no arunmaran10 it is not like that. In microwaves electrical connection to ground doesn't mean actual grounding. Actual grounding requires via fillings all over the pcb and not just in one or two positions. In inverted F shorting is used in order to shorter the current path and in other words to decrease the resonance frequency without increasing the dimension of the antenna. That is the resonant dimension would be lambda/4 instead of lambda/2.
The inverted F "short" can be understood as a matching network using transmission line stubs. I'm not sure if the shown example is actually working, it looks way different than usual inverted F designs.