High-temperature superconducting wide band delay lines

Stripline non-dispersive delay lines with 20 GHz of bandwidth were designed and fabricated using YBCO thin films deposited on both sides of 2-inch-diameter, 10-mil thick LaAlO/sub 3/ wafers. A double-wound spiral configuration was used yielding a line length of approximately 150 cm. Novel approaches were used to minimize the effect of air gaps between the two substrates needed to form the stripline structure, and to realize a wide band transition from the coaxial external connections to stripline. Experimental results showed 5 dB of insertion loss at 20 GHz, with 1 dB amplitude ripple over most of the 0-20 GHz, range for a 22.5 ns delay.<
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