基于多个圆环嵌套结构单元, 设计、加工与测试了一种对偏振无依赖以及大角度入射稳定的三波段超材料宽带带通滤波器(BPF)。仿真结果表明该滤波器存在三个通带, 中心频率分别为7.22, 10.10, 14.46 GHz, 3 dB相对带宽分别为17.5%, 20.2%和17.4%, 中心频率处透射率分别为-0.85 dB, -0.69 dB和-1.73 dB。单元结构具有旋转对称性, 使得该滤波器对电磁波偏振不敏感, 并且在入射角达到40°时, 三个波段依然维持较好的稳定性。通过监测谐振频点处的表面电流分布情况, 分析了三波段滤波的物理机理。这种带通滤波器具有多波段滤波、偏振无依赖以及大角度入射稳定等特性, 有望在多频谱成像技术、信息通信等领域发挥一定的作用。

A triple-band metamaterial broadband bandpass filter (BPF) which is independent to polarization and stable at wide-angle incidence is designed, fabricated and tested. Simulation results show that the designed BPF has three broadband passbands. The center frequencies are 7.22, 10.10 ,14.46 GHz. 3 dB relative bandwidths are 17.5%, 20.2% and 17.4%. The transmission efficiencies at center frequency are -0.85 dB, -0.69 dB and -1.73 dB, respectively. This BPF is insensitive to the electromagnetic wave polarization, because the structure is rotational symmetry. Additionally, three bands of the designed BPF can still keep stable performance, when incident angle reaches 40°. By monitoring the surface current distributions at resonant frequencies, the physical mechanism of the triple-band filtering is analyzed. The proposed triple-band metamaterial broadband BPF is hopeful to take part in multi-frequency imaging technology, information communications and other fields owing to its multi-band filtering, independent to polarization and stable at wide-angle incidence.