This lecture describes the charge distribution and current density creation on microstrip patch. Further, through this lecture we can understand the equivalent current densities on four side walls of rectangular microstrip patch. You can understand why only the TM field configuration exist in rectangular microstrip antenna. The above analysis is based on the cavity model analysis.
The contents of the lecture is taken from the popular book: C.A. Balanis, “Antenna Theory: Analysis and Design,” John Wiley & Sons, Inc., New Delhi, 2005.
