The electromagnetic resonance technology is working based on the communication between electromagnetic signal released by the digital pen and antenna board. When the distance between the pen tip and the tablet surface, or antenna board, fall within the sensing height, circuits on the antenna board would respond to the movement of the pen. Magnetic flux of the integrated circuit on the antenna board would therefore vary as signal captured by the antenna array changes, and then coordinates of the pen would be calculated and reported accordingly. Besides, as there is an inbuilt pressure sensor in the digital pen that is responsive to vertical pressure, signal released by the digital pen would vary as pressure applied changes, and the antenna board would react correspondingly to release signal that enables movement of the pen and pressure applied to be rendered organically as lines of various shapes and saturation on the screen, which is very critical for reproducing the original handwriting of users.