n this paper, we report on the results of features in the discovered effect of a strong change in the microwave losses (quenching) in HTS-based coplanar waveguide (CPW) at certain values of the input power Pin and direct current (dc) Idc. Two waveguides were studied: CPW-150 and CPW-75, fabricated of epitaxial 150and 75-nm YBCO films. The insertion loss of CPW IL = 10 lg (Pout/Pin) was measured versus both the operating temperature and the bias dc current Idc when a fixed level of the input X-band pulsed MW signal Pin was applied. Here Pout is the power measured at the CPW output. A pulse duration Ti was 5 μs with pulse repetition period T = 40 μs. Experiments showed a noticeable difference in specific values of I* = Idc corresponding to the Pin-dependent quenching phenomenon in CPW-150 and CPW-75. With a weak input signal, the difference in behavior of CPWs is anticipated, i.e., quenching occurs at a lower current for thinner film. For Pin > 1 W the situation is opposite, i.e., quenching for CPW-150 takes place at a lower I*. This is explained by stronger microwave heating of CPW-150.
展开▼
