In general, modes are designated as TMnmp. The ‘p’ value is mostly omitted because the electric field variation is considered negligible in the z-axis since only a phase variation exists in the z axis. So, TMnm represents the field variations in the x and y directions.
The field variation in the y direction (impedance width direction) is negligible and m is 0. The field has one minimum-to-maximum variation in the x direction (resonance length direction and a half wave long), n is 1 in this case and we say that this patch operates in the TM10 mode.