A single-feed wideband CP antenna with stacked square slotted-microstrip configuration is proposed for RFID applications. As shown in Fig. 1, the proposed antenna consists of a main patch, a stacked patch, and a feeding probe. A cross-shaped slot and a square-shaped slot are cut into the square radiating patch and the stacked square patch, respectively. The CP radiation is generated by the embedded cross-shaped slot in main square patch along the diagonal line. The area and location of the embedded slots as well as the separation between the patches (h2 + h3) on are optimized for a wideband CP radiation. Good impedance matching over the desired band is achieved using microstrip stub and feed location on the microstrip stub. The design and optimization of the proposed antenna was conducted using the commercial software CST Microwave Studio. The measured 10-dB return-loss and 3-dB axial ratio bandwidths of the antenna prototype are around 165MHz (840 MHz-1005 MHz) and 105MHz (855 MHz-960 MHz), respectively. The gain is around 7.0 dBic across the 3-dB axial ratio bandwidth, while overall antenna volume is 0.54λo × 0.54λo × 0.087λo (where, λo is free space wavelength at 900 MHz).