What is the theoretical procedure of getting equivalent transmission circuit model of any complex geometries (patch or monopole antennas) and their formulas........
The circuit model can be designed with concepts from papers or books. But the LC parameters can be extracted by curve fitting method as only a few equations are available. This paper will be helpful.
Yuandan Dong, Hiroshi Toyao, Tatsuo Itoh, Life Fellow, "Design and Characterization of Miniaturized Patch Antennas Loaded With Complementary Split-Ring Resonators", IEEE TRANSACTIONS ON ANTENNAS AND PROPAGATION, VOL. 60, NO. 2, FEBRUARY 2012.