We investigate resonance behaviors of optically thin metallic slot antennas on finite substrates in terahertz frequency regime. By carefully analyzing theoretical and experimental results, we observe that slot antennas fabricated in a gold film with a thickness below the skin depth of gold show blueshifted resonance frequencies for the increasing slot width, while the opposite resonance behaviors appear when the slot antennas are perforated in perfectly electric conductor. In addition, we find that for slot antenna sustained by a finite substrate its thickness and the slot width are additional crucial factors determining the resonance frequency of slot antennas.
Bibliographical noteFunding Information:
This work was supported by the Korea Science and Engineering Foundation (KOSEF) (SRC, Grant No. R11-2008-095-01000-0) and the Korea Research Foundation (KRF) grant funded by the Korea government (MEST) (Grant No. 2009-0071309), KICOS (GRL, Grant No. K20815000003), Seoul Science Fellowship, and the Seoul R&BD Program (Program No. 10543).