Bro. I made the antenna by 3.1 cm (length of unshielded portion). But the problem now face is when i checked(multi meter on circuit check mode)the ground and main connection where i have to solder the antenna the multimeter is showing that there is connection between them(multi meter is buzzing). Is that normal???
Or is ther any problem with internal connection of transmitter?
That is perfectly normal. - using a DC meter , it will read low resistances b/w the gnd and antenna pad of a rf module , close to few ohms.
But actually it's the measuring method which is wrong , an RF or antenna feed is AC. DC measurement systems are of no use here .
The same ground and antenna pads that your multimeter thought are short circuited , might read 10's of ohms of impedance at 2.4Ghz (that is when measured with the proper equipments! , Your DC resistance measuring device will still show a short circuit !! ).
So don't worry about it , put it back , make sure to solder properly and do a range test (ground and air) before you fly out in the open .