基于平面宽带耦合抑制结构提高天线端口互隔离度的方法

A Method to Improve the Mutual Isolation of Antenna Ports Using Planar/Wideband Coupling Suppression Structure

由于通信任务的多样化需求,同一系统中会集成多个不同频段的天线.相邻天线不可避免地会相互影响,导致天线端口的互隔离度下降.为提高双频段天线端口之间的互隔离度,本文提出了一种加载于低频单元上的平面、宽带耦合抑制结构(Planar/Wideband Coupling Suppression Structure,PWCSS),该耦合抑制结构谐振在高频段,可以有效减小低频单元在高频段的雷达散射截面(Radar Cross Section,RCS),使低频单元辐射的高频能量被吸收,进而提升两天线单元在高频段的端口互隔离度.本文提出的PWCSS有以下优点:不会给低频单元带来额外的增益损失、不会对天线原有辐射方向图产生影响;不需要分层加工,成本低,集成度高;包含不同长度、不同位置的开路微带,可以有效地扩展耦合抑制的作用带宽.对天线进行了仿真、加工和测试.结果表明,采用PWCSS可使高频范围内平均互隔离度、最大互隔离度分别提高16.6 dB和30 dB.该耦合抑制方法可用于基站、探测、雷达等多天线系统,具有良好的应用前景.

Diversified communication mission requires more and more antennas to be integrated into the same system.Adjacent antennas inevitably influence each other,leading to a decline of the mutual isolation of the antennas’ports.This paper proposes a planar/wideband coupling suppression structure(PWCSS)resonated in the high frequency band to reduce the radar scattering cross section(RCS)of the low band element and absorb energy from the low band element in the high frequency band and improve the mutual isolation of the two antenna elements’ports in the high band.Compared to the previous approach,the PWCSS proposed in this paper has the following advantages.First,its usage will not bring extra gain loss for lower band element,and will not affect the radiation pattern of both the lower and higher band elements.Second,it does not require lamination process,which means low cost and high integration.Third,it contains open circuit microstrips with various lengths and positions,which can effectively extend the bandwidth of coupling suppression.The author simulated,manufactured and tested the antenna.Results show that the average/maximum mutual isolation in the high frequency band can be enhanced by 16.6 dB and 30 dB when the PWCSS is applied.This coupling suppression method can be very useful to base station,detection,radar and other multi-antenna systems,and has a good application prospect.