A 3 dB Coupler With Defected Ground Structure for Feeds Applied to High-Power Intelligent Metasurface

– This paper proposes a 3 dB coupler with high-power handling capability feeds applied to high-power intelligent metasurface, based on loosely coupled structures and defected ground structure (DGS). The proposed coupler structure consists of two tandem coupled couplers with a coupling coefficient of 8.34 dB and a DGS, a design that significantly enhances the couplers’ ability to handle high power levels. The measurement results are in good agreement with the simulation results: within the 3.5 to 4.5 GHz range, the return loss exceeds 21.4 dB, the isolation is at least 20.8 dB, the insertion loss is less than 0.3 dB, and the phase difference between output ports is 93–94.5^◦. Furthermore, the coupler can handle high power exceeding 1.5 kW with a 10% duty cycle. The proposed 3 dB coupler features low insertion loss, high isolation, low return loss, high-power capability, and can improve the power capability of intelligent metasurface systems.