Patents by Inventor Ajay I. Sreenivas
Ajay I. Sreenivas has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 7026995Abstract: 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.Type: GrantFiled: January 23, 2004Date of Patent: April 11, 2006Assignee: Ball Aerospace & Technologies Corp.Inventors: Ajay I. Sreenivas, Farzin Lalezari
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Patent number: 6795020Abstract: 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.Type: GrantFiled: January 24, 2002Date of Patent: September 21, 2004Assignee: Ball Aerospace and Technologies Corp.Inventors: Ajay I. Sreenivas, Farzin Lalezari
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Publication number: 20040155820Abstract: 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.Type: ApplicationFiled: January 23, 2004Publication date: August 12, 2004Inventors: Ajay I. Sreenivas, Farzin Lalezari
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Publication number: 20030137456Abstract: 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.Type: ApplicationFiled: January 24, 2002Publication date: July 24, 2003Inventors: Ajay I. Sreenivas, Farzin Lalezari
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Patent number: 5838282Abstract: The present invention relates to an antenna system which is capable of multiband operation from a single antenna aperture. The system provides a high degree of design freedom for achieving desired antenna pattern shapes for all relevant frequency bands. The system achieves this pattern shaping ability by utilizing a unique array configuration which is highly adaptable. The array configuration may include a center array element for each of the relevant frequency bands. In one embodiment of the present invention, a dual frequency band antenna is provided which includes a stacked patch element as the center element in a first frequency band and a crossed dipole element, mounted on top of the stacked patch, as the center element in the second frequency band.Type: GrantFiled: March 22, 1996Date of Patent: November 17, 1998Assignee: Ball Aerospace and Technologies Corp.Inventors: Farzin Lalezari, J. Mark Rogers, Ajay I. Sreenivas
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Patent number: 5821908Abstract: The invention relates to an antenna system which is capable of producing multiple, high-gain, independently steerable antenna beams from a single antenna aperture. The system accomplishes this, in part, by utilizing a separate phased array antenna as the feed element of a spherical lens for each desired beam. In this fashion, the beam(s) produced by the antenna system can each be electronically steered (independently of the other beams, if any) and physical movement of the feed element(s) is not required. The invention may also use multiple spherical lenses, wherein each lens includes at least one phased array feed.Type: GrantFiled: March 22, 1996Date of Patent: October 13, 1998Assignee: Ball Aerospace and Technologies Corp.Inventor: Ajay I. Sreenivas
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Patent number: 5382959Abstract: An efficient, lightweight, broadband antenna, having high quality circular polarization capabilities, is disclosed for use in a variety of applications. In one embodiment, signals are fed to, or received by, an array of electromagnetically coupled patch pairs arranged in sequential rotation by an interconnect network which is coplanar with the coupling patches of the patch pairs. The interconnect network includes phase transmission line means, the lengths of which are preselected to provide the desired phase shifting among the coupling patches. The complexity of the array and the space required are thus reduced. In one described embodiment, two such arrays are employed, each having four patch pairs. The two arrays are arranged in sequential rotation to provide normalization of the circularly polarized transmitted or received beam. In another embodiment, a lightweight material having a dielectric constant less than about 1.Type: GrantFiled: April 10, 1992Date of Patent: January 17, 1995Assignee: Ball CorporationInventors: Todd A. Pett, Steven C. Olson, Ajay I. Sreenivas
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Patent number: 5231406Abstract: A broadband, circular polarization antenna is disclosed for use on a satellite. In one embodiment, signals are fed to, or received by, an array of electromagnetically coupled patch pairs arranged in sequential rotation by an interconnect network which is coplanar with the coupling patches of the patch pairs. The interconnect network includes phase transmission line means, the lengths of which are preselected to provide the desired phase shifting among the coupling patches. The complexity of the array and the space required are thus reduced. In the described embodiment, two such arrays are employed, each having four patch pairs. The two arrays are arranged in sequential rotation to provide normalization of the circularly polarized transmitted or received beam.Type: GrantFiled: April 5, 1991Date of Patent: July 27, 1993Assignee: Ball CorporationInventor: Ajay I. Sreenivas