In this work is proposed a high efficiency Radio-Frequency (RF) Energy Harvesting (EH) system that takes uses of the Portuguese Digital Television (D-TV) signal to obtain DC power. To be useful, the system is optimized to operate at low power conditions. For the rectifier, three different solutions are presented: a single-series diode, a shunt-diode and a voltage doubler configuration. The efficiency is similar for the three rectifiers – around 54% with a sine-wave excitation and -10.5 dBm input power. Field measurements with the voltage doubler has proven 63% efficiency for the same input power. As receiver antenna is proposed a slotted patch with a stacked parasitic (based on FR-4 substrate) that results from the need to improve the bandwidth (BW) of the basic microstrip patch.