Design And Research Of The Three-dimensional Metamaterial Absorbing Structure

Electromagnetic waves play an important role in our daily life and national defense and security. However, there are some negative effects, for example, the signals of mobile phone will interfere with other electronic devices, the enemis' radar will reduce the survival rate of our military targets and so on. Therefore, the electromagnetic wave absorption material or structure has great military and commercial value. A good electromagnetic wave absorption materials or structures should have excellent absorbing performance, light weight, low profile, high strength, and can adapt to all kinds of application environment, etc. Salisbury screen is a typical absorber which is shown as a narrowband resonance absorber. Only when the thickness of the medium is integral multiple of the wavelength in medium, the excitation field can form stable standing wave in medium, which make energy effective resides within the dielectric layer and loss. This makes the design of the low frequency absorption materials in trouble for it can not meet the claim to be thin and light. Its narrow band features can be optimized by certain means, such as to be made into multi-layer structure, which may result in a rough structure.Circuit analogue absorber is another widely used absorbing structure that has some excellent features such as light weight, voltage, temperature, can be suitable for all kinds of extreme environment, etc. The familiar circuit analogue absorber can be realized by a periodic stack of a number of small printed circuit boards (PCB). Particular frequency absorption can be achieved by changing the geometric shape of conductive materials to adjust the resonance frequency of the circuit structure. In the case of a single layer the bandwidth is narrow while a multilayer structure will make the whole structure bloated to carry out.In this paper, two kinds of circuit analogue absorber based on three-dimensional periodic array of microstrip and parallel-plate waveguide are studied. Optimization algorithm is used to optimize the absorbing bandwidth and absorbing structure design under the dual polarization is also presented in this paper.The main research work and conclusions are as follows:1. Wideband microwave absorber based on a three-dimensional periodic array of microstrip lines. We research on filed pattern analysis, impedance matching, and the design method of absorbing structure, based on which we carry out a series of experiment whose conclusion is consistent with previous theory.2. Another absorber based on a three-dimensional periodic array of parallel-plate waveguide. As similar to the above analysis, we research on filed pattern analysis, impedance matching, and the design method. The absorbing performance is verified from the experiment.3. A non-polarization three-dimensional absorber based on parallel-plate waveguide is presented. The PSO optimization algorithm is used in designing polarization insensitive three-dimensional absorbing structure. The final design possesses a bandwidth of 2-5GHz.4.Particle swarm optimization (pso) algorithm in the application of three-dimensional absorbing structure parameters optimization is shown.(1). The introduction of particle swarm optimization (pso) algorithm and application in the engineering design.(2). Particle swarm optimization (pso) algorithm in the application of three-dimensional absorbing structure parameters optimization under the different requirements.(3) The application of particle swarm optimization (pso) algorithm to reduce the thickness of the structure.