Guide lines for designing RF power amplifier

[bhagavanec67]

Hello every body,


I am new to both EDA board and RF. I want to know the factors to be considered while selecting an Amplifier for a particular application.

While discussing with my friend I am eager to design a my own power amplifier.So, I am requesting to guide me to do this with your valuable guide lines. please provide any links avialable.

Thanking you every body,

Regards,

Bhagavan

 

[davenn]

hi there Bhagavan

welcome to the forums

your query is pretty vague and as a result a suitable answer cannot really be given

how about elaborating a bit more... like an amplifier....
centred on what frequency ?
what bandwidth?
What input power will you feed it with?
What output power level do you wish to obtain?
Do you have the relevent licences to transmit on the frequency you are interested in ?
Do you have the relevent test equipment to determine output power, cleanliness of the signal etc?

you need to be able to answer all those initial questions so that you may get as least helpful answers
If you are a beginner in RF, you may have to consider that a project like this is out of you depth at the moment
and you need to spent more time working on more basic projects to gain some experience

cheers
Dave

 

[bhagavanec67]

Thank you for giving reply. Its my own interest to design it.As i gone through the books about the amplifier I thought that it will be better if do it parallel. as you said its a difficult task for a beginner and need to know more basics about it. so I want those.

I want to design an Power amplifier with frequency range 0.5GHz-2GHZ. with a gain of 10W. but I am unable to fix the other parameters like Dynamic range of Input power, biasing etc Please help me on this aspects.

Thanking you once again for your quick reply.

 

[davenn]

ok that's a little more info

a gain of 10W doesnt mean anything

We say an amplifier may have a gain of 10dB, so for example, if we input 1Watt, we get 10Watts output
or it has a gain of say 20dB, if we input 100mW ( 0.1W) we will get 10W output

so what is the transmitter you intend to power this amplifier with ?
does it really have a range of 500MHz to 2GHz ?, or are you just going to use a signal generator ?


500MHz to 2 GHz is a very broad bandwidth,
To use discrete transistors it would be quite difficult, it is doable with various Motorola ( now Freescale) power block modules. They take care of all the variations of freq Vs impedance problems assoc with broad band transmitters
They have ones they make for the CATV ( cable TV) market
You MUST define input power, that is essential, as that is going to determine which module is suitable for your application

and as I asked earlier .....
Do you have the relevent licences to transmit on the frequency you are interested in ?
Do you have the relevent test equipment to determine output power, cleanliness of the signal etc?

those are also essential, specially if you intend transmitting 10W of RF. The last thing you want is for the authorities knocking on your door and confiscating all your gear and slapping you with a huge $$ fine for a dirty and illegal transmitter

Dave

 

[Ow@i$]

As i can see you are newbie in this field ... and straight away going for such a wide band... it is not a good option, as you will encounter matching issue over this band... which requires wide band matching, thus more complications!! Moreover Transistor in this range would not be easily and cheaply available... if it is just a interest then pick some VHF range amplifer..100-200 MHz
10 Watt power 1 watt input....!!! search nxp , freescale for your transistor that match these parameters, download its design file.. Install ADS and starts working... i am attaching a helpful starting doc!!! Once you make one amplifier you will have confidence and required expertise to design a more comlex one!!

View attachment 5989-9594EN.pdf

 

[freegen]

will this work for just making 10w rf waves? what kind of antenna do you use?

**broken link removed**