Antenna/Reflectometer for Electron Density measurements of the Hypersonic Plasma Sheath

The thrust of this Phase I proposal is to conduct analyses to evaluate the plasma diagnostic capability of aperture antennas mounted on a hypersonic vehicle. To this end, expected electron density profiles will be acquired, or estimated, in order to solve for the electromagnetic wave interaction with an inhomogeneous plasma, The intent of this exercise is to calculate the input admittance of specific aperture antennas. Parametric calculations will be done in order to retrieve peak plasma frequency and electron density boundary layer thickness within the flow field. Based upon these parametric calculations, a diagnostic antenna-reflectometer system will be designed for fabrication during the Phase II effort. The reflectometer unit will be designed to accommodate at least two radio frequencies. The unit will feature a solid state oscillator and a section of transmission line with multiple diode detectors designed to infer input admittance from the resultant standing wave pattern.