Metamaterial Bandpass Filter Based on Three-Dimensional Structure

In this paper, a tunable, broadband metamaterial (MM) bandpass filter based on three-dimensional (3D) structure was designed. It improves the out-of-band attenuation problem of the traditional planar metamaterial filters. The filter has good out-of-band attenuation and produces two transmission zeros at low and high frequencies. The transmission rates at the two transmission zeros are − 20.412 dB and − 16.705 dB, respectively. The simulated results show that the 3 dB bandwidth is 46.156 THz. In addition, due to the symmetry of the structure, it is insensitive to electromagnetic (EM) waves with different polarization. It can also adjust the working bandwidth, the transmission zero and the center frequency. In the process of adjustment, the working bandwidth remains basically unchanged, while the transmission zeros and center frequency stay linear. The structure we designed provides a great possibility for the application of metamaterial filters in optical frequency devices.