In this letter, a new design of dual-band circularly polarized (CP) slot antenna is proposed. By embedding a vertical stub, a T-shaped strip and a slit to the ground plane, the CPW-fed slot antenna can radiate right-handed circularly polarized (RHCP) wave in two bands 3.0 GHz and 5.0 GHz. The designed antenna with a size of 33 × 27 × 1 mm3 is fed by a 50-Ohm SMA connector and fabricated on a low-cost FR-4 substrate. Experimental results show that the measured 10-dB return loss impedance bandwidths are 20.4% for the lower band and 23% for the upper band, and the measured 3-dB axial-ratio (AR) bandwidths are 14.1% and 15.8%, with respect to 3 GHz and 5 GHz, respectively.
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