Help need in Class A Microwave transistor Power amplifier design in ADS at 18-26 GHz

[asimshakoor]

Hello,
I have to design Class A microwave power amplifier for Ka band.
I need help in it. I need to know the step by step method for this. I have seen the books but i got confused, as there is no step by step methods. Can any one help me?

 

[Ow@i$]

a lot of steps there are actually!!! first install ADS i recommend , it is a perfect tool for such projects!!!
then you must search out online dealers like Nxp, Freescale etc for the transistor that can work on Ka band as amplifier!! BTW how much output power do you need???

 

[asimshakoor]

a lot of steps there are actually!!! first install ADS i recommend , it is a perfect tool for such projects!!!
then you must search out online dealers like Nxp, Freescale etc for the transistor that can work on Ka band as amplifier!! BTW how much output power do you need???

Thanks for the answer.
I have ADS installed.
Required output is: Min. IP3 40 dBm, P1dB 35 dBm

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Thanks for the answer.
I have ADS installed.
Required output is: Min. IP3 40 dBm, P1dB 35 dBm.
I am also given some transitors models in ADS and out of which i have to select one and then design amplifier circuit. But i dont know much about ADS and step by step procedure of amplifier design. I need help in this.

 

[Ow@i$]

You will know as you play with different options, Follow the attached Document.
Since you have different models installed .. so simulate and then chose the most optimum!!!

 

[BigBoss]

For 18-26 GHz A-Class amplifier, you can not work with ordinary semiconductor companies such as NXP, Freescale..
If you have never designed an amplifier, to be honest forget this project.Eventough you designed some try-outs to learn something, it's really really hard for you and it needs so high experiences on amplifier design and layout.Because there is neither discrete bipolar nor discrete fet transistor working in this band with these output level and linearity (maybe few with lower specs.) .You have to work with some specialized foundries like Triquint,M/A-COM or Hittite etc. but there are many technological restrictions for some countries.
However good luck..

 

[asimshakoor]

Hi, thanks for the reply and the file. I will read it.
I have one question. As we know that the amplifier gain decreases with frequency because of the (1)internal capacitances Cds and Cgd and (2)miller effect. At the particular frequency fo, i can get the desired gain and output power. But if i want to design an amplifier to get constant gain for the whole frequency band of 6GHz centered at fo, then what method shall i use?

 

[Ow@i$]

The thing that plays the major role in achieving constant gain over the band is your impedance matching. What you need is broad band matching that will surely ensure a constant gain over the desired designed band , rather on just and around fo!!

Follow this doc it elaborates quite greatly the issue of broad band matching: