A Miniaturized Frequency-reconfigurable Rat-race Coupler Based on Metasurface

A novel miniaturized frequency-reconfigurable rat-race coupler based on metasurface (MS) is presented. The frequency-reconfigurable metasurfaced coupler (FRMC), which composed of a microstrip rat-race coupler and an MS, has a compact structure with a diameter of 50mm (0.38λ) and a thickness of 3.048mm (0.02λ). The simulation results indicate that the frequency reconfiguration can be achieved by rotating the MS around the central axis of the source coupler mechanically. The measured results show that the FRMC satisfying a frequency tuning range of 15.2% (2.1GHz-2.4SGHz) can be realized.