Multi-polarization reconfigurable omnidirectional antenna

A new multi-polarization reconfigurable omnidirectional antenna is proposed. The antenna consists of a top-loaded monopole for vertically polarized working state (VP), a circular loop for horizontally polarized working state (HP). The circularly polarized working state (CP) is achieved by exciting the monopole and the loop simultaneously with different phases. It is shown that the bandwidth overlapped for VP, HP, and CP is about 25% (1.7-2.2 GHz) with good omnidirectional patterns.