Nonlinear coplanar waveguide on the basis of high-Tc superconducting thin film

In the present paper, coplanar waveguides based on HTS thin films with two thicknesses were fabricated and their nonlinear properties were studied. Very weak nonlinear effect was observed at liquid nitrogen temperature. The effect increases under dc-bias applied to CW at T=77K and with increasing temperature up to critical value. The behaviour of phase coefficient for propagation constant is revealed to be strongly dependent on input power. The experimental results are in good agreement with theory, although the thermal effects are noticeable. The results show that planar transmission lines based on HTS thin films are promising structures for development of microwave signal limiters.