Abstract

Characterization of Fiberglass for Use in Antenna Fairings
Elizabeth Murray Dr. Rick Hale and Emily Arnold, Center for Remote Sensing of Ice Sheets, the University of Kansas, Lawrence, KS 66045

The Center for Remote Sensing of Ice Sheets (CReSIS) uses a Twin Otter aircraft to fly over ice sheets in Greenland and Antarctica and detect ice thickness via radar.  The externally mounted radar antennas must be covered with fiberglass fairings to protect the instruments from the environment and minimize the effect of flutter caused by the motion of the aircraft.  The purpose of this project is to characterize four types of fiberglass—E glass (“Electrical” glass), S glass (“Structural” glass), S2 glass, and preimpregnated S2 glass with variable thicknesses ranging from 0.05 to 0.25 inch.  The results of this project will lead to a better understanding of how these glasses may be used in antenna fairings at frequencies in the range of 2 to 18 GHz.  The signal delay and attenuation were measured using two antennas connected to a vector network analyzer and separated by a test panel of the respective glass.  From these measurements the dielectric constant and loss tangent were calculated.  Results show that E glass and S2 glass are likely the best suited for use in the fairings due to small delays and low attenuation, and that the ratio of resin to hardener used in fabrication has little effect on the dielectric properties of the finished composite.  However, data above 10 GHz was deemed unreliable and inconclusive for all glasses; retesting with a higher resolution timer may yield better results.