linearity improvement of a LNA!!

[MK28]

hi all, i have designed a LNA , but IP3 is -15 dBm, but i want to improve it ,,,,but don't really know what is the problem of my circuit? Coould it be matching circuit, could it be biasing consdition ..or something else ?

HOw can i improved IP3?

any suggestions ....?

thanks !!

 

[pk3316]

what kind of lna you design? common gate, common source?

 

[flatulent]

Generally several things can be done

1. Increase the bias current

2. Increase the voltages

3. Use feedback. There are methods using directional couplers that do not increase the noise figure much.

4. Decrease the gain

5. Use a different transistor or if it is integrated, use a longer gate width to increase gm.

 

[kevinj]

Easy money. Degenerate it. Put an inductor below your common source. This will change your matching. So fix that after.