A superconducting signal transmission apparatus provided with a vacuum container
11, a superconducting electronic device 12 provided in the vacuum
container 11, an input side transmission line 13 and output side
transmission line 14 for connection to the superconducting electronic device
12 through the vacuum container 11, and a cooling mechanism (15,
16, 17) for cooling the superconducting electronic device 12 and further
having a heat cutoff signal transmission unit 20 inserted at least at part
of the input side and output side transmission lines 13 and 14. The
heat cutoff signal transmission unit 20 is comprised of a substrate 31
and a flat circuit body 30 provided with a signal transmission line
32 and ground layer (33, 33-1, 33-2). The substrate
31 is comprised of a dielectric material having a small heat conductivity.
The conductor portions forming the signal transmission line 32 and the ground
layer are formed with thin thicknesses enabling suppression of the inflow of heat
from the outside.
