Terahertz wide-angle metamaterial absorber fabricated by printed circuit board technique

Abstract

A wide-angle terahertz metamaterial absorber is designed, fabricated, and measured. The resonant structure on the top layer of the absorber consists of two metal crosses with different sizes. The wider and higher absorption is achieved when compared with the structures that only consist of a large or small cross under different incident angles. Physical mechanisms of the absorption are clarified by their electric field distributions. The influence of the permittivity and the loss tangent of the dielectric on the absorptions are also investigated. The terahertz band sample was developed based on a double-faced copper dielectric plate using the conventional printed circuit board (PCB) technique. This saves time and allows for low cost and large-area fabrication as an alternative to the expensive conventional lithography method. The reflection spectra of the sample at oblique incidence are directly obtained using a vector network analyzer in conjunction with a quasi-optical test bench, which is used instead of the most common Fourier Transform Infrared spectrometry or Terahertz (THz) time-domain spectroscopy method in the terahertz band. The measured results are in good agreement with those of the simulation. The proposed terahertz metamaterial absorber will be crucial in the implementation of future terahertz sensors, THz communication systems, and other emerging THz technologies.