I have designed an front-end for zigbee applications at 2.4ghz already i had used on chip inductor(rf spiral sym) at the gate of my cs-inductor degenerated cascode lna and my nf was 2.5db but later i replaced it by the off-chip(from analoglib) one and i put the serries resistance and parallel capacitance of this inductor but my nf drops to .9db and by both of increasing and decreasing the inductor the nf increases i think this shouldn't be occured.i don't know what this happens?
i'm working by cadence rf-spectre.
have any body any idea about it?
thanks in advance.
i'm working by cadence rf-spectre.
have any body any idea about it?
thanks in advance.