An amplitude modulation method of the mechanically-rotating based antenna

This Letter presents an amplitude modulation method of the rotating-based mechanical antenna that does not require the change in the rotational speed of the permanently polarised material as in frequency modulation, hence overcoming the mechanical design challenges. A mechanical-based modulator is designed to control the attenuation of the radiation field in specific polarisation direction, and the signal reception in different polarisation directions is realised by using two-axis orthogonal coils. The underlying physics is discussed and simulated using the basic electromagnetic theory, the design of transmitters is described, and a prototype is built to verify the effectiveness of the modulation method.