A method of determining an equivalent source associated with a device under test by an over-the-air test (OTA) test system is described. The OTA test system includes an analysis circuit and at least one measurement antenna. The method includes the steps of: conducting, by the at least one measurement antenna, at least two sets of measurements of electromagnetic waves emitted by the device under test, thereby generating measurement signals associated with the electromagnetic waves; determining, by the analysis circuit, at least one radiation parameter of the device under test based on the measurement signals, wherein the at least one radiation parameter is associated with the electromagnetic waves emitted by the device under test; and determining, by the analysis circuit, an equivalent source on a Huygens surface based on the at least one determined radiation parameter, wherein the equivalent source is associated with the device under test. The at least two sets of measurements are conducted on at least two measurement surfaces, wherein the at least two measurement surfaces are different from each other. Further, an OTA test system is described.

A sensor device according to an embodiment of the present technology includes a sensor head and a measurement unit. The sensor head includes a first probe and a second probe, the first probe including a first antenna section used for transmission, the second probe including a second antenna section used for reception, the second probe being situated at a specified distance from the first probe and facing the first probe. The measurement unit includes a signal generator that generates a measurement signal that includes information regarding characteristics of a propagation of an electromagnetic wave in a medium between the first and second antenna sections.

An apparatus for determining axial spacing between conductive rings of a slip ring assembly includes a signal generator that generates an incident signal, a plurality of conductive rings axially spaced along a shaft where the plurality of conductive rings includes a first conductive ring and a second conductive ring that are axially spaced at a first axial distance. The shaft and the plurality of conductive rings are submerged in a bath of a liquid or encased in an epoxy. A first twisted wire pair is electronically coupled at to the signal generator and to inputs of the first and second conductive rings. A second twisted wire pair is electronically coupled at one end to outputs of the first and second conductive rings. A method for determining axial spacing between conductive rings of a slip ring assembly is also disclosed.

A wireless power transmission system, and a method for controlling wireless power transmission and wireless power reception are provided. According to an aspect, a method for controlling a wireless power transmission may include: detecting a plurality of target devices used to wirelessly receive power; selecting a source resonating unit from among a plurality of source resonating units, based on the amount of power to be transmitted to one or more of the plurality of target devices, a coupling factor associated with one or more of the plurality of target devices, or both; and wirelessly transmitting power to a target device using the selected source resonating unit.

A wireless power transmission system, and a method for controlling wireless power transmission and wireless power reception are provided. According to an aspect, a method for controlling a wireless power transmission may include: detecting a plurality of target devices used to wirelessly receive power; selecting a source resonating unit from among a plurality of source resonating units, based on the amount of power to be transmitted to one or more of the plurality of target devices, a coupling factor associated with one or more of the plurality of target devices, or both; and wirelessly transmitting power to a target device using the selected source resonating unit.

System and method for implementing a Vector Network Power Meter (VNPM) as a new class of electronic test instrument that uses a novel topology based upon a reflectometer to combine the functionality of a Power Meter with that of a Vector Network Analyzer (VNA). The VNPM overcomes application limitations of the two existing classes of test instruments, including parallel and simultaneous measurement capability, in-circuit operation, and improved accuracy and repeatability by eliminating the calibration of interconnecting cabling. Also provided are alternate implementations of a correlator for the reflectometer which reduce the size and complexity of the correlator while extending its frequency range without limit.

At least one property of a complex liquid is determined utilizing first and second sensing devices for measuring a respective first and second physical parameter of the liquid and generating respective first and second measured data indicative thereof. A control unit connectable to the sensing devices is used for analyzing the first and second measured data and determining the at least one property of the complex liquid. The first measured data may be responsive to a relatively low-frequency electric or electromagnetic field induced in the liquid, and the second measured data may be a response of the liquid to a relatively high-frequency external electromagnetic field applied to it.

An RF impedance measurement circuit includes a sensing capacitor connectable with an RF signal path; a first amplitude detector and a first frequency divider, each coupled, with the measurement circuit in operation, to the RF signal path at a first terminal of the sensing capacitor; a second amplitude detector and a second frequency divider, each coupled, with the measurement circuit in operation, to a second terminal of the sensing capacitor; and a phase detection circuit connected to an output of the first frequency divider and to an output of the second frequency divider.

A first radio frequency scan of a plurality of electronic circuit devices fixed to a structural component of a physical structure can be initiated. Data can be received from each electronic circuit device that is scanned, the data received from each electronic circuit device indicating a first measured electrical impedance of a respective conductor connected to the electronic circuit device and an identifier assigned to the electronic circuit device. For each of the plurality of electronic circuit devices that are scanned, the received data can be stored to a first memory. The data for the electronic circuit devices forms a baseline measurement of the electronic circuit devices to which impedance data gathered from subsequent radio frequency scans of the electronic circuit devices is compared to determine whether any of the conductors of the electronic circuit devices have deformed or broken.

Provided is a technique for specifying a medium more simply. A medium sensor device includes an antenna, a storage unit that stores a medium identification table in which a medium corresponding to an antenna impedance has been determined beforehand, and a medium specification unit that specifies the impedance of the antenna and specifies a medium in the vicinity of the antenna by referring to the medium identification table.