[Help] Need some documents about anten PIFA

I have a project: Design anten PIFA 2 band: 900MHz and 2,3Ghz. But, i don't know anything about this, eg: feeding Methods, formula for length, width, example...etc... I need some document or paper. I search...but have too much result and read all document is impossible. There are many way to design this antenna, i dont know what way should choose. I am beginner. I need a easy way. If any one have, plz send me. My email is: leesixan@gmail.com. Thank you very much for read this topic.

"STFW," which means in this case, "Google '900 mhz 2.4 ghz ism dual band pifa design' and then start reading."

I search...but have too much result and read all document is impossible. There are many way to design this antenna, i dont know what way should choose. I am beginner. I need a easy way. Can u help me. Thanks for interest

please reply regarding basic design factors