Usualy at this frequency (WIFI) there are ready made SAW filters. If you are a student, then try to see how looks those frequency-amplitude responses on manufacturer webpages: Murata, Epcos, Soshin, etc.
If you need to design just theoreticaly your own filter, using passive LC components, you're in trouble.
Added after 2 hours 6 minutes:
Manjunatha_hv said:
Hello,
Use Nuhertz Filter Synthesis Software to design & simulate your BPF
Unfortunately this free software is not very usefull as long will compute capacitors in femptofarad and inductances in microfarads for a 2.4Ghz band pass filter...
Do I miss something ?
I think a better option is Elsie: http://www.tonnesoftware.com/elsie.html