In this letter, a new compact ultrawideband (UWB) antenna with band-notched characteristic is proposed for UWB communication applications. By using a C-shaped ground, the overall dimension of the proposed antenna is dramatically decreased to 24 × 28 × 1 mm3. To avoid potential interferences, interdigital capacitance loading loop resonator (IDCLLR) is utilized to reject certain bands within the passband of the antenna. Due to its high capacitance, the resonator has a smaller size and forms a narrower notched band than many other structures, thus the present design effectively saves many more useful frequencies. Good agreement is achieved between the simulation and measurement, which shows that the proposed antenna has an operation frequency band from 3 to 13 GHz with good rejection to the wireless local area network bands (WLANs) (5.2- and 5.8-GHz bands).