differential antenna design

I need to design a differential antenna. Any one know how design PCB differential antenna, formulas and relevant papers? Thanks

May be this helps you
http://www.vlf.it/cr/differential_ant.htm
http://www.freepatentsonline.com/7123209.html

loops and dipoles are your friends.

I have a MCU with different output (100 Om) to antenna, so i want to design different antenna (with different feed) using PCB track to eliminate using lumped RF components (which are hard to find for me).
My question are:
1. how do we calculate the dipole width.
2. dipole's fed using ordinary PCB track or must be in form microstrip line (have ground plane).
3. what size is the gap between dipole arms, and how does it affect antenna.

i"ve read a lot papers but still in confusion. Any help is highly appreciated
Thank in advance.