LNA gain range is not wide? ?

[shanmei]

I hope my LNA gain v.s. frequency like in the figure 1, which has high gain over large frequency range. However, my gain is only in a very narrow region as in the figure.

Can anyone help ? Thanks.

 

[BigBoss]

There are many frequency selective circuits ( TLs,Caps etc) therefore your LNA is a narrowband one.
What you were expecting ??

 

[FvM]

The circuit schematic doesn't show the apparently existing resonant structures. You need to eye the whole picture, element parasistics, bond wires (are they actually modelled?), external circuit.

 

[chuckey]

Are you terminating your measurement cables correctly?
Frank

 

[shanmei]

There are many frequency selective circuits ( TLs,Caps etc) therefore your LNA is a narrowband one.
What you were expecting ??

I want to 3dB bandwidth is 10GHz

- - - Updated - - -

Are you terminating your measurement cables correctly?
Frank

It is just simulation

- - - Updated - - -

Thanks. I don't include the bondwire. I just simulated as in the figure schematic.

When I increase the inductors at the sources of T2 and T4, the gain is increased and the bandwidth is decreased.