Flexible Circular Sector Microstrip Patch Antennas for Mechanical Bending Sensing

A flexible circular sector microstrip patch antenna (MPA) for mechanical bending sensing is proposed. The central angle alpha and the radius R serve as two degrees of freedom in sensing. Unlike tradition rigid sensing antenna, the proposed antenna can be bent and attached conformally to the surface of various objects, such that the deformation degree can be mapped into the variation of resonant frequency. In that way, the sensing antenna can be used as a tag in radio identification (RFID) systems for stretching and bending detection of motional objects. The effects of alpha and R on sensing sensitivity of the antenna have been numerically simulated and experimentally tested. As can be seen, a larger central angle alpha may yield higher sensitivity in distinctive bending schemes.