Abstract: An array antenna with dual polarization elements is provided. Each dual polarization element comprises a first sub-element and a second sub-element, each of which comprises a radiator that is embodied in and/or on a planar member and a balanced feed for the radiator that divides the radiator into two sections that that are mirror images of one another relative to a plane that passes through the balanced feed structure and is perpendicular to the planar member. Further, the radiator of the first sub-element is positioned to lie in an isolation plane associated with the second sub-element. Two such elements are positioned with respect to one another so that the planar members associated with the first elements are coplanar.

Abstract: An apparatus and method for active noise cancellation, including but not limited to, noise cancellation at VLF frequencies. The invention facilitates the reception of critical information in variable and extreme EMI scenario with no information about the signal of interest. The invention utilizes an automated, signal agnostic active noise cancellation technique and associated hardware components. In order to extract the signal of interest, vector modulation is employed to the signal from the noise only antenna so as to match it and then subtract it from the received signal containing combined noise and signal of interest. This apparatus and method ensures that a signal of interest can be extracted from an extremely noisy environment without any knowledge about the characteristics of that signal.

Abstract: The present invention is directed to a monopole/dipole symmetric radiator structure that includes a symmetric planar radiator. When the symmetric radiator is part of an operative monopole or dipole antenna, the antenna exhibits a wide or broad bandwidth, a VSWR of less than about 3:1, a relatively constant gain perpendicular or broad-side to the plane of the radiator, and is vertically polarized. In one embodiment, the symmetric planar radiator has an outer edge that is bilaterally symmetrical. In another embodiment, the outer edge of the symmetric planar radiator is bilaterally symmetric and a closed inner edge of the radiator that defines a void is also bilaterally symmetric.

Abstract: The present invention is directed to a monopole/dipole asymmetric radiator structure that includes an asymmetric planar radiator. When the asymmetric is part of an operative monopole or dipole antenna, the antenna exhibits a wide or broad bandwidth, a VSWR of less than about 3:1, a relatively constant gain perpendicular or broad-side to the plane of the radiator, and is vertically polarized. In one embodiment, asymmetric planar radiator has an outer edge that is bilaterally asymmetrical. In another embodiment, the outer edge of the asymmetric planar radiator is symmetric and a closed inner edge of the radiator that defines a void is bilaterally asymmetric.

Abstract: A low-profile lens element for steering a beam is provided. Specifically, the low-profile lens element is mechanically rotatable such that a beam can be steered in any direction within three-dimensional space. The lens element may include a number of discrete portions for differentially delaying adjacent discrete portions of a beam in order to effect beam steering. These discrete portions may vary in width. In addition, multiple lens elements may be provided.

Abstract: Air loaded stripline assemblies and methods for providing same are disclosed. The air loaded stripline assembly includes circuit board layers interconnected to one another. A layer containing a conductive trace forming a stripline is connected to spacer layers. The spacer layers include voids or relieved areas, that define cavities adjacent areas of the stripline layer on which the stripline is formed. Ground plane layers are interconnected to the spacer layers, bounding the cavities. The air loaded stripline assembly can additionally incorporate conductive vias for electrically interconnecting the stripline to other components or assemblies. The air loaded stripline assembly can be formed using conventional printed circuit board techniques.

Abstract: A passive proximity detection system and method are provided. A transmitted signal, such as a communication signal, is sampled and placed in memory. A version of the transmitted signal, reflected by a target in the vicinity of the transmitting antenna, is sampled and compared to the stored reference sample. Correlation between the reference and reflected samples indicates the presence of a target in the vicinity of the transmitting antenna. Processing of the signals can include frequency shifts to account for Doppler shifts in the reflected energy as a result of a non-zero relative radial velocity of the target. Multiple antennas for receiving reflected energy can be provided to enhance the coverage area of the system, and/or to provide information regarding the relative location of a target. In addition, signals from multiple transmitting antennas can be used as sources of energy for probing the vicinity of those antennas for targets.

Abstract: Method and apparatus for minimizing antenna backside signal response and ambiguity in low frequency applications, particularly low frequency synthetic aperture radar (SAR). Various time delay elements are selectably switched into the signal path so as to cause a null to be placed in the antenna response pattern in the direction of undesired radar returns. The means for selectably switching may be dithered so as to introduce modulation onto the undesired radar return to aid in the discrimination and removal of the undesired radar return from the SAR image during post processing.

Abstract: Mitigation of the effects of multipath signals is provided. Such mitigation can include electronically steering the main beam of a receive pattern associated with a phased array antenna away from a transmitting antenna. In addition, a phase taper is applied to groups of antenna elements to create a null in the main beam, bifurcating that beam. The multipath signal may be placed in or towards the null, while the direct path signal may be placed on one of the halves of the main beam adjacent the null, such that the signal strength of the multipath signal is attenuated as compared to the signal strength of the direct path signal.

Abstract: Method and apparatus for minimizing antenna backside signal response and ambiguity in low frequency applications, particularly low frequency synthetic aperture radar (SAR). Various time delay elements are selectably switched into the signal path so as to cause a null to be placed in the antenna response pattern in the direction of undesired radar returns. The means for selectably switching may be dithered so as to introduce modulation onto the undesired radar return to aid in the discrimination and removal of the undesired radar return from the SAR image during post processing.

Abstract: Bulk material measurement packages are described including the preferred embodiment of an automated instrument package (AIP) suited to mount on the inside ceiling of a large silo. The gimbaled AIP vertical mounting bracket rotates in an approximate 360° azimuth. An instrument housing is mounted to the vertical mounting bracket, and it rotates approximately 190° in a vertical plane. The instrument housing has at least one range finding sensor such as a scanning laser to measure the top surface contours of the bulk material. The instrument housing can also contains other sensors such as air and quality instruments including temperature, humidity, spectral recognition sensor to detect grain/material type and/or flow rate, gas detectors for sniffing off-odors/spoilage/or safety problems, and live video. Optionally grain penetrating radar (GPR), time domain reflectometry (TDR), ultrasonics, and portable sensors are taught as well as alternate packaging.

Abstract: Bulk material measurement packages are described including the preferred embodiment of an automated instrument package (AIP) suited to mount on the inside ceiling of a large silo. The gimbaled AIP vertical mounting bracket rotates in an approximate 360° azimuth. An instrument housing is mounted to the vertical mounting bracket, and it rotates approximately 190° in a vertical plane. The instrument housing has at least one range finding sensor such as a scanning laser to measure the top surface contours of the bulk material. The instrument housing can also contains other sensors such as air and quality instruments including temperature, humidity, spectral recognition sensor to detect grain/material type and/or flow rate, gas detectors for sniffing off-odors/spoilage/or safety problems, and live video. Optionally grain penetrating radar (GPR), time domain reflectometry (TDR), ultrasonics, and portable sensors are taught as well as alternate packaging.

Abstract: Method and apparatus for providing a configurable circuit are disclosed. In addition, method and apparatus for providing a phased array antenna having an integrated configurable circuit are provided. According to the present invention, at least a first component of a configurable circuit is formed on a first substrate. At least a second component of a configurable circuit is formed on at least a portion of a moveable cantilever formed from a second substrate. The first and second substrates are registered with one another to form a completed configurable circuit. According to the present invention, a configurable circuit may comprise a variable capacitor or a switch. In addition, a configurable circuit may be used in connection with phase shifting a radio frequency signal provided to an element of a phased array antenna.

Abstract: Method and apparatus for providing a configurable circuit are disclosed. In addition, method and apparatus for providing a phased array antenna having an integrated configurable circuit are provided. According to the present invention, at least a first component of a configurable circuit is formed on a first substrate. At least a second component of a configurable circuit is formed on at least a portion of a moveable cantilever formed from a second substrate. The first and second substrates are registered with one another to form a completed configurable circuit. According to the present invention, a configurable circuit may comprise a variable capacitor or a switch. In addition, a configurable circuit may be used in connection with phase shifting a radio frequency signal provided to an element of a phased array antenna.

Abstract: The present invention provides a method and apparatus for carrying signals having different frequencies in a space-deployed antenna system. When the antenna system is in a first mode, DC power, command information and RF signals (1) are multiplexed via a multiplexer, (2) propagate along a RF transmission line and (3) are appropriately demultiplexed by a demultiplexer associated with each T/R module. Similarly, when the antenna system is in a second mode, telemetry data and RF signals (1) are multiplexed via a multiplexer, (2) propagate along the RF transmission line and (3) are appropriately demultiplexed by a demultiplexer at a driver stage. By using the RF transmission lines associated with each T/R module to deliver (1) DC power, (2) command data and (3) RF signals in the first mode and to deliver (1) telemetry data and (2) RF signals in the second mode, the DC power and command/telemetry wire harnesses (and their respective conductors) may be eliminated.

Abstract: A crossed-slot antenna having a reduced number of feed components to achieve circular polarization. The present invention provides a crossed-slot antenna capable of transceiving circularly polarized radiation and having a feed network comprising a ninety degree hybrid and at least one infinite balun. In one embodiment, a transmission line is used to feed a pair of antenna patch elements, one of which acts as a local ground plane for the microstrip line, thereby defining an infinite balun. The transmission line may comprise a microstrip line, the inner conductor of a coaxial cable, or a coplanar waveguide.

Abstract: An antenna system determines the true time delay in two or more correlated signals without a priori knowledge of the time relationship between the signals and uses the determined true time relationship to achieve maximum signal combinations of received and/or transmitted signals, increased receive G/T and/or transmit EIRP. The antenna system can provide adaptive beam steering with optimal time delays for each antenna element of a phased array and can combine distinct antenna apertures to create a larger effective antenna aperture.

Abstract: The feedline connection to a microstrip antenna patch is designed to integrally include a predetermined capacitance for broadbanded operation. RLC parameters of a parallel circuit model for a specific radiator for a given feedpoint location are measured or otherwise determined. A series LC feed network is then employed and predetermined series LC parameters are chosen so as to optimize the desired bandwidth for the resulting two-stage band pass filter network. The resulting broadbanded microstrip antenna system, network may provide an operating bandwidth on the order of 30% (with less than 2:1 VSWR).

Abstract: A microstrip annular antenna structure is formed by four quarter-wavelength microstrip radiator patches arranged in a quadrant formation and having outwardly directed adjacent radiating apertures which together provide a composite annular radiating slot extending about 360.degree. of azimuth. All such radiators are fed in-phase by a single centrally located feedpoint and equal length microstrip transmission lines extending diagonally therefrom to a respective matched impedance feedpoint associated with each radiator patch structure. An extremely low profile rf antenna system results with a monopole or annular slot vertically polarized radiation pattern.