Fish-shaped ultra-wideband patch antenna with tilt-folded patch feed

This article introduces a low-profile fish-shaped antenna for ultra-wideband applications. The proposed antenna exhibits an impedance bandwidth of 132% (4.28 to 21 GHz) with a size of $0.199\lambda _L \times 0.256\lambda _L \times 0.092\lambda _L$0.199 lambda Lx0.256 lambda Lx0.092 lambda L (where $\lambda _L$lambda L is the wavelength at 4.28 GHz). By using a U-shaped slot and stepped arms on the upper patch, as well as a tilt-folded patch feed, four resonances are produced and then wide bandwidth is achieved. By introducing a shorting wall standing between the fish-shaped patch and the ground plane, the antenna size is reduced. The simulation and measurement results show that the antenna provides excellent performance in different bands, meaning that acceptable gain and stable radiation patterns are obtained simultaneously.