NASA Technical Reports Server (NTRS) : Effective pdf

NASA Technical Reports Server (NTRS) : Effective

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Description of the Book:

This report summarizes efforts to characterize the measurement of conductive mesh and smooth surfaces using proximity measurements for a dielectric resonator. The resonator operates in the HEM11 mode and is shown to have an evanescent field behavior in the vicinity of the sample surface, raising some question to the validity of measurements requiring near normal incidence on the material. In addition, the slow radial field decay outside of the dielectric resonator validates the sensitivity to the planar supporting structure and potential radiation effects. Though these concerns become apparent along with the sensitivity to the gap between the dielectric and the material surface, the basic concept of the material measurement using dielectric resonators has been verified for useful comparison of material surface properties. The properties, particularly loss, may be obtained by monitoring the resonant frequency along with the resonator quality factor (Q), 3 dB bandwidth, or the midband transmission amplitude.

Comparison must be made to known materials to extract the desired data

• Creator/s: NASA Technical Reports Server (NTRS
• Date: 3/1/1994
• Year: 1994
• Book Topics/Themes: NASA Technical Reports Server (NTRS), DIELECTRICS, ELECTRICAL RESISTIVITY, MICROWAVE FREQUENCIES, Q FACTORS, REFLECTOR ANTENNAS, RESONANT FREQUENCIES, RESONATORS, SPACECRAFT ANTENNAS, EVANESCENCE, LOSSY MEDIA, MESH, RADIATION EFFECTS, RESONANT VIBRATION, WIRE CLOTH, Davis, William A

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