Research Of The Polarization Insensitivity In Terahertz Filters

Two polarization insensitivity square split ring resonators, a polarization insensitivity double-split ring resonator and a polarization insensitivity triple-split ring resonator have been designed, fabricated and characterized. Besides, a complementary split ring resonator dual narrow band in terahertz have been designed, fabricated and characterized in this paper.1. By the investigation of the influence of asymmetric arm width in typical SSRR, the variation of the arm width enabled a blue shift of the resonant frequency for the 0° polarized wave and a red shift of the resonant frequency for the 90° polarized wave. Thus, the two resonant frequencies would be identical by asymmetrically adjusting the arm width of the SSRR. Two modified split ring resonators(MSRRs) that are insensitive to the polarization with asymmetric arm width are designed, fabricated and characterized. Excellent agreement between the simulations and experiments for the MSRRs demonstrated the polarization insensitivity in SSRR with asymmetric arm width.2. With the two gaps of the resonator away from the center, the distance between the second resonant frequency for the 0° polarized wave and the resonant frequency for the 90° polarized wave is generally shorter and finally identical. A polarization insensitivity double-split ring resonator(MDSRR) which has two polarization-dependent performances has been designed, fabricated and characterized. The first resonance of the MDSRR sample is polarization insensitive performance for any polarization angle and the amplitude of the second resonant dips could be modulated by rotating the sample in xy plane.3. A triple-split ring resonator has been designed and investigated. By researching the influence of the split opsiton on the resonances for the 0° and 90° polarized waves, a polarization insensitivity triple-split ring resonator have been designed, fabricated and characterized. Excellent agreement between the simulations and experiments demonstrated the polarization insensitivity in the triple-split ring resonator.4. A narrow band-pass filter in superconducting metal has been designed with rectangle unit constraction. And a complementary split ring resonator with dual narrow band in terahertz have been designed, fabricated and characterized in this paper. The filter has two narrow pass bands with the resonant frequencies of 335 GHz and 807 GHz. The transmissions at the two resonant frequencies are 82.7% and 91.8% respectively. The-3dB bandwidth are 35 GHz and 49 GHz. The experimental results agree well with all the simulations.