Abstract:Tunable band-pass filter is one of the indispensable components in the Internet of Things, satellite communication, smart antennas. According to the current application requirements for miniaturization, low cost and high integration of tunable bandpass filters, a design method of tunable bandpass filters based on liquid crystal (LC) materials was proposed in this paper. Firstly, the epsilon near zero (ENZ) metamaterial unit based on microstrip transmission line structures was designed, and the narrow-band filtering function was effectively realized by the narrow-channel tunneling effect of ENZ metamaterials. On the basis of this, the bandpass filter consisted of three ENZ metamaterial units was designed to realize better filtering performance on this basis. Secondly, LC materials were introduced into the tunneling channel of ENZ metamaterials. The effective regulation of the band-pass filtering characteristics was finally realized by tuning the dielectric performance of LC materials with external driving voltages. Finally, the full-wave numerical simulation results showed that the proposed ENZ metamaterial-based LC bandpass filter could achieve continuous regulation of the center frequency from 15.88 GHz to 16.73 GHz, which verified the effectiveness of the above design method.
