Coplanar waveguide possesses the advantage of lower loss and being easier to be integrated with other circuits comparing with the microstrip line. However, the bandwidth of the fed rectangular monopole antenna of the conventional coplanar is narrow. To broaden the bandwidth, the patch is notched on the bottom, and the central strip of the coplanar waveguide is prolonged to the groove top for feed. Both of the edges of a part of the coplanar ground and the groove top followed gradual regularity, and a ladder configuration is inserted into the groove to adjust the input impedance. Simulation indicates that the fractional bandwidths of the antennas can be broadened from 84.8% to 167.2%（a coverage of 2.17~24.3 GHz,S11≤-10 dB）in this way. The measured results agree well with the simulated ones. The radiation pattern of the antenna is nearly omnidirectional, which can be used in portable UWB communication systems.〖JP〗