A Polarization-Reconfigurable High Gain Microstrip Antenna

A novel polarization-reconfigurable cut ring microstrip antenna with high gain is proposed. This simple structure microstrip antenna consists of a ring radiation patch, two switches (p-i-n diodes), and six nonmetallic columns. By controlling the switches, the antenna can be operated on three polarized states: one state for linear polarization (LP), one state for left-hand circular polarization (LHCP), and one state for right-hand circular polarization (RHCP). In addition, the antenna peak gain can reach 10.0 dB for LP, LHCP, and RHCP over the operating bandwidth and stable unidirectional radiation patterns. The proposed antenna is fabricated and verified. By analyzing simulated and measured results, the measured common operating bandwidth of the proposed antenna on three states is from 3.86 to 3.98 GHz with the relative bandwidth of 3.1%. The cross-polarization of the antenna on the whole states is very low. Good polarization-reconfigurable characteristics of the proposed antenna have been obtained from 3.86 to 3.98 GHz. The proposed antenna is also a good candidate for advanced wireless communication systems.