Coplanar Antenna Decoupling Using Soft Surface with Staggered Rectangular Holes

In this work, an improved soft surface with staggered rectangular holes is proposed to reduce coupling between two coplanar ultra-wideband horn antennas. This article finds that although traditional soft surfaces can suppress the propagation of surface waves, when using them to decouple coplanar horn antennas, the S parameter will have a ‘peak’ in the operating frequency band, resulting in poor decoupling effect in that frequency band. Compared with traditional soft surfaces, the improved soft surface proposed in this article can reduce the coupling of coplanar horn antennas by an average of 15 dB in the frequency band of 6 GHz to 18 GHz. It is worth noting that the "peaks" in the frequency band of 9.5 GHz ∼ 11.7 GHz have disappeared, and the coupling of coplanar horn antennas in this frequency band has been effectively improved.