Abstract-Multi-Band Terahertz Filter with Independence to Polarization and Insensitivity to Incidence Angles

Limei Qi, Chao Li,
http://link.springer.com/article/10.1007/s10762-015-0202-4

Multi-band terahertz filters with independence to polarization and insensitivity to incidence angles are designed, fabricated, and measured, respectively. The promoted multi-band terahertz filters consist of two and three concentric ring complementary structure. Compared with the dual-ring structure, the triple-ring structure not only increases numbers of the pass bands but also heightens the out-of-band rejection of the middle band. The physical mechanisms of the multi-band resonant responses are clarified using three different configurations and distribution of magnetic fields and current surfaces. At normal incidence, the triple-ring structure is independent to polarization due to the symmetry. At oblique incidences, transmission magnitudes as a function of the frequency are firstly demonstrated for the multi-band filter; it is found that this structure shows great insensitivity to incidence angles. The multi-band filter also has advantages in easy fabrication. The encouraging results afforded by the design of the filters could find applications in multi-band sensors, terahertz communication systems, and other emerging terahertz technologies.