A high-Tc L-band SQUID amplifier combined with superconductive thin-film filters
نویسندگان
چکیده
An experimental investigation of high-temperature dc SQUID amplifier connected in series with a high-Tc superconductor (HTS) thin-film band-pass filter is presented. The SQUID amplifiers are designed with microstrip input coils and fabricated on bicrystal substrates of zirconia and sapphire with different misorientation angles of 24 and 37 . SQUID parameters are optimized to attain 50-X input impedance for the 1500 MHz central frequency range. The maximum power gain of the amplifier with six turn input coil was measured to be 6 dB at 800 MHz and 4.5 dB at 1750 MHz. Thin-film HTS YBCO filters are based on a band-pass quasi-elliptic prototype consisting of a set of parallel tank circuits connected to a shunt and separated by admittance inverters. The central frequency of the band-pass filter was adjusted close to 1750 MHz amplifier frequency with 4% bandwidth. The natural combination of a high-Tc SQUID amplifier with a HTS band-pass filter allows the reduction of out-of-band noise and optimization of amplifier performance, and demonstrates compatibility with practical components of front-end receiver subsystems. 2001 Elsevier Science B.V. All rights reserved.
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