基于DDS的有源相控阵天线

有源相控阵天线不仅能提高通信系统的性能,而且还能扩充其功能,所以在通信领域的应用越来越广泛.本文介绍一种没有高频移相器的8单元有源相控阵天线系统,它由平面天线阵、数字T/R组件、接收DBF和系统控制分析软件等组成.其基本原理是在发射模式下,利用直接数字合成(DDS)代替传统的高频移相器和衰减器.由于DDS的工作频率比较低,需要通过上变频到系统所需要的工作频率(2.0GHz).在发射模式下,通过控制DDS完成发射波束形成所必需的幅度、相位加权和上变频所必需的本振信号;在接收模式下,则利用DDS技术产生接收信号下变频所必需的本振信号,然后采用DBF技术形成接收波束.文中详细介绍了基于DDS的有源相控阵天线的实现方法和实验结果.通过8单元基于DDS的有源相控阵天线系统的研究,证实了DDS技术在相控阵天线中应用的显著优点和相控阵天线在通信领域具有潜在应用市场.

Active Phased-Array Antenna Based on DDS

The active phased array antenna not only can improve the communication system performance,but also can extend its function,so it is used in communication system more and more widely.This paper introduces an active phased array antenna system that has eight antenna elements without high frequency phase shifters.The system consists of planar array,digital T/R modules,receiving DBF and system control/analysis software etc.The basic theory is:in transmitting mode,the traditonal high frequency phase shifters and attenuator can be replaced by direct digital synthesis(DDS).Because the operation frequency of DDS is very low,the frequency must be converted to needed operation frequency(2 0GHz) by upper frequency conversion.In transmitting mode,through controlling DDS,it produces the amplitude and phase weights needed by transmitting beam,and the local oscillation signal needed by upper frequecy conversion.In receiving mode,through controlling DDS,it produces the local oscillation signal needed by down frequency conversion of the receiving signal.Then the DBF is used to form the receiving beam.This paper introduces in detail the ways and results of the experiment of the active phased array antenna based on DDS.Through the research of eight element active phased array antenna based on DDS, the notable virtues of DDS technology in phased array antenna,and the potential application market of the phased array antenna in communication are proved.