Design of Wideband Planar SIW Horn Antenna Loaded with Epsilon-Near-Zero Metamaterials

In this letter, a novel SIW horn antenna structure loaded with epsilon-near-zero (ENZ) metamaterials is proposed. The metamaterial unit consists of metallized vias, which simplifies the design of the antenna while maintaining a planar structure. Combined with Drude model and S-parameter extraction method, the working frequency band of metamaterial with ENZ property is firstly determined. The results show that after the designed ENZ metamaterials structure is loaded into the SIW horn antenna, the proposed SIW horn antenna can greatly improve the impedance mismatch problem while ensuring high gain, and the relative impedance bandwidth of the antenna is increased to 24.8%. The measured results further verify the correctness of the theoretical analysis.