need help for my LNA project!!plz!!

[dia_bo_lique]

lna project

I am designing a LNA using a BF998 dual FET with an operating frequency of between 137MHz - 138MHz,and gain: 15-20dB.I am using Electronics Workbench Multisim 9 software to simulate the frequency response of the circuit.The problem is..I have been tweaking the values of the LNA circuit but so far unable to produce anything even remotely close to the required frequency response(similar to a bandpass filter response->designed to pass frequencies bet. 137MHz-138MHz,reject all other freq).Can some1 plz take a look at my circuit I have attached n tell me wuts wrong with it?or maybe if u can suggest the appropriate values..I would appreciate ur help tremendously.plz!!any1!![/img]

 

[vfone]

bf998 at 1v

Seems that your circuit is oscillating around 60MHz.
Try to change the input and the output match, use an RF choke instead R4, and try to avoid using that BPF at the output (LP input match and HP output match should be fine getting decent bandwidth).

 

[Abhishekabs]

Also You can try by placing choke at gate input i.e at position(4) in your schematic.
Have you Entered all parameters of transistor
BF 998 in simulator?
Such as Eg, Vto etc.?
Please check your Model.