基于槽线与微带过渡结构的高隔离巴伦设计

Design of a Balun with High Isolation Based on the Slotline and Microstrip Transition Structure

提出了一种基于槽线与微带过渡结构的新型高隔离巴伦。首先,本设计采用槽线与微带的过渡结构,它与魔T的腔体结构类似,能够在工作频段内输出严格平衡的两路信号。同时采用槽线与微带的过渡结构可以使本设计更加紧凑方便地集成于一层基板上,这种紧凑的平面结构可以很好地克服腔体魔T体积大,不易集成的缺点。然后,在距离槽线到微带过渡结构半波长处的输出端口加由电阻和微带线构成的隔离网络,这样就可以产生很好的隔离度。实测结果显示,该巴伦在7~10GHz的插损为1.9dB,隔离度在6.1~11GHz大于17dB,并在6.2~7.3GHz和8~11GHz频段内隔离度大于20dB,两输出端相位差为180°。

A new type of Balun with high isolation based on the slotline and microstrip transition structure was presented.Firstly,this design used the transition structure of slotline and microstrip,which was similar to the structure of magic T and could produce two strictly balanced signals in working frequency range.At the same time,the slot line and microstrip transition structure could make the design more compact and convenient when integrated in a layer of substrate.This compact planar structure could overcome the disadvantages that this circuit was too large and hard to be integrated.Then,an isolated network consisting of two resistances and the microstrip was added to the output port which was half wavelength distance from the slotline-tomicrostrip transition,resulting in good isolation.The measured results show that the loss from 7GHz to 10 GHz is lower than 1.9dB,the isolation from 6.1GHz to 11 GHz is greater than 17 dB,the isolation is greater than 20 dB from 6.2GHz to 7.3GHz and from 8GHz to 11 GHz,and the skewing of two output ports is 180°.