Geometrical Parameters Optimization and Microwave Characterization of Graphene-Based Transmission Lines

Abstract

This study addresses the need to reduce circuit size in integrated circuits, the growing use of monolithic microwave integrated circuits (MMICs) in wireless applications, and the demand for high performance. It investigates the relationship between graphene microstructures and high-frequency behavior by modeling their microwave response through electromagnetic simulations and validating results with on-wafer measurements. The impact of skin depth on microwave performance is specifically examined. Graphene coplanar transmission lines (CPWTLs) were fabricated on silicon wafers and characterized in the 2–20 GHz range. Initial analysis using a CST electromagnetic simulator optimized geometric parameters and predicted RF performance. The optimal structure was fabricated with standard semiconductor techniques and evaluated with a Cascade Microtech probe station connected to a vector network analyzer (VNA). Measurements up to 20 GHz show that graphene maintains consistent properties across the bandwidth with negligible skin effect, outperforming other studies.