A novel dual-band circularly polarized monopole antenna fed by coplanar waveguide (CPW) is proposed. Deformed monopole and asymmetrical ground are utilized to achieve dual-band characteristic, by adjusting the tuning stub close to the deformed monopole, the antenna can be further improved to a good performance. Measured results show that the proposed antenna impedance bandwidth is 1.44 GHz centered at 3.42 GHz for the lower band and 400 MHz centered at 5.2 GHz for the upper band, the 3-dB axial ratio bandwidth is 900 MHz centered at 3.25 GHz and 400 MHz centered at 5.1 GHz respectively. The measured results agree well with the simulated results.
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