The invention provides a kind of frame structure for radiator fan. The antenna system has a dielectric member configured to receive the beam output from the emerging area and to focus the beam in an elevation plane perpendicular to a planar face of the cylindrical electromagnetic lens. As a result, the sensor chip capable of taking out the surface enhanced Raman scattering to thereby detect the substance with high sensitivity can be realized. In this invention, a primary pull chord is placed near the nip point, inserted through guides, and linked to one or more secondary longitudinal pull chord. The coating may be applied as a single layer as a multi-layer coating to enhance the performance of the coating as the ceramic matrix is formed or infiltrated from precursor materials into a preform of the ceramic fibers.