A Compact, Circularly Polarized Antenna for Human Activity Classification

In the present work, a dual feed, compact circularly polarized antenna is designed for activity classification purpose. It consists of a circular ring on the top of the substrate which acts as the radiating patch. The ground plane exactly compliments the patch and thus is a circle with radius equal to inner radius of the ring. A rectangular stub is added to the ground plane for impedance matching. The antenna has been fabricated and the measured results are in very good agreement with the simulations. Excellent circular polarization performance is observed in the antenna which is highly desirable for the intended application. The transmission and reflection co-efficient of the antenna are a function of motion activities. This is due to specific obstruction of EM waves by the antenna when involved in performing daily human activities. Datasets have been collected by actual activity performance involving the fabricated antenna. Specific and distinct signatures of S11 parameter have been obtained for different activities. Thus, the antenna can be used for activity classification purpose.