Yttrium Barium Copper Oxide Thin Film for Microwave Communications

这个小企业创新研究第一阶段项目概述了一个计划，以确定薄膜高温超导体（HTS）微波器件性能随功率增加而下降的物理根源。薄膜高温超导最有前途的应用是高频信号处理。由YBa2Cu3O7-x （YBCO）薄膜制成的无源微波器件，如谐振器、滤波器和延迟线，在77K下工作，表现出比传统材料显著提高的性能。然而，通过这些设备传输的信号功率水平只有10毫瓦。大多数商业应用，特别是蜂窝通信，需要功率水平超过10瓦的信号处理。即使是最高质量的薄膜超导体的性能在只有5瓦的输入功率时也会急剧下降！高质量的外延YBCO薄膜将通过激光烧蚀生长，有意改变微观结构特征，如改善外延，化学掺杂和增强晶界；然后将得到的薄膜通过图案化成微带谐振器来表征，以评估其在77K下的微波性能。这些结果将使第二阶段的努力集中在最有希望的方法上，以扩大规模和电路制造。

This Small Business Innovation Research Phase I project outlines a program to determine the physical origins of the degradation in performance of thin-film high-temperature superconductor (HTS) rnicrowave devices with increasing power. The most promising application for thin-film HTS is high-frequency signal processing. Passive microwave devices such as resonators, filters, and delay lines fabricated from YBa2Cu3O7-x (YBCO) thin films and operated at 77K have shown dramatically improved performance over conventional materials. However, signal power levels transmitted through these devices are on the order of only 10 milliwatts. Most commercial applications, in particular cellular communications, require signal processing with power levels exceeding 10 watts. The performance of even the very highest quality thin-film superconductors degrades dramatically at only 5 watts of input power! High quality, epitaxial YBCO films will be grown by laser ablation with deliberately altered microstructural characteristics, such as improved epitaxy, chemical dopants and enhanced grain boundaries; then the resulting films will be characterized by patterning into microstrip resonators to evaluate their microwave performance at 77K. These results will allow the Phase II effort to focus on the most promising methods for scale-up and circuit fabrication.