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Full-Text Articles in Engineering
Ultra-Wideband True-Time-Delay Beamforming Networks In A Compact Package, Chris Merola
Ultra-Wideband True-Time-Delay Beamforming Networks In A Compact Package, Chris Merola
Doctoral Dissertations
The push for commercial technologies such as 5G Massive MIMO, and consumer broadband internet via low-earth-orbit satellite, drive a need for low cost phased array antenna technologies. A major obstacle in bringing this technology to market is the cost and complexity of the phased array antenna aperture and the required beamforming or multi-beamforming network. This dissertation presents an efficient, reliable, low-cost and mass-manufacturable multi-beamforming network solution. In accomplishing this, a new class of cavity-based, true-time delay multi-beamformer was devised and investigated. Rotman lens optics are implemented for broadband and low phase-error response. The presented topology offers reduction in size and …
Anti-Jam Gps Controlled Reception Pattern Antennas For Man-Portable Applications, Jeffrey A. Maloney
Anti-Jam Gps Controlled Reception Pattern Antennas For Man-Portable Applications, Jeffrey A. Maloney
Doctoral Dissertations
Military GPS receivers provide crucial information to soldiers in the field, however, the performance of these devices is degraded by in band RF interference, making GPS susceptible to jamming. Anti-jam techniques for aircraft and vehicular platforms have been developed, but at present there is no system for dismounted soldiers. There is a need for an anti-jam system which meets the demands of a dismounted soldier and conforms to the size, weight, and power requirements of a portable device. A controlled reception pattern antenna, or CRPA, is a potential solution for jammer mitigation. These devices work by steering reception pattern nulls …
Bandwidth Bounds Of Infinite Planar Array Elements, Hsieh-Chi Chang
Bandwidth Bounds Of Infinite Planar Array Elements, Hsieh-Chi Chang
Doctoral Dissertations
For elements of an infinite planar phased array in free space and an infinite conductor-backed free standing planar phased array, fundamental bandwidth bounds are derived from the optical theorem for periodic scatterers. The bounds are based on Gustafsson’s theory of fundamental bandwidth limits for electrically small antennas of arbitrary shape, but extended to periodic configurations. The element bandwidth bound is found to be a function of the strengths of the induced static dipole moments in constant background fields as well as the unit-cell dimensions and the scan angle. Explicit bandwidth bound expressions are found for narrowband and ultrawideband array cases. …