To enable impedance matching, even if the normally conducting resistance as a mixer of a Josephson element is small and has variance by forming respective elements of an antenna, a mixer, and a filter by using a superconducting thin film and forming a dielectric film, even on one of strip lines from the elements to an intermediate-frequency signal taking-out part.
On the entire surface of a substrate, a YBaCuO-based superconducting thin film is formed and patterned by photolithography. Consequently, a Josephson element is formed on an artificial grain boundary 15 as a mixer 5. After the patterning, a ferroelectric body BaTiO3 is filmed on the strip line 8a, and then an electrode 102 is vapor-deposited by using Au. A voltage is applied to the ferroelectric film on the strip line 8a to make the polarizing direction uniform, the capacity of the strip line 8a of the superconducting thin film is varied by coupling to vary the impedance. Then the voltage is adjusted to control the impedance and match the entirety.
SHIMODA TATSUYA
KAMIKAWA TAKETOMI
NATORI EIJI
