Modeling Strategies for Superconducting Microstrip Transmission Line Structures

Area of Science:

• Electromagnetics
• Superconductivity
• Materials Science

Background:

• Electromagnetic simulation of large superconducting transmission lines is computationally intensive.
• Accurate modeling requires considering complex superconducting properties like surface reactance.
• Existing methods may struggle with the scale and specific physics of superconducting structures.

Purpose of the Study:

• To develop strategies for reducing electromagnetic simulation time of electrically large superconducting transmission line structures.
• To maintain high model accuracy during simulation time reduction.
• To investigate the impact of superconductor properties on transmission line characteristics.

Main Methods:

• Utilizing Bardeen-Cooper-Schrieffer (BCS) theory to evaluate the complex surface reactance of superconducting sheets.
• Employing commercially available electromagnetic simulation software for calculations.
• Comparing simulation results with analytical models from existing literature.
• Analyzing the influence of geometric parameters (line width, metallization thickness, substrate height) on microstrip transmission lines.
• Presenting a scaling approach to correct for numerical simulation artifacts.

Main Results:

• The BCS theory-derived surface reactance accurately models phase velocity and characteristic impedance for finite transmission lines.
• Simulation results show good agreement with analytical forms.
• Geometric parameters significantly influence microstrip transmission line propagation.
• The proposed scaling approach effectively compensates for leading-order effects in numerical simulations.

Conclusions:

• The integration of BCS theory and a novel scaling method offers an efficient approach for simulating superconducting transmission lines.
• Accurate modeling of kinetic inductance is essential for understanding transmission line dispersion, especially near the superconductor's energy gap.
• This work provides a pathway to faster and more accurate electromagnetic simulations for advanced superconducting electronics and power transmission.