Current mirror design for a Low Noise Amplifier

I am facing problem while designing a basic inductive source degeneration LNA. I fixed the gate bias of LNA for a particular current and got a noise figure of around 1dB. But when i used a basic current mirror(for the getting the same gate bias) the noise figure is increasing to the range of around 6dB. Can anyone give me clarifications for this increase?

Because you current source is noisy and it impacts the overall Noise Figure of the amplifier.There are some filtering techniques to decrease this effect coming from the current source.

Can you suggest how to filter out the noise from current source?

You have to decrese current source transconductance. The simplest way is to increase it length, but it could deteriorate your frequency response. the second easy technique is to apply a degeneration.

There are also other techniques, but more sophisticated...