single input - differential output RF circuit

[wccheng]

differential output antennas

Dear all,

Could anyone suggest the circuit for single input and differential output in RF band? Since I see some circuit building block, which use single ended antenna and then feed into the RF chip. In the RF chip, it has one building block for single input - differential output. Then connected to differential LNA.

However, I don't know what kind of the circuit could make a single input - differential output for RF high frequency. Could anyone tell me?

Thanks

wccheng

 

[frannk]

single to differential output

What's your frequency and bandwidth? You can design a balun to go from single ended to differential.

 

[wccheng]

3GHz to 5GHz.

Do you have any suggest paper to me?

Thanks

 

[Manjunatha_hv]

Hello wccheng,


Yes, Balun will address your requirement...
Attached are the Two good articles on the requested topic...
By the way what is the implimentaion application, is it a PCB or LTCC or MMIC?




---manju---

 

[noiseless]

Same question about balun.
Q1: for the frequency above 1G, in the simulation, people usually use transformer or balun to transfer single input to differential?

Q2: matching network should be between input and balun or between balun and LNA?

Q3:I found in the test, s11 is big different to the simulation. I tried to put balun measurement data(given by factory) .s3p to the port3 block as real balun to do the simulation, however, I found the result is somewhat very weird. I'd llike to know what experts do in their simulation with balun!

thanks.

 

[melc]

https://www.tdk.co.jp/tefe02/e8balun_hhm.pdf

I have doubts you may adapt a stripline or a microstrip balun perfectly in 3-5Ghz range. Maybe using smallest frequency range?

 

[asb1211]

Balun alway requires much chip area. Anyone can suggest a circuit for frequency from DC to 3 GHz?

 

[flamingo]

Maybe common-source and common-gate with same amplfication factor can be used, one is positive gain, the other is negative gain. The problem is to ensure that two circuits provide same abosulte gain. Just an idea

 

[asb1211]

Common-source and common-gate have very much different input impedance which makes it quite hard to have same absolute gain. it's an idea, though, hard to implement.

 

[ning0703]

for single port to differential port we know we need to use balun ,but for the differential line matching circuit , can some one give some suggestion , how to tune the matching circuit ?