Adaptive antenna structures

Unwanted RFI is a growing concern due to the ever expanding RF world around us. Not only are the number of RFI sources increasing, so too is the frequency usage across the RF spectrum. As a result, RF systems like the AFSCN are expected to become more susceptible to disruptions in coverage and service. Additionally, these systems must maintain a small RF footprint and not contribute to the problem either. Two approaches must be considered to rectify this situation. Firstly, the AFSCN antenna sidelobe levels must be minimized so as to spatially reject unwanted stray signals. Secondly, a variable beamwidth capability must be added to improve satellite search time and dynamically optimize the link with minimal RFI on transmission or reception. The proposed Phase I program applies diffraction suppression and reflector illumination techniques to achieve a comprehensive cost effective solution to the AFSCN RFI problem. Specifically, the AFSCN antenna will be modeled and subsequently used to optimize absorber treatments for sidelobe reduction as well as optimize reconfigurable surfaces to augment the feed for variable beamwidth capability. Prototypes of an absorber and reconfigurable surface will be designed, fabricated and tested to demonstrate performance and feasibility of the technology.