In this paper, a new planar antenna is proposed for ultra-high frequency (UHF) band applications. The proposed antenna fed by conductor-backed coplanar waveguide (CBCPW) is based on the monopole antenna with a triangular patch. To achieve wideband characteristics, a notch cut and steps are added to a regular triangular patch. To further broaden the bandwidth, slopes are given to both the upper and lower ground planes of the CBCPW feed. The proposed antenna was optimized by adjusting the distance between the patch and the ground plane, the outer length and width of the ground plane. Experimental results show that the -10 dB return loss bandwidth is 2,610 MHz from 450 MHz to 3,060 MHz (6.8:1 ratio bandwidth). Within the entire operating frequency range, the measured average antenna gain is 4.24 dBi in the E-plane. Thus, the proposed antenna covers all the frequencies of the UHF band communication systems.