用人工磁导体改善增益的宽带圆极化天线

Broadband Circularly Polarized Antenna Improved Gain Using AMC Reflector

本文设计了一种用人工磁导体(Artificial magnetic conductor,AMC)反射板改善增益的宽带圆极化方形缝隙天线,采用L型贴片耦合馈电方式,其工作频率覆盖了3.7 GHz~4.2 GHz的C波段.通过在方形缝隙的对角线处嵌入两个小的方形贴片来产生两个相互正交的表面电流,实现了右旋圆极化辐射;在L型贴片单元与共面波导馈线之间引入一个短截线,使天线在一个较宽的频段内获得阻抗匹配,展宽了天线的阻抗带宽和轴比带宽.此外,通过在方形缝隙天线正下方加载一个4×4的矩形人工磁导体反射板来改善天线的增益,实现了天线的单向辐射.仿真和测试结果表明,天线的阻抗带宽为3.58 GHz~4.16 GHz,轴比带宽为3.5 GHz~4.05 GHz,相对轴比带宽为14.6%,峰值增益为6.0 dBi.

In this paper,a broadband circularly polarized square slot antenna improved gain with AMC reflector is designed.The proposed antenna is coupled feed by L-shaped patch.The operating frequency band covers the C band of 3.7 GHz~4.2 GHz.Two small square patches are embedded in the diagonal of the square slot,then two orthogonal surface currents are generated and then right-handed circularly polarized radiation is realized.A stub is introduced between the L-shaped patch and the coplanar waveguide feed line to improve the impedance matching of the antenna,then the wide impedance bandwidth and wide axial ratio bandwidth are obtained.In addition,a 4×4 rectangular artificial magnetic conductor reflector is loaded under the proposed antenna to improve the gain,and the unidirectional radiation of the antenna is realized.The simulated and measured results show that the impedance bandwidth of the antenna is 3.58 GHz~4.16 GHz,the axial ratio bandwidth is 3.5 GHz~4.05 GHz,the relative ratio bandwidth is 14.6%,and the peak gain is 6.0 dBi.