about inductor?

what about it?

when u say "in the emitter" do u mean the inter-elemental or inter-electrode inductance?

do u have a schematic? posting a schematic might help

Can be many things ...

It can come from the parasitic inductance of via's in a pcb. You see this kind of stuff a lot in application notes. That's an unwanted side effect.

It can be useful too. The series inductance can have positive effects on the noise figure. Because it brings the optimum noise match and optimum power match points at the input of the transistor closer together. Check this out:
hxxp://rfdesign.com/mag/radio_unique_inductive_feedback/

the inductor in the emitter is often used to provide degenerative feed back to the transistor and is also used to obtain a simultaneous impedance/Noise match