Frequency tunable terahertz filter based on dual layered split-ring resonator array

Terahertz frequency tunable filter based on the dual layered split-ring resonator (SRR) array was fabricated on flexible polyimide film using conventional photolithography techniques. The fabricated SRR array was measured by terahertz time-domain spectroscopy (THz-TDS) and compared with the simulation data. We found that the center frequency could be controlled from 1.04 to 1.65 THz by the dipole coupling effect between upper and lower SRR layers. The bandwidth of the fabricated filter is also confirmed to be tuned validly ranging from 1.04 to 1.72 THz. By using the extracted field distribution, we verified that the localized field enhancement could be manipulated by changing the coupling distance between adjacent layers. (C) 2014 The Japan Society of Applied Physics