Abstract: This paper proposes a new method of rotation speed detection based on microstrip antenna sensor. With a microstrip patch antenna and a vector network analyzer as the main components, real-time measurement of rotational speed is achieved by recording the periodic impact of rotor rotation on port return loss in the near-field area of the antenna. First, a circular microstrip patch antenna was designed and produced based on 3D printing, which provided a basis for system construction. Then, HFSS simulation was used to verify that the return loss of the antenna port changes periodically with the rotation of the rotor. The simulation results further verified the feasibility of the solution. Finally, the construction and testing of the system were completed. The experimental results showed that the system can accurately detect the rotation speed with an error within 5%, and has the advantages of anti-glare, non-contact and anti-blocking, etc., indicating the applicability of its rotation speed detection system. and reliability.