Question of design Ku band GaAsMESFET power amplifier

When I do not know the big signal model, power S parameters, and the dynamic resistance of the GaAsMESFET, how to do the match of the GaAsMESFET?
Thank you!

Could anyone help me?

Hi,

if you want to design a matching network without any data it will be almost imposible (you have to know at least something!). If you have small signal S parameters you can try starting from them and put some trimming pads in the layout to trim the performance in the large signal operation. Then you can take those trimmings into account and make a final layout.

If you really don't have anything to start with, the best way is to use tuners with the device and do a load pull measurements, but I assume this is not the option for you. You can get close to this by puting a transistor to a jig having only reasonably long 50Ohm lines at input and output and then play a bit with moving around and soldering down some copper tapes stubs to get close to the desired performance. Then you can simulate your trimmings and get the idea what device likes to see. Then you can design matching networks with trimming pads and repeat the cycle. This is very primitive and slow but it gives results!

flyhigh

At the least device vendors will provide you the measured S-Parameters...
You can start from that point designing the PA

Here are couple of good articles helps you how to design...

http://www.rfcafe.com/references/art..._copyright.pdf

http://scholar.lib.vt.edu/theses/ava...cted/chap3.PDF

---manju---

Thanks you all very much!
I benefit a lot from your suggestions!
Thanks !

hi,manju,
I have read the pdf books you suggested, but I can not find the software MultiMatch in internet, can you introduce me somewhere to download it or could you email it to me?
My email is zhulei19811003@hotmail.com
Thank you!

Hello ChaoFan,


You can register & download the software using following link...

http://www.ampsa.com/mosaicDemoRegFrm.htm

Also it has a Script interface to AWR Microwave Office, which helps to quickly simulate & analyse your ckt...


---manju---

Hello manju,
Thank you very much, Can I know your email?

If you want to discuss or need any help...here you go....

manjunatha_hv@rediffmail.com

Hi,

3 useful papers

flyhigh

hi,flyhigh
Thanks for your help.
I have read "RF-MW Amplifier Design". I know Bilateral design is a good way to design LNA. Do you mean Bilateral design is a available way to design class_A PA with small signal s-pramaters?
And I need to ask you another question, at last, how do i simulate the P1dB and G1dB with ADS? or how do I know what the P1dB and G1dB is or whether the P1dB and G1dB is fit for the target?