异物对天线性能的影响分析

针对异物的存在将对天线性能产生影响这一问题，设计了一款单臂阿基米德平面螺旋天线。该天线的尺寸相对较小，剖面极低，具有良好的宽频带特性和圆极化特性。通过HFSS软件模拟仿真并分析异物如铁块、木头、肌肉组织等对天线性能的影响。仿真结果表明：磁导率较大的铁块与介电常数较大的肌肉组织对天线性能影响较大，介电常数小的木头对天线性能影响较小；异物尺寸越大对天线性能的影响越明显；异物距天线轴向的横向距离不同对天线性能的影响程度也有所不同。分析结果为天线作为一种异物检测工具的可行性提供了理论依据。

Analysis of the effect of foreign objects on antenna performance

Aiming at the problem that the existence of the foreign objects will cause interference to the antenna performance, a single arm Archimedean planar spiral antenna is designed in this paper. The size of this antenna is small and has an extremely low profile, so a good wideband and circular polarization characteristics can be realized by this structure of antenna. The effect of foreign objects, such as iron, wood and muscle tissue, at close range to antenna is simulated by HFSS software. The simulation results show that the iron of large magnetic permeability and the muscle tissue of large dielectric constant have a great influence on the performance of antenna, while the wood of small dielectric constant has a weak influence. The bigger the size of foreign object, the greater the effect act on the performance of the antenna. The influence degree will be different if the horizontal distance from the foreign object to the antenna is different. The anforeign objects, Archimedean spiral antenna, VSWR (voltage standing wave ratio), circular polarizationalysis results can provide a theory basis for the feasibility of antenna to be one kind of method of foreign object detection.