Inverse Design and Optimization Research of Digital Terahertz Bandpass Filters: A Study

To meet the demand for standardized design of high-performance terahertz functional devices, this paper applies intelligent inverse design methods to the design and optimization of terahertz bandpass filters. A subwavelength metasurface equivalent model is established with a digital space mapping, starting from the target function and constraint conditions of the device. Intelligent algorithms are used to explore all possible structures in the entire solution space and iteratively optimize them to the optimal structure pattern. This paper uses the established inverse design framework to design a terahertz bandpass filter with a center frequency of 0.51 THz, bandwidth of 41.5 GHz, and insertion loss of −0.1071 dB. Compared with traditional manual forward design, the inverse design method can deconstruct a bandpass filter that is narrow-band, low-insertion loss, strong out-of-band suppression, and has strong polarization stability.