length of microstrip line

hi,

i am designing a microstrip patch antenna for 12 GHz using HFSS. I am using the miicrostrip line feed method to feed the antenna bbut i m nt able to determine the length and width of the microstrip line which i should use...is thr any formula available to calculate the length and the width of the microstrip line?

thanx

try this:

http://chemandy.com/calculators/micr...calculator.htm