Abstract: An antenna system includes a plurality of antenna elements arranged in an array having a plurality of array elements. Each antenna element has a radiator extending from a radiator feed end to a radiator terminal end, where a first straight-line distance from the radiator feed end to the radiator terminal end is less than ?/4, ? being a longest wavelength of a bandwidth of the antenna element. Each antenna element also includes a counterpoise extending from a counterpoise feed end to a counterpoise terminal end, where a second straight-line distance from the counterpoise feed end to the counterpoise terminal end is less than ?/4. The counterpoise feed end is spaced apart from the radiator feed end. The radiator and the counterpoise diverge at an acute angle from an area encompassing the radiator feed end and the counterpoise feed end.

Abstract: A pair of radar nodes, each with full azimuthal coverage, cooperate to identify the position of an object without explicit measurements of the object's azimuthal coordinate. A first radar node, operating within a first azimuth field of view (FOV), measures a first elevation angle and a first slant range of the object. A second radar node, operating within a second azimuth FOV, measures a second elevation angle and a second slant range of the object. The second radar node transmits the data to the first radar node, which identifies, based on the first and second azimuth FOVs, an object half space within which the object is located. The first radar node then calculates the position of the object without an ambiguous solution. Alternatively, the first radar uses the first and second azimuth FOVs to identify and reject the ambiguous solution.

Abstract: A method for controlling an antenna array includes determining, based on a beamstate, an initial weight vector of excitations. The initial weight vector is transformed into an active-impedance vector. When the modulus of any element of the active-impedance vector exceeds a threshold, the initial weight vector is unsafe. In this case, a substitute weight vector is identified such that (i) the initial and substitute weight vectors have a similarity measure that exceeds a similarity threshold and (ii) the substitute weight vector is safe. The antenna array may then be driven according to the substitute weight vector to emit radiation having a radiation pattern that approximates that of the beamstate. The substitute weight vector may be found by searching a library of safe weight vectors or by adjusting the excitations of the initial weight vector until a safe alternative is found.

Abstract: An antenna element is provided that is adapted to provide a more consistent horizontally polarized signal. In one embodiment, a radiator and counterpoise are provided with the counterpoise being disposed between the radiator and a ground plane in use. The feed location for feeding the radiator and the counterpoise is significantly spaced from the ground plane in use and the radiator and counterpoise diverge relative to this feed location.

Abstract: The invention is directed to an antenna structure for producing a horizontally polarized beam. In one embodiment, the antenna structure includes a first quarter-wave patch antenna and a second quarter-wave patch antenna that are positioned such that the ground planes of the patch antennas or a ground plane shared by the patch antennas is disposed between the patches of the two antennas and the shorting structures associated with the antennas are substantially aligned. In operation, the antenna structure is capable of processing an omni-directional, horizontally polarized beam.

Abstract: The invention is directed to a broadband, low-profile antenna structure that in one embodiment includes a compound radiator and a ground plane. The compound radiator is comprised of a dipole radiator portion and a Vivaldi radiator portion that is electrically connected to the dipole radiator portion. In operation, the dipole radiator portion operates in the lower end of the bandwidth and the Vivaldi radiator portion operates in the upper end of the bandwidth.

Abstract: A broadband antenna system is disclosed. The antenna system relates to a cylindrical structure, wherein the feed region comprises segmented radiators with tapered feed points, distributed around the circumference of the structure, and a balun that is co-planar with the cylindrical structure. This allows a plurality of feed lines, cables, piping, or other structures to be run through the center of the antenna without interfering with the performance of the antenna system. Segmentation of the radiators permits the integration of a corporate feed network, suppresses overmoding, and permits operation without the need for a ground plane. The invention further relates to a stacked broadband antenna system wherein additional antenna elements or devices may be stacked collinearly on the antenna structure and operated via the plurality of feed lines or other structures. The overall system thus provides a wide range of transmitting, receiving, sensing and other capabilities over a virtually infinite bandwidth.

Abstract: A radar system having orthogonal antenna apertures is disclosed. The invention further relates to an antenna system wherein the orthogonal apertures comprise at least one transmit aperture and at least one receive aperture. The cross-product of the transmit and receive apertures provides a narrow spot beam and resulting high resolution image. An embodiment of the invention discloses orthogonal linear arrays, comprising at least one electronically scanned transmit linear array and at least one electronically scanned receive linear array. The design of this orthogonal linear array system produces comparable performance, clutter and sidelobe structure at a fraction of the cost of conventional 2D filled array antenna systems.

Abstract: A broadband antenna system is disclosed. The antenna system relates to a cylindrical structure, wherein the feed region comprises segmented radiators with tapered feed points, distributed around the circumference of the structure, and a balun that is co-planar with the cylindrical structure. This allows a plurality of feed lines, cables, piping, or other structures to be run through the center of the antenna without interfering with the performance of the antenna system. Segmentation of the radiators permits the integration of a corporate feed network, suppresses overmoding and permits operation without the need for a ground plane. The invention further relates to a stacked broadband antenna system wherein additional antenna elements or devices may be stacked collinearly on the antenna structure and operated via the plurality of feed lines or other structures. The overall system thus provides a wide range of transmitting, receiving, sensing and other capabilities over a virtually infinite bandwidth.

Abstract: A broadband antenna system is disclosed. The antenna system relates to a modified conical structure, wherein the feed region of the cone is cut away to form a hollow “coneless” cylinder, and the distribution of one or more tapered feed points around the circumference of the cylinder allows a plurality of feed lines, cables, piping, or other structures to be run through the center of the antenna without interfering with the performance of the antenna system. The invention further relates to a stacked broadband antenna system wherein additional coneless elements, as well as other types of antennas or devices, may be stacked collinearly on, or disposed coaxially to, the cylindrical antenna structure, and fed, powered or operated via the plurality of feed lines, cables, piping or other structures. The overall system may thus provide a wide range of transmitting, receiving, sensing and other capabilities.

Abstract: A radar system having orthogonal antenna apertures is disclosed. The invention further relates to an antenna system wherein the orthogonal apertures comprise at least one transmit aperture and at least one receive aperture. The cross-product of the transmit and receive apertures provides a narrow spot beam and resulting high resolution image. An embodiment of the invention discloses orthogonal linear arrays, comprising at least one electronically scanned transmit linear array and at least one electronically scanned receive linear array. The design of this orthogonal linear array system produces comparable performance, clutter and sidelobe structure at a fraction of the cost of conventional 2D filled array antenna systems.

Abstract: A broadband antenna system is disclosed. The antenna system relates to a modified conical structure, wherein the feed region of the cone is cut away to form a hollow “coneless” cylinder, and the distribution of one or more tapered feed points around the circumference of the cylinder allows a plurality of feed lines, cables, piping, or other structures to be run through the center of the antenna without interfering with the performance of the antenna system. The invention further relates to a stacked broadband antenna system wherein additional coneless elements, as well as other types of antennas or devices, may be stacked collinearly on, or disposed coaxially to, the cylindrical antenna structure, and fed, powered or operated via the plurality of feed lines, cables, piping or other structures. The overall system may thus provide a wide range of transmitting, receiving, sensing and other capabilities.

Abstract: An ultra-broadband antenna system is disclosed. The antenna system is a single tubular antenna structure comprising an asymmetrical dipole fed with a biconical dipole. The biconical dipole covers the high frequency spectrum, while the asymmetrical dipole covers intermediate frequencies. The invention further relates to a combination of the two dipole structures such that together they act as a monopole to cover the low frequency spectrum. A first RF connector attaches to the asymmetrical dipole and the biconical dipole, and a second RF connector excites the combination of the two dipoles as one large monopole. A choke minimizes interference between the asymmetrical/biconical dipoles and the monopole. The resulting frequency span is greater than 500:1, providing operation over the range of 20 MHz to 10 GHz.

Abstract: An ultra-broadband antenna system is disclosed. The antenna system is a single tubular antenna structure comprising an asymmetrical dipole fed with a biconical dipole. The biconical dipole covers the high frequency spectrum, while the asymmetrical dipole covers intermediate frequencies. The invention further relates to a combination of the two dipole structures such that together they act as a monopole to cover the low frequency spectrum. A first RF connector attaches to the asymmetrical dipole and the biconical dipole, and a second RF connector excites the combination of the two dipoles as one large monopole. A choke minimizes interference between the asymmetrical/biconical dipoles and the monopole. The resulting frequency span is greater than 500:1, providing operation over the range of 20 MHz to 10 GHz.

Abstract: Dielectric materials having modified dielectric constants and methods for modifying the dielectric constant of a dielectric material are provided. Generally, the dielectric constant of a dielectric material is modified by providing relieved portions within the dielectric material. The relieved portions may comprise holes formed in the dielectric material. In connection with dielectric material that is incorporated into an antenna apparatus, the size and/or arrangement of holes or other relieved portions in the dielectric material can be determined with reference to the operating wavelengths of the antenna apparatus.

Abstract: The present invention provides an antenna system for use in determining N unknown parameter values relating to an object located in the vicinity of the system. One embodiment of the system includes a body with a longitudinal axis and a plane that is substantially perpendicular to the roll axis. The system further includes an antenna array comprised of a plurality of elements, each of which is located in a ring in the noted plane and separated from each of the other elements by less than 180° relative to the longitudinal axis. Also included in the improved antenna system is a beamformer for producing N+1 beams and a device for using the N+1 beams to determine N values associated with the object.

Abstract: The present invention provides an improved antenna system that, in one embodiment, includes an antenna array comprised of a plurality of elements, each of which is capable of providing a signal. Also included in the improved antenna system is, a multi-beam beamformer for producing two spatially independent overlapping beams from the signals provided by two different subsets of the antenna array. The phase of the two beams is compared to realize an interferometer that can provide high or fine resolution data on the position of an object relative to the antenna system. The amplitude of the two beams can also be compared to obtain coarse data on the position of the object. The beamformer includes a switching network for selecting which elements of the antenna array form the two subsets. This permits, for example, the position of the beams to moved, the baseline of the two beams to be varied, and/or the beam width of the beams to be altered.

Abstract: A radio frequency reconfigurable lens is provided. In particular, a lens comprising at least two opposed frequency selective surface sheets is provided. A relative phase shift may be imparted to an incident radio frequency wave by varying the distance between at least some of the unit cells of a first of the FSS sheets and adjacent unit cells on a second of the FSS sheets. In order to provide a desired phase taper across the width of a lens, and/or to provide different phase shift amounts, pairs of FSS surfaces having controllable columns or rows can be cascaded together. According to an additional aspect of the present invention, radio frequency waves can be scanned by cascading multiple tunable stages. The present invention also provides a radio frequency shutter.

Abstract: A dual band coplanar microstrip interlaced array antenna is provided. The antenna may be confined to a relatively small area, while providing dual band operation with no or minimal grating lobes and losses. According to the present invention, first and second arrays are interlaced with one another to minimize the surface area of the antenna. A maximum spacing between array elements is selected based on the operating wavelengths and scan range for each of the arrays. A first dielectric constant of a material underlying elements of the first array is calculated from the selected element spacing and the operating wavelength of the first array. A second dielectric constant of a material underlying elements of the second array is calculated from the first dielectric constant and the operating frequencies of the first and second arrays. The present invention provides a dual band coplanar microstrip interlaced array antenna capable of efficient operation at two center frequencies.

Abstract: A dual band coplanar microstrip interlaced array antenna is provided. The antenna may be confined to a relatively small area, while providing dual band operation with no or minimal grating lobes and losses. According to the present invention, first and second arrays are interlaced with one another to minimize the surface area of the antenna. A maximum spacing between array elements is selected based on the operating wavelengths and scan range for each of the arrays. A first dielectric constant of a material underlying elements of the first array is calculated from the selected element spacing and the operating wavelength of the first array. A second dielectric constant of a material underlying elements of the second array is calculated from the first dielectric constant and the operating frequencies of the first and second arrays. The present invention provides a dual band coplanar microstrip interlaced array antenna capable of efficient operation at two center frequencies.