地板及金属板加载对轴向模螺旋天线辐射特性的影响

轴向模螺旋天线是一种常见的圆极化辐射的定向天线,其辐射方向主要是沿着螺旋线的轴线方向。通过改变天线地板的尺寸可以对天线的辐射方向进行调整,使之向地板一侧进行辐射,并能够获得较好的圆极化与定向辐射特性。通过轴向辐射方向的金属板加载,可以显著地提高天线的增益。以一个传统的轴向模螺旋天线为例,对上述两种控制天线辐射效果的方法进行了仿真与实验研究,结果表明减小地板直径可以使天线辐射向着地板方向,并且能够达到约10 d B的前后比;在天线轴向的加载地板可以使天线增益提高1 d B以上,并且对天线的阻抗带宽及圆极化特性等性能影响较小。上述方法的采用可以使得轴向模螺旋天线的应用更加广泛。

Effect of metal ground and loaded metal wafers on the radiation characteristics of axial-mode helical antenna

Axial-mode helical antenna is a normal circularly polarized radiation and directional antenna, whose radiation direction is mainly parallel with the helical axial direction. The size of the metal ground can be changed to adjust the radiant direction towards the side of ground, in addition, better circularly polarized and directional radiation characteristics can be achieved as well; on the other hand, antenna gain can be improved obviously by introducing metal wafers with axial radiation. These methods of changing size and loaded wafers are simulated and experimented with a traditional axial-mode helical antenna, then the results indicate that the decreasing ground size makes the radiant direction turn to the ground, at the same time, the front to back ratio can be about 10dB; the antenna can boost 1dB in gain under the circumstance of wafer-loaded with less impact on antenna impedance bandwidth and circular polarization characteristics. Therefore, the axial-mode helical antenna can be applied more widely with mentioned methods above .