A pad-less 5GHz RFID employing complementary pass-transistor adiabatic logic is proposed. The power clock that drives the whole CPAL is improved to enable a smaller input RF power and higher speed data frequency by using a power clock shaper which pulls the power clock to GND when a falling edge is detected. Additionally, a new CPAL circuit exploiting both the threshold voltage and W/L of the transistors is proposed. Measurements confirm that the proposed RFID can communicate at a distance of 11cm with 12dBm transmission power, as well as at a 100kbps data rate across a distance of 1cm.