| Summary: | 碩士 === 國立交通大學 === 機械工程系所 === 101 === Reflector surfaces on satellite antennas deserve research, since its electrical characteristics affect communication quality. This study deals with foldable reflectors. Kapton, as a substrate material, is sputtered with a thin layer of Au. The main concern of this research is the film resistance of the reflecting surface and the appearance of the coating layer, because these factors are highly related to electrical characteristic. When the electrical resistance of film increases rapidly and the coating occurs damage, the accuracy of the reflector and the reflection performance of electromagnetic wave do not have enough reliability anymore. Experimental results show that the electrical resistance of film will increase after the thin film has been bent several times. These results are caused by plastic deformations because the thin film has exceeded its elastic limit 205 MPa. The residual strain caused by plastic deformations leads to changes in cross-sectional shape. Additionally, the damages on the surface can also be another reason, such as cracks, delamination and wrinkles. This study simulates the behavior of satellite reflectors to observe the effects on the coating layer by measuring the variation of electrical resistance and scanning electron microscope images by repeated bending tests. Experimental results show that a crease obviously appears on the polymer substrate. However, fractures are not found on the surface of coated metal because of excellent ductility.
|
|---|
