how to optimize with ADS?

[rda]

i design this branchline coupler as you see in this pdf but i'd like to optimize it!!

so can someone help me?

the characteristics of my coupler:

the upper freq=2.17ghz
the low freq=1.92ghz
freq design f0=2.045ghz

C(coupling coeff)=3db

 

[tyassin]

Hi

There is a Design guide in ADS that can make the complete design of among others branch-line couplers.

Regards

 

[khouly]

u need to read the optimization manul in ads , it is simple to use

khouly

 

[rda]

ok i tried what you suggested to me and here i upload the results , so what do you think guys about this results in compare with the first ones!

S(1,1) at the upper freq=-13.54 db
S(4,1) at the upper freq=-13.00 db
are this results good?
because i read somewhere that we must always have S(1,1) and the isolated port S(4,1) <14.6 db

 

[supersage]

Usually, we would like to have S11 and S41 less than -20dB.

 

[erno]

I made a quick simulation and will attach the results. Branchline hybrid with one section is a liitle bit too narrow for this wide 250 MHz band. You should add one branchline section more.

Basically this kind of optimization is very trivial to be made in ADS and you will find the optimization goals I was using in the schematic. I hope you will get some advise you asked.

I added the FR-4 board dielectric loss to the MSub properties, please use the data according to manufactur data. Isolation is better than 19 dB over the 250 MHz band with matching better than 18dB at all ports. By adding some more elements to the circuit broader bandwidth can be met but that is another story.


Regards

Erno