Abstract: A microwave and millimeter wave imaging system. In either a far-field or a near-field detection mode, a radially-polarized probe transmits an imaging signal along a predetermined scan path to detect a target in a sample. The imaging signal's orientation is independent of the target's orientation and changes at each target as the probe transmits the signal during scanning. A measurement system receives scattered waves reflected from the sample via a single channel and images the sample and the target based on the reflected waves independent of the orientation of the target.

Abstract: Microwave and millimeter wave imaging. An antenna array in communication with a signal source comprises a plurality of antennas by which a signal generated by the signal source is transmitted incident to an object located remotely from the antenna array and by which a signal reflected from the object is received by the antenna array. The signals transmitted by the antennas collectively have an effective electric field resembling a plane-wave within a target region in front of the antenna array. A plurality of detectors each connected to one of the antennas is configured to simultaneously receive the reflected signal and provide an output signal representative thereof. An image processor configured to execute an imaging algorithm generates a multi-dimensional profile representative of the object based on the output signals from the detectors.

Abstract: Utilizing microwave reflections to compare a reference device with counterfeit and/or aging devices under test. The reflection from the device under test varies based on certain properties, which results in each device having a unique and intrinsic electromagnetic signature. Comparisons of the electromagnetic signature of the device under test to the electromagnetic signature of a reference device enable evaluating the acceptability of the device under test.

Abstract: A method of manufacturing a tire is provided that includes curing the tire (10) in a curing press (12) and applying microwave energy at a given frequency band into the tire. The interaction between the microwave energy and the tire is monitored to obtain a complex reflection coefficient. A root-mean-squared error is calculated using the measured complex reflection coefficient and a reference reflection coefficient. The reference reflection coefficient is from a fully cured tire made from the same material as the tire. Continuous monitoring of the interaction takes place to obtain the complex reflection coefficient along with continuous calculation of the root-mean-squared error at different times during the curing of the tire in the curing press. The calculated root-mean-squared errors are used to determine whether to stop the curing of the tire in the curing press.

Abstract: Utilizing microwave reflections to compare a reference device with counterfeit and/or aging devices under test. The reflection from the device under test varies based on certain properties, which results in each device having a unique and intrinsic electromagnetic signature. Comparisons of the electromagnetic signature of the device under test to the electromagnetic signature of a reference device enable evaluating the acceptability of the device under test.

Abstract: A method of manufacturing a tire is provided that includes curing the tire (10) in a curing press (12) and applying microwave energy at a given frequency band into the tire. The interaction between the microwave energy and the tire is monitored to obtain a complex reflection coefficient. A root-mean-squared error is calculated using the measured complex reflection coefficient and a reference reflection coefficient. The reference reflection coefficient is from a fully cured tire made from the same material as the tire. Continuous monitoring of the interaction takes place to obtain the complex reflection coefficient along with continuous calculation of the root-mean-squared error at different times during the curing of the tire in the curing press. The calculated root-mean-squared errors are used to determine whether to stop the curing of the tire in the curing press.

Abstract: Microwave and millimeter wave imaging. An antenna array in communication with a signal source comprises a plurality of antennas by which a signal generated by the signal source is transmitted incident to an object located remotely from the antenna array and by which a signal reflected from the object is received by the antenna array. The signals transmitted by the antennas collectively have an effective electric field resembling a plane-wave within a target region in front of the antenna array. A plurality of detectors each connected to one of the antennas is configured to simultaneously receive the reflected signal and provide an output signal representative thereof. An image processor configured to execute an imaging algorithm generates a multi-dimensional profile representative of the object based on the output signals from the detectors.

Abstract: An open-ended waveguide probe including a finite flange extending outwardly and functioning as an infinite flange. A signal source provides a microwave signal to the waveguide, which in turn transmits microwave electromagnetic energy incident upon an object to be tested. The finite flange at the waveguide's aperture is shaped to reduce scattering of the electromagnetic field reflected from the object and received by the aperture. The probe is adapted for coupling to a receiver for sampling the reflected electromagnetic field received by the aperture and the receiver is adapted for coupling to a processor for determining at least one material characteristic of the object based on sampled electromagnetic field reflected from the object.

Abstract: A method of inspection of a tire was developed using microwave imaging comprising the steps of selecting a plurality of regions from within a tire to be imaged; determining the dielectric properties of the tire components in each of the selected regions in a plurality of frequency bands; selecting a specific location on a tire to be imaged; providing a scanning platform for microwave imaging of the tire; imaging the selected location on a tire using microwave imaging at a plurality of microwave scanning frequencies and at a selected microwave polarization to obtain images of the internal state of the sample; and filtering the images to remove the effects of curvature of the selected location of the tire.

Abstract: Wideband synthetic aperture radar (SAR) imaging. A probe transmits a signal through its aperture incident to an object located in a medium of interest remotely from the probe. The probe receives through the aperture a plurality of nonuniformly sampled reflected signals from the object as the probe moves in a measurement plane located a predetermined distance from the object. A processor executes a SAR-based reconstruction algorithm to generate an image.

Abstract: Analyzing a device under test (“DUT”) at higher frequencies. A phase shifter varies the phase of a standing wave on a transmission line coupled to the DUT. The standing wave magnitude is sampled at each of the phase shifts and one or more DUT characteristics are determined as a function of the sampled magnitudes and phase shifts. Further aspects include a related phase shifter comprising a waveguide having a plurality of sub-resonant slots formed therein and having active elements for loading the slots to control the phase shift applied to the signal.

Abstract: A holographic imaging system including a transmission line coupled to an antenna at one end and to a signal source at another end. The antenna defines an aperture through which a signal generated by the signal source is transmitted incident to an object located remotely from the aperture and through which a signal reflected from the object is received by the antenna aperture. A standing wave probe phase-referenced to the antenna aperture samples the reflected signal. A detector connected to the standing wave probe receives the sampled reflected signal and provides an output signal that represents a real-valued signal proportional to an in-phase component of the reflected signal from the object. A processor executes an imaging algorithm for generating a multi-dimensional profile representative of the object based on the output signal from the detector.

Abstract: An open-ended waveguide probe including a finite flange extending outwardly and functioning as an infinite flange. A signal source provides a microwave signal to the waveguide, which in turn transmits microwave electromagnetic energy incident upon an object to be tested. The finite flange at the waveguide's aperture is shaped to reduce scattering of the electromagnetic field reflected from the object and received by the aperture. The probe is adapted for coupling to a receiver for sampling the reflected electromagnetic field received by the aperture and the receiver is adapted for coupling to a processor for determining at least one material characteristic of the object based on sampled electromagnetic field reflected from the object.

Abstract: A method of inspection of a tire was developed using microwave imaging comprising the steps of selecting a plurality of regions from within a tire to be imaged; determining the dielectric properties of the tire components in each of the selected regions in a plurality of frequency bands; selecting a specific location on a tire to be imaged; providing a scanning platform for microwave imaging of the tire; imaging the selected location on a tire using microwave imaging at a plurality of microwave scanning frequencies and at a selected microwave polarization to obtain images of the internal state of the sample; and filtering the images to remove the effects of curvature of the selected location of the tire.

Abstract: A holographic imaging system including a transmission line coupled to an antenna at one end and to a signal source at another end. The antenna defines an aperture through which a signal generated by the signal source is transmitted incident to an object located remotely from the aperture and through which a signal reflected from the object is received by the antenna aperture. A standing wave probe phase-referenced to the antenna aperture samples the reflected signal. A detector connected to the standing wave probe receives the sampled reflected signal and provides an output signal that represents a real-valued signal proportional to an in-phase component of the reflected signal from the object. A processor executes an imaging algorithm for generating a multi-dimensional profile representative of the object based on the output signal from the detector.

Abstract: Wideband synthetic aperture radar (SAR) imaging. A probe transmits a signal through its aperture incident to an object located in a medium of interest remotely from the probe. The probe receives through the aperture a plurality of nonuniformly sampled reflected signals from the object as the probe moves in a measurement plane located a predetermined distance from the object. A processor executes a SAR-based reconstruction algorithm to generate an image.

Abstract: Non-destructive imaging of an object. An imaging head supported on a rotatable arm samples an electric field scattered by the object at a plurality of locations as the arm rotates about a central axis, with the locations corresponding to a defined spatial domain located remotely from the object. One or more processors execute computer-readable instructions for controlling rotation of the arm and generating a multi-dimensional profile representative of the object in the defined spatial domain based on the sampling.

Abstract: Analyzing a device under test (“DUT”) at higher frequencies. A phase shifter varies the phase of a standing wave on a transmission line coupled to the DUT. The standing wave magnitude is sampled at each of the phase shifts and one or more DUT characteristics are determined as a function of the sampled magnitudes and phase shifts. Further aspects include a related phase shifter comprising a waveguide having a plurality of sub-resonant slots formed therein and having active elements for loading the slots to control the phase shift applied to the signal.

Abstract: Analyzing a device under test (“DUT”) at higher frequencies. A phase shifter varies the phase of a standing wave on a transmission line coupled to the DUT. The standing wave magnitude is sampled at each of the phase shifts and one or more DUT characteristics are determined as a function of the sampled magnitudes and phase shifts. Further aspects include a related phase shifter comprising a waveguide having a plurality of sub-resonant slots formed therein and having active elements for loading the slots to control the phase shift applied to the signal.

Abstract: A switched-slot sensor for use in a sensor array for microwave and/or millimeter wave imaging. The locations of a plurality of sensors in the array define a spatial domain away from an object for detecting an electric field from the object. Each of the sensors has an out-of-plane transmission line and outputs a signal representative of the measured field and the location of the sensor. A processor decodes the signals and generates an image of the object.