what is the criteria to set the grnd plane

hello
this time i want to ask about the criteria of setting the dimension of ground plane in microstrip antenna.
in mostly papers dimension of grnd plane is not given so i want to ask that how can i calculate the dimension for grnd plane if it is not given in the research paper.
my another question is what is the furmulae for calculating the bandwidth of microstrip antenna

The return current is beneath the strip, take your GND plane width 5 times (height+width) of strip and you cant go wrong

i m not able get u by "strip". what do u mean by strip plz elaborate.
if the length=53 and width=79 of microstrip antenna then what should be the ground plane.

regards sameer

strip=track=trace