In order to overcome the large size, high power consumption and low radiation efficiency of the transmitting antenna in the existing low-frequency communication system, a miniaturized and low-power low-frequency transmitting antenna is proposed. The low frequency transmitting antenna uses servo AC motor to drive the permanent magnet to rotate to generate ultra-low frequency electromagnetic wave. The upper computer sets the motion parameters of the servo motor through the programming software of motion controller, and sends them to the controller to control the motor motion in real time. The spatial modulation technology of FSK is applied to the mechanical antenna for information transmission. The experimental results show that the mechanical antenna can achieve 1bps ultra-low frequency communication with a 27.7 cm3 radiation source of permanent magnet and a low power consumption of 44W. Compared with traditional low-frequency transmitting antennas, the mechanical antenna is small in size, low in power consumption, and radiation efficiency is not limited by the Chu-Harrington limit, providing a new technical proposal for transmitting antenna of ultra-low frequency communication systems.