High Temperature Superconducting Detectors Integrated with Antenna Structures for Millimeter Wave Mixing.

雅人 成瀬

Alexander N. Vystavkin, V. P. Koshelets, G. A. Ovsiannikov

Lincoln C. Bourne, Albert Humirang Cardona, Tim W. James +6 more

Deliberate grain boundaries have been fabricated in epitaxial films of Tl2CaBa2Cu2O8 by growing the films on substrates with localized surface damage and on substrates with surface steps produced with an anisotropic etching process. Bowtie antennas were fabricated to couple millimeter wave radiation into the weak link junctions, which were used as the nonlinear elements. Heterodyne mixing of signals at 55 GHz and 94 GHz was observed in the integrated antenna/detector structures at temperatures below 101 K in the Tl-based films. In addition, observations were made at 55 GHz, using these structures as subharmonic mixers. We have designed an integrated microwave package to measure the noise and conversion efficiency of the grain-boundary junctions at frequencies between 9 GHz and 20 GHz.

Zahra Ehsani, Mahboobeh Baghi Hedeshi, Seyed Mohammad Hassan Javadzadeh

Superconducting detectors play a crucial role in astronomy, particularly at millimeter and sub-millimeter wavelengths, due to their high sensitivity, ease of fabrication, and potential for integration into large arrays.Josephson junction detectors, which utilize high-temperature superconductors, offer a promising design option because they can operate at higher temperatures.In this paper, we aim to design and simulate two detectors based on high-temperature Josephson junctions for millimeter and sub-millimeter waves.To achieve this goal, we employed the Riblet directional coupler to develop detector arrays.We evaluated the frequency response, quality factor, and loss in these detectors.The experimental results indicate that constructing larger arrays and reducing the gap between the coupler and resonators can enhance the quality factor.We demonstrate this improvement by presenting the quality factors for two different gaps in each spectrum.

E. Burstein, D. N. Langenberg, Barry N. Taylor

Kenji Suzuki, M. Ban, Seiichi Tokunaga +3 more

Here we report on the millimeter-wave performance of high-Tc superconducting (HTS) Josephson junctions on MgO substrates, fabricated using a focused Ga ion beam (FIB) technique. The 6 junctions spaced 1.5 /spl mu/m apart from each other occupied 7.5 /spl mu/m. The 6 junctions can modulate even the 1000 GHz electromagnetic wave with nearly equal phase. We applied the YBCO series junction to a millimeter wave mixer with a log-periodic antenna. The HTS junction mixer and the log-periodic antenna are expected to have a function of flat frequency response up to THF. First, we measure wide frequency band responsibility for mixing function below 100 GHz. Next, we observe the HTS mixer-antenna performance as fundamental and harmonic mixers in the wide frequency range up to 100 GHz. Finally, the IF output phases can be changed within 1 dB of IF output power differences.