Shielded and open two-layer superconducting microstrip lines

The full wave analysis in the spectral domain of the Transverse Transmission Line (TTL) is used in the analysis of the shielded and open two layers microstrip lines considering the superconductor strip and semiconductor substrate. The superconductor effect is included with the boundary condition of the surface impedance that is calculated from an advanced two-fluid model. Considering that the thickness of the strip is more thin than the penetration depth, the surface current and the fields within the strip are approximately uniforms. For a substrate with high permitivity, the density of current will be practically equal to current in the bottom of the strip. Applying the Moment method is obtained the homogeneous matrix system, and the complex root of the characteristic matrix is the complex propagation constant of the structure, including the phase constant and the attenuation constant. Results are presented for the complex propagation constant, of the shielded and open two layers superconducting microstrip lines versus the frequency and the temperature, where the effects of the material superconductor are shown.