一种VHF频段高性能定向耦合器的设计与实现

Design and Realization of a High-performance Directional Coupler at VHF Bands

设计了一种用于功率检测和获取的无源器件——定向耦合器.首先利用传输线耦合器与集总参数耦合器的等效性,分析得出了集总参数耦合器各个元件参数与性能指标的理论公式.再针对甚高频(VHF)频段,传输线耦合器一般无法做到结构紧凑,而集总参数元器件传输功率的限制等问题,同时考虑到弱耦合以及高定向性的设计要求,提出了微带线电感与集总参数相互结合的解决方案,并设计出定向耦合器的模型.然后,结合在研RF系统100 MHz中心频率3、00 W传输功率的实际需求为例,验证了耦合器模型的正确性,并利用ADS软件对其做出了原理图和矩量法仿真.最后给出了制版后实际测量的性能曲线,并对测试结果做出了分析.

This paper designs a kind of passive device – directional coupler used for power detection and extraction.At first,analyses and abtains the theory formulas contacting each component and performence target,by using the equivalent of transmission line（TL） couplers and lumped element（LE） couplers.Then for the high frequency（VHF） bands,TL couplers are hard to carry out to be tight structures,and lumped elements have the limits of transmission power,considering the design targets of loose coupling and high directionality as well,this paper proposes a solution method consisting of lumped elements and microstrip inductors,and designs a coupler model.Furthermore,according to the real requests as 100 MHz centre frequency and 300 W transmission power of the developed RF system,the validation of model correctness is given,and the schematic and momentum simulation are implemented by ADS software in this paper.The measured performance curves of real circuit and measured results analysis are presented at last.