Electrical and Computer Engineering ETDs

Publication Date

7-12-2014

Abstract

The study of Solar Microwave Bursts (SMB's) emanating from the sun is important from several perspectives. SMB's are well correlated to Coronal Mass Ejections (CME's) and therefore can provide insight into the physics of the sun. SMB's and CME's can interfere with microwave communication systems such as cell phones, satellites, and radar, and can adversely affect the accuracy of the Global Positioning System. Furthermore, CME's can be hazardous to individuals and equipment in earth orbit as well as causing power grid blackouts. The rapid detection of SMB's and their subsequent effect on space weather is a key element of responsibility of the United States Air Force (USAF). Identification of the source eliminates the possibility of intentional jamming or a systems failure. When such a determination is made, warnings can be issued so that measures can be taken such as using different communication frequencies or modes, or to place satellites in a safe mode. Currently the USAF operates the Radio Solar Telescope Network (RSTN) consisting of three parabolic dish antennas each at four locations to continuously observe the sun in the microwave spectrum. The 2.4m RSTN dishes have feeds that are single polarization at four discrete frequencies between 1.4 and 8.8GHz. Expanding the capability of these existing dishes with a single ultrawideband feed to cover 1-10GHz would improve observations, while adding a dual polarization capability could facilitate improved monitoring should there be future developments in spectrum usage. A feed with folded diamond-shaped elements in a damped cavity has been designed and constructed, funded under contract FA9453-09-C-0309 from the USAF Solar Disturbance Prediction Program, with a simulated bandwidth of 0.9 - 12 GHz. Subsequent characterization from 2 - 8 GHz showed good correlation between simulation and measurement, and that the feed meets virtually all performance specifications that were tested.

Keywords

ultrawideband, antenna, dual-polarization, parabolic

Sponsors

Air Force Research Laboratory

Document Type

Dissertation

Language

English

Degree Name

Electrical Engineering

Level of Degree

Doctoral

Department Name

Electrical and Computer Engineering

First Advisor

Christodoulou, Christos

Second Advisor

Gilmore, Mark

First Committee Member (Chair)

Barbin, Silvio

Second Committee Member

Matthews, John

Third Committee Member

White, Stephen

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