Electrical Characterization of Fiber-Reinforced Composites for Mast and Radome Applications.
NAVAL SURFACE WARFARE CENTER CARDEROCK DIV BETHESDA MD
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This work was undertaken to assess the accuracy and precision achievable by using an open-ended coaxial probe in conjunction with an automated network analyzer for the characterization of the microwave dielectric properties of composites for antenna radomes. Reported herein are the influence of material thickness, surface roughness, and instrument calibration on this technique which requires only one-sided access to the material. The unknown dielectric properties of several glass fiber reinforced polymers were evaluated after the measurement system demonstrated satisfactory results on well known materials like Teflon and fused quartz. Limited low frequency testing 40 MHz was also done on selected composites with electrodes attached for capacitance and loss measurement, yielding results in substantial agreement with those in the microwave regime. It is concluded that the microwave probe technique should be applied only for materials of substantial thickness and smooth surface conditions. Because of the need for rigid fixturing, this technique is not recommended for routine applications in the field. MM
- Laminates and Composite Materials
- Electricity and Magnetism