UWB compact CPW-Fed circular/elliptical slot antennas with gear-shaped tuning stub

In this paper, by using circular/elliptical slots with a modified circular tuning stub and a notched ground plane, an ultra-wideband antenna is proposed. The modified circular tuning stub is gear-shaped; it can create additional surface current paths in the antenna. The notches in the ground plane is introduced to increase the bandwidth and to attain the better impedance matching. The circular slot antenna has a small size of 40 mm × 36 mm and provides a wide usable fractional bandwidth of more than 137.9% (2.5-13.6 GHz). The elliptical slot antenna has a small size of 36 mm × 34 mm and provides a wide usable fractional bandwidth of more than 131.2% (2.7-13 GHz). The simulator HFSS is used to optimize the design. Good return loss and radiation pattern characteristics are obtained in the frequency band of interest. Simulated and experimented results are presented to demonstrate the performance of proposed antennas.