Abstract: A novel ultra-wideband notch antenna is proposed. To obtain the notch in the WiMAX frequency band, high-impedance surface（HIS） elements are loaded on both sides of the feed line of the ultra-wideband microstrip monopole antenna. The unit size reduces 55.2% compared with the traditional structure, which etches Archimedean spiral structure gap on the high-impedance surface. To further realize double notch in WLAN and WiMAX frequency bands, asymmetric novel HIS elements are loaded on both sides of the feed line of the microstrip monopole antenna. The measured and simulated results are in good agreement, which proves the feasibility of the new notch unit cell.