Abstract: A hexagonal fractal ultra-wideband slot antenna with double band-notched characteristics is proposed. The overall size of the antenna is 32 mm×16 mm×1. 6 mm. A hexagonal and triangular iteratively nested 3rd order fractal structure is used as the radiation patch, and a defective ground structure is used as the ground plate to achieve an ultra-wide band of 3. 0- 15. 26 GHz. By introducing symmetrical L-shaped open branches on both sides of the feeder and etching the U-shaped narrow gap on the ground plate, the notch characteristics of the two frequency bands of 4. 71-5. 87 GHz and 7. 06-7. 81 GHz are generated , effectively suppressing WLAN (5.150-5.825 GHz) and the downlink satellite system frequency band (DSS: 7.25- 7. 75 GHz). The gain range in the passband band is 2-7. 5 dBi. The simulation and actual measurement results basically agree, indicating that the antenna can be used in ultra-wideband systems.