基于新型超宽带平面巴伦的双平衡混频器

A Novel Doubly Balanced Mixer Using Planar UWB Balu

首次基于新型超宽带平面巴伦,设计了工作于超宽带(3.1~10.6GHz)频段的二极管双平衡混频器。微带到槽线过渡巴伦具有高通性质,可以阻断直流和中频分量,而微带到共面带线(CPS)过渡巴伦可以提供中频和直流回路,二者与交叉二极管对一起构成平面超宽带双平衡混频器。同时,可在中频端口串接宽阻带低通滤波器,进一步改善射频(RF)和本振(LO)端口到中频(IF)端口的隔离度。根据测试结果,当射频和本振信号工作于3.1~10.6GHz,中频在DC^100MHz时,变频损耗小于13dB,三个端口之间的隔离度大于25dB。

For the first time, this paper proposed a planar UWB doubly balanced diode mixer operating over 3.1-10.6 GHz using novel planar balun. Microstrip-to-slotline transition balun can block IF and DC components due to the high-pass nature, and microstrip-to-CPS balun can provide DC and IF return, both together with the crossover diodes construct the doubly balanced mixer. The isolation can be better improved through a low pass filter connected to the IF port. From the measured results, the mixer exhibits a conversion loss of less than 10 dB covering DC-100 MHz IF and port-to-port isolations of better than 25 dB over the RF and LO bandwidths of 3.1-10.6 GHz.