any advices about how to design the balun?

go to this link.
It is cutom link 4 u. It is software in chinese.

https://www.edaboard.com/viewtopic.p...ght=rf+toolbox

depends on the frequency range..., on PCB? with transmission line (possible with coaxial cable)?
therefore you should share more details...

Thank you very much.
Where are you now?I am working as PE for DECT phone at ZhuHai.Now,i am on a trip at Fukuoka.Japan.

I am a new guy about this system,i am glad if i can make friends with you.

Added after 19 minutes:


thanks for you advices

frequency range 1880MHz---1900MHz
transmission condition on PCB

I need two balun,one is for transmission signal,the other for receive signal.

Transmission balun have to transfer the differential signal from output inside bbic port to input port inside amp ic.What's more,could i do something to control the 2nd harmonic on this balun?

Recieve balun only transfer the single-signal to differntial signal.

Could you give me some ideas about how to caculate balun's width and length,and the distance between the two copper?


best wishes

You may find in the books different kinds of baluns printed on the board, but last years it is easier to buy small size chip ceramic baluns. They are not expensive and widely available. Usually they are outperform printed baluns and occupied less board real estate. Often the cost of board space is more than the price of this chip balun. You may check Murata, Toko, TDK, Soshin, may be Minicircuits.

thank you very much.

but what i want to know is how to design these balun,could you give me some ideas?

There are different balun technologies available. Which one is better depends on your particular requirements. You may check Brian Wadell's Transmission lines handbook, or there is one book about coupling circuits (I do not remember exact title, but may check it if necessary). You will find some information about balun technologies.

Sorry, I made mistake. Wadell's book has no balun. I confused it with this book: Mongia; Bahl; Bhartia. RF and Microwave Coupled-line Circuits. There is Chapter 11 about balun.

thank you very much,i will go to find it in book store.
maybe it is a bit expensive!