A Wideband Folded Dipole Antenna With Stable Radiation Patterns Under Multi-Resonant Modes

A novel wideband folded dipole antenna (FDA) with stable radiation patterns under multi-resonant modes is proposed in this communication. First, by lengthening and widening the driven strip of a folded dipole antenna, the input resistance of its 1 st - and 3 rd -order modes declines significantly. Second, the driven and non-driven strips are further widened at a fixed ratio to achieve better impedance matching. Third, a pair of open-slot loops (OSLs) is advisably added to compress the resonant frequency of the 5 th -order mode close to that of the 3 rd -order mode for bandwidth improvement. Finally, a prototype is fabricated to provide experimental verification of the idea, and measured results show that the proposed FDA has a bandwidth of about 82% from 1.72 to 4.10 GHz, which exhibits a good agreement between measurement and simulation. In particular, the proposed FDA obtains stable radiation patterns in the entire operating band.