Compact Tri-Band Dual-Polarized Planar Monopole Antenna With Asymmetrical Ground Plane and Loaded Stub

Abstract

Abstract-This paper presents a compact tri-band dual-polarized planar monopole antenna, which is linearly polarized in the lower and middle bands and circularly polarized in the higher band. The antenna is printed on a substrate with an asymmetrical ground plane and a loaded vertical stub. The vertical stub and asymmetrical ground plane are mainly used to make the antenna obtain circular polarization performance in the higher band. The antenna has been built and tested. Its measured 10-dB impedance bandwidths are 2.39-2.54 GHz, 3.38-4.12 GHz, and 4.57-6.04 GHz, which can fully cover all the 2.4/5.2/5.8 GHz WLAN bands, all the 2.4/5.5 GHz Wi-Fi bands, and 3.5/5.5 GHz WiMAX bands. In the higher band, the measured 3-dB axial-ratio bandwidth is 5.4-5.83 GHz.