A Topological Directional Coupler Fed by Microstrip Line with Configurable Coupling Coefficient

TL;DR

This paper proposes and demonstrates a topological directional coupler integrated with microstrip lines, featuring a configurable coupling coefficient, applicable in microwave and terahertz frequencies, with both simulation and experimental validation.

Contribution

It introduces a novel topological directional coupler using valley-Hall photonic topological insulators with configurable coupling, integrated with microstrip circuits.

Findings

Achieved various coupling coefficients through configuration.

Validated design through simulation and experiments.

Applicable in microwave and terahertz bands.

Abstract

Topological waveguides have been extensively studied for their robust transmission properties immune to defects and their application potentials for microwave and terahertz integrated circuits. In this work, by using grounded planar valley-Hall photonic topological insulators, a high-efficiency topological directional coupler fed directly by microstrip line with configurable coupling coefficient is theoretically proposed and experimentally demonstrated. The topological directional coupler consists of two coupled topological waveguides, which can be directly integrated with microstrip circuits. Different coupling coefficients were achieved by configuring the coupling between the two topological waveguides. Both simulation and measurement demonstrated the proposed designs. In addition, the proposed design is applicable in both microwave and terahertz bands.