基于圆波导缝隙的双极化水平全向阵列天线设计

Design of Dual-polarized Horizontal Omnidirectional Array Antenna Based on Circular Waveguide Slot

设计了一种具有水平全向辐射特性的双线极化圆波导缝隙阵列天线。利用双模式转换器馈电,以提供天线所需的TM01及TE01模式,并抑制波导内其余高次模和基模的传输;通过沿圆波导周向交错排列的矩形横缝及纵缝,分别实现垂直和水平极化;其中将横向矩形缝隙设计为平行双环结构来增加带内谐振点,进而拓展天线的工作带宽;此外,将两种缝隙沿波导轴向进行组阵,并在天线阵列末端设计了匹配结构用以减小TM01模式所带来的能量反射。仿真结果表明:该天线两种极化方式电压驻波比小于2的驻波带宽为2.75 GHz~2.95 GHz,并且整个工作频段内,两种极化方式下的增益均超过7.5 dB,水平面内不圆度小于1.8 dB,可适用于气象雷达领域。

A dual-polarized circular waveguide slot array antenna with the characteristic of horizontal omnidirectional radiation is designed.The antenna is fed via dual-mode converter to motivate the TMor and TEor modes and suppress the transmission of other high-order modes or fundamental mode in the waveguide.The vertical and horizontal polarization of the antenna are realized by the alternate permutation of rectangular transverse and longitudinal slots along the circumference of the circular waveguide;the transverse rectangular slot is designed as a parallel dual-ring structure to increase the resonance point in the band,thus expanding the working bandwidth of the antenna.Furthermore,the two types of slots are grouped along the waveguide axis,and a matching structure is designed at the end of the antenna array to reduce the energy reflection brought by TMor mode.The results of electromagnetic simulation reveal that the voltage standing wave ratio is lower than 2 from 2.75 GHz to 2.95 GHz,and within the whole working frequency band the gain is more than 7.5 dB,and the non-circularity in the horizontal plane is less than 1.8 dB.The as-designed antenna is promising in the field of meteorological radar.