Study On Design And Process Of The Thick-screen Frequency Selective Surface

Frequency selective surface, for short FSS, is a kind of particular structure that have many elements of two-dimensional periodic array. Its transmision performance and reflection performance represent have different function as diverse frequency of incidence wave. It is able to adjust and control transmision power of electromagnetic wave. To radar radome made of FSS technology, its radar cross section can be decreased effectively. In recent years, it has been paid attention by international communuity already because of a great deal of research achievement and rapid development of engineering applications.Thick-screen FSS is proposed, based on thin-screen FSS. It is a new type structure, unlike thin-screen FSS. Because metallic screen thickness thickened, this is equivalent to add many waveguides on thin-screen FSS. The result is that forward waves as waveguide mode are transitted when electromagnetic waves on thick-screen FSS pass through waveguides. Because of different transmission ways, thick-screen FSS and thin-screen FSS have different transmission characteristics. Besides, thick-screen FSS has high quality factor and engineering applications excellence to the curved radar radome. Therefore, it has enormously practical value.The paper has researched theories on by moment method, and deduced an important parameter transmission characteristics——transmission coefficient. According to thick-screen FSS's theories, the paper designed a thick-screen FSS with cicle-hole elements and simulated transmission characteristics of thick-screen FSS as changing multi-parameter including metallic screen thickness, element size, element spacing, incidence angle and dielectric material. After testing three metallic screen sample of thick-screen FSS and comparing with foregoing simulating results, it can be seen that center frequency and bandwidth have deviation a little, derived from processing error, measurement error, calculation error. By testing metallic screen samples with different precision in microwave dark room, it can be seen that processing quality has effect on transmission characteristics of thick-screen FSS.Aim to research thick-screen is about its curved type application. Due to how to select waveguide element on curved thick-screen, the paper has investigated transmission characteristics of thick-screen FSS having three elements with different shape(Y-hole element, cross-hole element, circle-hole element). By comparing testing data, it can be draw a conclusion that Y-hole-shape element has better transmission characteristics than other element under two polarization wave and a large-angle incidence wave. Therefore, Y-hole-element is preferred to curved thick-screen FSS.