新型低剖面阿基米德螺旋天线设计

设计了一款低输入阻抗的阿基米德螺旋天线。在传统阿基米德螺旋天线的始端加入宽度一定的指数螺蜷线,天线的输入阻抗得到降低,从而放松了对指数渐变微带线馈电巴仑的长度要求。该天线的输入阻抗为75Ω,这使得指数渐变微带巴仑的长度仅为22.5mm即可充分满足天线在2～10GHz频率范围内的馈电要求。天线采用深度为22.5mm(约为最大工作波长的15%)的反射背腔,测试结果表明:在2～10GHz的频率范围内,天线驻波比小于2.5,天线主辐射方向上的轴比小于4dB,方向图对称性良好。

Design of a Archimedean Spiral Antenna with Low Profile

An Archimedean spiral antenna with low input impedance is proposed in this paper.The input impedance could be decreased by modeling an Archimedean spiral antenna with exponentially spiral lines of a constant width.The balun used for feeding can work well with a small length in a large bandwidth.The antenna proposed has a input impedance of 75Ω,and performs well in the frequency range of 2~10GHz.The feed is a exponentially tapered microstrip balun whose length is 22.5mm(only 15% of the largest operating wavelength).The antenna is backed by a 22.5mm deep traditional cavity.In the frequency from 2GHz to 10GHz,VSWR smaller than 2.5,axial ratio at the main direction less than 4dB are measured.