面向车载鲨鱼鳍的宽频MIMO天线设计

为了解决车载通信天线工作频带窄、尺寸大等缺点,文中提出了一款应用于车载鲨鱼鳍外壳的新型小型化、宽带MIMO天线。为了实现天线的宽带特性,充分利用了印制单极子天线易于引入多谐振的特点,首先通过合理的尺寸设计,将单极子天线谐振频率设计至工作频段中;然后,使用缝隙加载技术,增加天线谐振模式数量并改善天线阻抗匹配特性,拓宽了天线带宽并实现了天线的小型化。为了验证天线实际性能,将天线安装于鲨鱼鳍外壳中进行了测试。结果表明,该天线可以覆盖824～5 000 MHz的频段范围,驻波比均小于3,增益最低1.9 d Bi、最高6.2 d B,效率均高于49.5%、最高达89.2%。该天线可满足车载通信系统对天线的宽带化和小型化要求。

Design of a Wideband MIMO Shark-fin Antenna for Vehicular Applications

The vehicular antenna generally suffers from the narrow operating band and large profile. To solve this problem, a low-profile wideband antenna is designed to install in the shark-fin housing of the vehicle. To realize the proposed wideband antenna, the resonant modes of a PCB monopole is fully exploited. By properly designing the antenna size, the resonant frequencies of this monopole are drifted to the operating band. Then the slots are deliberately designed and loaded on the monopole. Thus, more resonant modes are generated, and the antenna matching performance is improved to increase the bandwidth. Eventually, a compact antenna size is obtained. For demonstration, the proposed antenna is installed into the shark-fin housing for measurement. As exhibited by the measurement results, the operating band (824-5 000 MHz) can be covered by the proposed antenna. The antenna VSWR is less than 3, the minimum gain is 1. 9 dBi and the maximum gain is 6. 2 dBi, and the efficiency is from 49. 5% to 89. 2%. This indicates that, the proposed antenna can satisfy the wideband and compactness requirement of the vehicle communication.