多阶阻抗匹配与宽频带天线的设计分析

为了实现天线的宽频带，从阻抗匹配的基本理论出发，将天线等效为单端口的微波谐振电路，通过多阶阻抗匹配网络来实现天线阻抗带宽的展宽．在具体的天线设计中，可以在天线的馈电网络上或者辐射体上进行多阶阻抗匹配．给出的两个实例验证了多阶阻抗匹配的可行性和有效性．研究结果表明，通过在弯折单极子天线引入阻抗匹配环，实现了二阶的阻抗匹配，其相对带宽从9.70%增加到46.80%；通过在套筒单极子天线引入4根匹配金属柱，实现三阶的阻抗匹配，其相对阻抗带宽从55.14%展宽到82.11%．

Design and analysis of multi-tuned impedance matching and broadband antennas

In order to broaden the impedance bandwidth of an antenna, the multi-tuned impedance matching technology can be utilized. An antenna can be equivalent to a single-port microwave resonant circuit according to the theory of impedance matching. In a practical antenna design, multi-tuned impedance matching can be performed on either the antenna feed network or the radiator. Two examples are given to validate the feasibility and effectiveness of the multi-tuned impedance matching technology. Experimental results show that a folded monopole achieves double-tuned impedance matching by introducing a loop, thus enhancing its fractional impedance bandwidth from 9.70% to 46.80%. In addition, a sleeve antenna obtains a triple-tuned impedance matching with the presence of four metal pillars, thus improving its band of operation from 55.14% to 82.11%.