Abstract: Circularly-polarized antennas and their methods of use for active holographic imaging through barriers. The antennas are dielectrically loaded to optimally match the dielectric constant of the barrier through which images are to be produced. The dielectric loading helps to remove barrier-front surface reflections and to couple electromagnetic energy into the barrier.

Abstract: The present invention includes methods and apparatuses for imaging material properties in natural-fiber-containing materials. In particular, the images can provide quantified measures of localized moisture content. Embodiments of the invention utilize an array of antennas and at least one transceiver to collect amplitude and phase data from radiation interacting with the natural-fiber-containing materials. The antennas and the transceivers are configured to transmit and receive electromagnetic radiation at one or more frequencies, which are between 50 MHz and 1 THz. A conveyance system passes the natural-fiber-containing materials through a field of view of the array of antennas. A computing device is configured to apply a synthetic imaging algorithm to construct a three-dimensional image of the natural-fiber-containing materials that provides a quantified measure of localized moisture content. The image and the quantified measure are both based on the amplitude data, the phase data, or both.

Abstract: Circularly-polarized antennas and their methods of use for active holographic imaging through barriers. The antennas are dielectrically loaded to optimally match the dielectric constant of the barrier through which images are to be produced. The dielectric loading helps to remove barrier-front surface reflections and to couple electromagnetic energy into the barrier.

Abstract: The present invention includes methods and apparatuses for imaging material properties in natural-fiber-containing materials. In particular, the images can provide quantified measures of localized moisture content. Embodiments of the invention utilize an array of antennas and at least one transceiver to collect amplitude and phase data from radiation interacting with the natural-fiber-containing materials. The antennas and the transceivers are configured to transmit and receive electromagnetic radiation at one or more frequencies, which are between 50 MHz and 1 THz. A conveyance system passes the natural-fiber-containing materials through a field of view of the array of antennas. A computing device is configured to apply a synthetic imaging algorithm to construct a three-dimensional image of the natural-fiber-containing materials that provides a quantified measure of localized moisture content. The image and the quantified measure are both based on the amplitude data, the phase data, or both.

Abstract: A method and apparatus to remove human features utilizing at least one transmitter transmitting a signal between 200 MHz and 1 THz, the signal having at least one characteristic of elliptical polarization, and at least one receiver receiving the reflection of the signal from the transmitter. A plurality of such receivers and transmitters are arranged together in an array which is in turn mounted to a scanner, allowing the array to be passed adjacent to the surface of the item being imaged while the transmitter is transmitting electromagnetic radiation. The array is passed adjacent to the surface of the item, such as a human being, that is being imaged. The portions of the received signals wherein the polarity of the characteristic has been reversed and those portions of the received signal wherein the polarity of the characteristic has not been reversed are identified. An image of the item from those portions of the received signal wherein the polarity of the characteristic was not reversed is then created.

Abstract: An RF tag system, comprising an RF reader configured to issue a plurality of different RF commands and to provide a continuous RF illumination field, and a plurality of RF tags respectively including a permanent identification; wherein the plurality of RF tags are configured to respond to a certain RF command from the RF reader by transmitting their respective identifications by way of backscatter modulation of the RF illumination field, and wherein the RF tags are further configured to perform the responding by way of respective independently selected random radio frequencies and timeslots from respective pre-defined ranges of radio frequencies and timeslots.

Abstract: An RF tag system, comprising an RF reader configured to issue a plurality of different RF commands and to provide a continuous RF illumination field, and a plurality of RF tags respectively including a permanent identification; wherein the plurality of RF tags are configured to respond to a certain RF command from the RF reader by transmitting their respective identifications by way of backscatter modulation of the RF illumination field, and wherein the RF tags are further configured to perform the responding by way of respective independently selected random radio frequencies and timeslots from respective pre-defined ranges of radio frequencies and timeslots.

Abstract: A system for measuring the hardness of cartridge cases employs an eddy current probe for inducing and sensing eddy currents in each cartridge case. A first component of the sensed signal is utilized in a closed loop system for accurately positioning the probe relative to the cartridge case both in the lift off direction and in the tangential direction, and a second component of the sensed signal is employed as a measure of the hardness. The positioning and measurement are carried out under closed loop microprocessor control facilitating hardness testing on a production line basis.

Abstract: A method and apparatus are described for performing X-ray fluorescence analysis where the physical relationship between the source/detector and the object being examined is not controlled. This technique and apparatus is particularly advantageous in performing an in situ analysis of the concentration of one or more elements present in a matrix of a material such as rock. In accordance with this aspect of our invention, such a mineral assay is performed by drilling a borehole into the matrix, inserting into the borehole a probe containing a suitable XRF source/detector, irradiating the matrix, detecting the spectrum of radiation that is produced and analyzing this spectrum.