Self-excited dynamic active antenna

Proposes the self-excited dynamic active antenna (SDAA) that can detect a contact location between an insensitive flexible beam and an object through observation of the fundamental natural frequency of the beam in contact with the object. The main, part of SDAA is composed of a flexible beam, one permanent magnet and two electromagnets not only for producing the exciting motion but also for changing the boundary condition of the beam. We show that the contact position is uniquely determined by utilizing the fundamental natural frequencies before and after changing the boundary condition. We present the basic working principle of SDAA and show some experimental results to verify the idea