Effects of proximity of thermal shields on tri-band antenna RF performance

Robust, inexpensive, non-conductive material that can survive launch and reentry environments is needed to support the Orion antenna suite. The boost protective cover (BPC) is not optimal for RF performance, but reasonable criteria for utilizing BPC as a material are established to perform expeditious flight qualification. This paper outlines the results of this investigation. Although BPC has a moderate dielectric (<; 2) and mediocre loss tangent (~0.05), as a radome it should not be operated near an electrically resonant antenna or as a transmission media. Since BPC has a strongly anisotropic construction of significant wavelength thickness, determining a configuration that will give acceptable performance from 0.02 to 0.25 wavelength depth was evaluated. This paper summarizes the results of tests to assess the impacts of placing the BPC in front of a planar antenna.