Design of reconfigurable patch antenna in frequency, pattern, and switchable polarization

In this paper, a circularly polarized frequency, pattern, and polarization switching antenna is proposed. The antenna consists of an octagonal patch, a narrow octagonal ring and four diamond-shaped parasitic patches on the top layer. Two feed points of the radiating patch are connected to a Wilkinson power divider loaded with the phase reconfigurable transmission lines on the bottom layer. Reconfiguration of the polarization and pattern is realized by using PIN diodes as switching components. By controlling the bias voltage across the varactors, various narrow frequency bands can be achieved. The proposed antenna operates at a frequency tuning range from 1.96 to 2.03 GHz. The radiation pattern can be switched among five cases in yoz-plane and xoz-plane, with the switchable polarization between left- and right-hand circular polarization. In addition, these three types of reconfiguration can be controlled independently.