环形交叉近垂直天线研究

Research of Vertical-cross Loop NVIS Antenna

该文利用两个方环形短波天线垂直交叉组阵,顶端差相位90°馈电,很好的实现了短波信号的近垂直入射天波特性,辐射能量向天线顶端集中,并且在顶端辐射区域内的水平面方向图近似圆形,从而使短波信号经过近垂直入射电离层并反射回地面后能均匀覆盖到天线四周各个方向,不存在盲区并有良好全向性。该结构还改变了以往短波天线单一线极化的形式,实现了天线的圆极化,提高了短波天线对信号极化形式和极化方向的适用性。

A vertical-cross antenna consisted of two square ring shortwave antenna was proposed. The antenna was fed on the top with differential phase in 90deg. This antenna has a good near vertical incidence sky-wave （NVIS） characteristic in the shortwave band. The radiation energy was concentrated to the top of the antenna and the radiation pattern in horizontal plane on the top of the antenna is nearly circular. This structure was also changed the characteristic of traditional short wave antennas in single linear polarization and realized the circu- lar polarization antenna. This structure can also improve the applicability of the shortwave antenna to the form and direction of polarization.