Varactor diode tuning

I have designed a dual-band bandpass filter but when I fixed the varactors and tuned, the centre frequency did not change. I want it to change as per my design. is there any thing i am not doing right please?. I need to finish my thesis

Hi,

You did not show how you "did it".
Thus we can't say whether "you are not doing right".

--> show what (and how) you have done.

Klaus