Design and characterization of microstrip patch antennas for high-Tc superconducting terahertz emitters

Manabu Tsujimoto; Youta Kaneko; Genki Kuwano; Kanae Nagayama; Takayuki Imai; Yukino Ono; Shinji Kusunose; Takanari Kashiwagi; Hidetoshi Minami; Kazuo Kadowaki; Yilmaz Simsek; Ulrich Welp; Wai-Kwong Kwok

doi:10.1364/OE.420417

Design and characterization of microstrip patch antennas for high-T_c superconducting terahertz emitters

Opt Express. 2021 May 24;29(11):16980-16989. doi: 10.1364/OE.420417.

Authors

Manabu Tsujimoto, Youta Kaneko, Genki Kuwano, Kanae Nagayama, Takayuki Imai, Yukino Ono, Shinji Kusunose, Takanari Kashiwagi, Hidetoshi Minami, Kazuo Kadowaki, Yilmaz Simsek, Ulrich Welp, Wai-Kwong Kwok

PMID: 34154249
DOI: 10.1364/OE.420417

Abstract

We designed and characterized a microstrip pattern of planar patch antennas compatible with a cuprate high-T_c superconducting terahertz emitter. Antenna parameters were optimized using an electromagnetic simulator. We observed repeatable sub-terahertz emissions from each mesa fabricated on identical Bi₂Sr₂CaCu₂O_8+δ base crystals in a continuous frequency range of 0.35-0.85 THz. Although there was no significant output power enhancement, a plateau behavior at a fixed frequency was observed below 40 K, indicating moderate impedance matching attributable to the ambient microstrip pattern. A remarkably anisotropic polarization at an axial ratio of up to 16.9 indicates a mode-locking effect. Our results enable constructing compactly assembled, monolithic, and broadly tunable superconducting terahertz sources.