Wideband zeroth-order resonance antenna combined with TM010 mode having folded mushroom structure

In this paper, a wideband folded mushroom antenna which operates from a zeroth-order resonance (ZOR) mode to a TM₀₁₀ (λ₀/2) mode is presented. By folding a mushroom structure, the TM₀₁₀ mode is down-shifted toward the frequency of the ZOR mode and, thus, the wideband is achieved without any additional structure. The optimized antenna has a dimension of 0.365λ₀ × 0.247λ₀ × 0.182λ₀ at the center frequency. As a result, a 10dB fractional bandwidth is measured to be 68.3% which ranges from 2.38 GHz to 4.85 GHz. Moreover, the measured radiation efficiency is above 80% in the whole band. The measured result shows a good agreement with the simulated result.