H. Kanaya et al., Coplanar quarter-wavelength resonator filters fabricated by the superconducting sol-gel films, IEEE APPL S, 9(2), 1999, pp. 3913-3916
High temperature superconducting Y-Ba-Cu-O films were prepared on MgO polyc
rystal substrates by the sol-gel process. The average transition temperatur
e and the surface resistance are 83K and 2.8m Omega (at 30 K and 9.9GHz, in
put power = -10dBm), respectively. We fabricated a YBCO coplanar waveguide
(CPW) quarter-wavelength (lambda/4) resonator around 2GHz (the length of th
e resonator is one half as long as that of the popular half-wavelength (lam
bda/2) resonator) and compared its RF properties with that of a lambda/2 re
sonator. Moreover, 2-pole CPW bandpass filter using YBCO sol-gel film was c
onstructed with capacitively coupled lambda/4 resonators. It has a narrow f
ractional bandwidth (3.60%) at 30K.