This paper presents the design of thin planar one-sided directional slot antenna on patterned circuit board. Our proposed planar antenna has the matching circuit composed of coplanar waveguide (CPW) transmission line, interdigital gap, a top metal layer and a bottom floating metal layer. In order to realize the one-sided directional properties, the length of the top metal layer is adjusted, and at that time, the bottom metal layer is adjusted to the length that doesn't resonate. The final antenna size of the 300MHz specified low power wireless receiver is 137mm x 61 mm. We also fabricated the one-sided directional slot antenna using FR4, and measured the radiation pattern.