Effect of phase fluctuation at high speed of smart gear on return loss of receiver antenna

This research evaluates the influence of phase fluctuation of a high-speed smart gear on the return loss of monitoring antenna in our developing “smart gear sensor system”. This smart health monitoring system of gear comprising of an antenna connected to a network analyer and another similar antenna integrating crack detection sensors directly printed on a gear. The principle of this system is based on magnetic coupling phenomenon between samples of antenna and crack detection sensors with antenna printed on polyacetal (POM) plates so that the characteristics of the gear side elements can be obtained wirelessly. In this paper, the effect of the relative phase fluctuation when the smart gear is operating at high speed on this coupling signal perhaps is considered. Practically, a special experimental rig consists of a motor with a speed control button, an antenna on a polyacetal (POM) plate with a radio frequency connector, and a smart gear with integrated sensors antenna was created. Thanks to this test rig, the smart gear is able to rotate with variant rotational velocities in range of 500 rpm to 5000 rpm while keeping pairing concentrically with the fixed monitoring antenna at a constant distance. Then, return losses received from this antenna via the network analyzer then are recorded at each specific speed. In comparison with the return losses gained in case of similar experimental setting but in stationary state, the shape form of the high-speed phase fluctuation return loss is indicated.