Variational method for analyzing microstrips

Can anybody tell me about the variational method which is used in analyzing of differnt types of tranmission lines ,i particularly want for equations and method for microstrips?any link will be very helpful

variation method for analysis microstrip antenna:
1- cavity model
2- transmision line
3- full wave
you can refer to book antenna theory by balanis chapter14 (microstrip antenna).
this book available is in link:

http://betah.co.il/BookDetails.aspx?...alanis&id=1178

look up in Collin's Field Theory of Guided Waves. I probably read from it getting issues from Library. Can someone give link for this classic reference

you can download this book from links:

http://mihd.net/y1sm0c