Design and Fabrication of Superconducting Double Spiral Filter

Manabu KAI  Teru NAKANISHI  Akihiko AKASEGAWA  Kazunori YAMANAKA  

IEICE TRANSACTIONS on Electronics   Vol.E86-C   No.12   pp.2417-2421
Publication Date: 2003/12/01
Online ISSN: 
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Issue on Recent Trends on Microwave and Millimeter Wave Application Technology)
Category: Passive(Filter)
spiral,  superconductor,  filter,  Q factor,  

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This paper reports the design and fabrication of a miniaturized superconducting microstrip line filter using YBCO film on MgO. The filter's resonators are shaped in a double spiral, and the size of the resonators is optimized from the standpoint of the unloaded Q-factor. The 15-pole bandpass filter that has the center frequency of 1.95 GHz and the bandwidth of 20 MHz is designed in the size of 9.7 44 mm. The simulated S-parameter characteristics of the filter is corresponding to the initial design parameters. We fabricated the filter on an MgO substrate with a diameter of 2 inches. The filter had very sharp cutoff and a very low insertion loss of 0.14 dB.