A compact novel dual band antenna with unidirectional radiation pattern is presented. The proposed antenna consists of radiating patch with linearly tapering. To generate first band, the authors use a rectangular slot on the radiating patch. In addition, by introducing feed-line asymmetry, a dual band function is achieved. By linearly tapering the radiation patch, significant improvement in gain is observed. The dual band antenna achieves a unidirectional radiation pattern at all the two frequency bands with an antenna gain of 3.1 dBi for the first band and 4.2 dBi for the second band. This antenna has compact size and reasonably high gain, suitable for various applications. The antenna is simple in structure with very few design parameters.