Inset fed patch antenna properties development

[yefj]

Hello,in patch antenna there is a trick where we do inset feedind by carving away frm the patch to do matching.
i used to design just by playing with the dimentions.
what is the physics behind the mechanism of this?
Thanks

 

[vfone]

Antenna-Theory.com - Rectangular Microstrip (Patch) Antenna - Feeding Methods

Feeding methods (method for driving power to the antenna) are introduced. The direct feed, the inset feed, the aperture feed and the coupled or indirect feed are presented for microstrip antennas.

www.antenna-theory.com