broadband microwave balun问题
时间：10-02
整理：3721RD
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各位高手，我最近在看宽带/超宽带方面的文章，看到有人指出broadband microwave balun，有没有哪位有所了解啊，或者有好的文献介绍一下啊，不甚感激
balun就是英文balance to unbalance的缩写，中文叫巴伦，通常用来做单端输入转推挽输出，也兼有阻抗变换的作用，效果类似变压器。宽带巴伦的实现形式那就很多了，例如L band或更低频率可以用传输线变压器来做。更高的微波频段，微带结构的也有，建议google。我以前做过VHF~UHF频段的，不过也忘了细节了
LC balun, Marchand balun, and transformer balun fractional bandwidth 可能不大
multi-stage cascade 可加大頻寬但 size 變大
任意 novel structure 可討論啊！
the ferrite transformer balun is restricted by its upper frequency limit. If the operating frequency becomes higher than about 1 GHz , it simply goes out of order.
The bandwidth of the LC balun is relatively narrow, compared with other baluns, because the body of the LC balun itself, two inductors and two capacitors, is dependent on frequency. This is the unique drawback of the LC balun.
做天线振子的时候要用到。