Characterization of substrate material using complementary split ring resonators at terahertz frequencies

This paper presents an approach of characterization of substrate material using complementary split ring resonator (CSRR). Frequency selective surfaces made from CSRR are excited with free space radiation. The dielectric properties of substrate material can be extracted from resonant frequencies and transmission loss at resonant frequencies. In order to verify the proposed method, the complex permittivity of Silicon substrate is measured from 110GHz to 180GHz by using backward-wave oscillator (BWO) spectrometers. And the measurement results show that the dielectric properties of Silicon substrate remain almost the same as that provided by semiconductor foundry at microwave frequencies.