Doubly Periodic. Dielectric Layer On The Impedance Of The Floquet Analysis Of The Patch

With the development of military technology, stealth technology has become one of the key techniques, and gradually changing the direction of development of weapons and equipment. Stealth technology refers to that goal by reducing the range of detectable features, including radar, infrared, visible light, sound, etc., to improve the weapon system's survival and penetration ability. Radar absorbing materials is a way to achieve the development of the stealth technology.Radar absorbing materials can be divided into structural radar absorbing materials and coating absorbing material for the manufacturing procedure and carrying capacity. As no-change for object's shape, easy to use and other reasons, the application of coating absorbing material is extremely broadly used. Material containing permeability or dielectric constant imaginary part can improve the bandwidth of absorbing material in a certain frequency range. Magnetic absorbing materials are usually containing with carbonyl iron or ferrite for practical applications. Such coating-absorbing materials used most commonly. Unfortunately, the absorbing band of these materials greatly depends on the coating thickness, and also the density is too high.Radar absorbing materials should in order to achieve the need of "lighter, thinner, wider, stronger" for developing new stealth material. Using the doubly periodic surface structure to improve the absorbing properties of composites is a viable approach. According to Floquet theory, the transfer matrix and so on, mathematical model of thin material with rectangular doubly periodic structure was established, and then using the method of moment to establish equations for unknown patch surface currents, the final reflectivity of the material parameters was obtained. Then the computing program according to the theoretical model was programmed.In the light of the results, we discussed the reflectivity of periodic square patch on thin substrates for doubly periodic structures, with the variation of patch size, period cell size, medium thickness, the permittivity, the surface impedance. Later, we did a similar analysis and calculation for a double layered structure. The results show that reasonably design for the dielectric layer with doubly periodic structure can expand the effective bandwidth of absorbing material. At the same time, the equal permittivity and the equal permeability was calculated for two kinds of dielectric substrates. Thus, an intuitional influence with the doubly periodic structure was shown.Through the numerical calculation study of multi-factor for frequency response characteristics of doubly periodic structures, we try to find some regularity through the result, in order to provide the necessary basis for the actual design.