中文摘要：

提出了利用介质陶瓷和铁氧体材料构建可调型带通频率选择表面的设计思路.在C波段波导模式下通过仿真设计出高介电常数方形柱状结构,优化后使其产生宽频的负介电常数,基于等效媒质理论对该结构通阻特性进行分析研究,其传输禁带的产生途径在于介质中产生了具有类Drude谐振形式的电单极子.在相同的仿真环境下对铁氧体结构进行设计优化,调节外加偏置磁场,使铁磁谐振在相应的频点发生,产生负磁导率.利用负介电常数与负磁导率的＂双负＂特性规律,将两种结构进行组合,协同优化,使电磁谐振相互耦合,实现通带特性.C波段波导模式下的分析表明,两种结构在同一个频点电磁谐振耦合,可以实现＂双负＂通带的传输效果.在由于铁氧体的磁可调特性,通过改变外加偏置磁场,该通带可以在6—8 GHz范围内可调.对电磁场矢量分布状况和等效参数提取结果进行了数值分析研究,确定了电磁耦合的性质和形成机理,充分验证了这种方法的可行性.对该结构材料样品进行加工,并测试验证,最终实验结果与仿真结果基本一致,实现了＂双负＂通带的可调.该方法拓展了频率选择表面的设计思路,可用于设计多通带、可调谐频率选择表面.

英文摘要：

In this paper, a method of designing tunable bandpass frequency selective surface via ceramics and ferrite material is proposed. The ferromagnetic resonance frequency can be tuned when magnetic field is applied. According to this property, the center-frequencies of the pass and stop band can be adjusted. The proposed model is composed of the ceramic part and ferrite part, and CST simulation under C band waveguide condition is employed in the research. For the ceramic part, five high-permittivity rectangular blocks are included. The aim is to achieve negative permittivity in broad band. The band-pass and band-stop properties of the frequency selective surface are clarfied based on the effective medium theory. The stop band originates from a similar Drude resonant electric monopole in the medium. The part of ferrite is composed of ten rectangular blocks. By adjusting the applied magnetic field, the ferromagnetic resonance and negative permeability are obtained at corresponding frequencies. Based on the ＂double negative＂ characteristics,the two parts are combined together to realize the pass band. For instance, when the magnetic field H0 is 1700 Oe, the ferromagnetic resonance appears at a frequency of 6.778 GHz. In this case, the center frequency of the pass band is at6.758 GHz. By interacting with the electromagnetic wave, the electric resonance can take place in the ceramic blocks,and the ferromagnetic precession will appear in the ferrite blocks. The simulation results indicate that the pass band is switchable and tunable in a range of 6–8 GHz by changing the bias magnetic field. The distributions of electric and magnetic fields, and the parameters of perimittivity, permeability and impedance are obtained and discussed. Finally,the samples are fabricated and tested. The experimental results are basically consistent with the simulation results,indicating that the ＂double negative＂ passband can be adjusted via the applied magnetic field. This proposal provides a route to designing all-dielectric frequenc