Dual-band reconfigurable circularly polarized monopole antenna
A microstrip antenna with dual-band reconfigurable circular polarization (CP) characteristics in Wireless Local Area Network (WLAN) and Worldwide Interoperability for Microwave Access (WiMAX) bands is presented in this article. The proposed antenna has a symmetrical U-shaped slot with PIN diodes on the ground plane. The slotted ground generates a resonant mode for broad impedance-band width, and excites contrary CP state at 2.45 GHz for WLAN and 3.4 GHz for WiMAX, respectively. Because switching the states of PIN diodes on the slot can redirect the current path, the CP state of the proposed antenna can be simply switched between the right-handed CP and left-handed CP. The proposed antenna has a low profile and a simple structure. Measured results of the fabricated antenna prototype are carried out to verify the simulation analysis.  2014 Wiley Periodicals, Inc. Int J RF and Microwave CAE 25:109114, 2015.
monopole antenna circular polarization reconfigurable antenna