Probe-fed rectangular ring antenna with a cross-strip for low cross-polarization

In this paper, a probe-fed rectangular ring with a cross-strip for wireless local-area network system is proposed. The antenna is analyzed by using the three-dimensional finite-difference time-domain method. The effects of various parameters on the characteristics of the antenna are studied. The computed and measured results for the return loss and co- and cross-polarization patterns are presented and compared. A prototype antenna operating at 2.44 GHz shows an impedance bandwidth (2:1 VSWR) of 13.06% and a gain of 9.5 dBi. Good radiation characteristics, including a cross-polarization level in both E- and H-planes greater than 26 dB and a front-to-back ratio (F/B) of radiation pattern greater than 16 dB, have been obtained.