connected with a ground for isolating the selected node from the effects of changes in impedance of the remaining nodes. The driving voltage is converted to an output current by resistance at the selected node. The output current is converted to an output voltage with a current-to-voltage converter circuit for measuring the resistance of the electrical component. The nodes may be measured as the selected node in sequential or non-sequential patterns.