Design and measurement of radiowave transmissive thermal control mirror

This paper describes a new flexible thermal control mirror: controlled optical surface films. Controlled optical surface film exhibits high reflectivity to solar radiation, high infrared emissivity, and high transmittance to radio waves. The target of radiowave transmittance is Ge-coated Kapton, which is used on antenna covers; the target of thermooptical properties is the optical solar reflector. Controlled optical surface film controls spectral reflectance and absorptance in wavelengths ranging from 0.26 to 100 μm with a dielectric multilayer. This multilayer is designed using a genetic algorithm method. The solar absorptance of the latest controlled optical surface film is 0.09, and its total hemispherical emittance is 0.77 at 300 K. These properties are similar to those of the optical solar reflector. In addition, there is little radiowave attenuation in this controlled optical surface film, and its radiowave transmittance is similar to that of Ge-coated Kapton.