I have a menu item in action bar. Which always looks small as in below image.

I want its size to be approx. double of this. I have put different sized icons in mdpi, hdpi, xhdpi folders. Thus, it is not a dpi related problem.
I have this issue in HTC One and emulator which is xhdpi. I tried enlarging icon in xhdpi folder and tested in emulator, but no change in its size in action bar. For micromax canvas2(hdpi) it works fine.
Is there any way to set menu item's size to fix height and width? Or any other workaround?