A novel uniplanar slot dipole antenna fed by a coplanar waveguide (CPW) is proposed for dual-band operation. The frequency ratio between the first spurious and fundamental modes of the slot dipole antenna can be conveniently adjusted with the use of four slot stubs introduced on its two arms. Furthermore, the radiation patterns at the first spurious mode are modified by adding four parasitic slots along its two arms to resemble those of the fundamental mode. Under the assistance of the slot stubs together with the parasitic slots, another resonant mode can be generated and merged with the first spurious mode, and therefore improve the bandwidth significantly. An antenna prototype was fabricated and measured to validate the design concept. The measured results show that dual-band operation with 10-dB impedance bandwidths of 2.99-3.83 GHz (24.6%) and 5.21-6.89 GHz (27.8%) has been obtained. The antenna has stable broadside and bidirectional radiation patterns with low cross-polarization components over the two operating bands.
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