A high-impedance wideband folded dipole antenna (FDA) has been designed for energy harvesting applications. High impedance is necessary for producing high efficiency rectennas. An impedance of over 300 Omega can be achieved by FDAs due to the impedance step-up function. The wideband design is introduced theoretically using an equivalent circuit for the FDA. A bandwidth over 20% with a characteristic impedance of 350 Omega was achieved. Measurements of the fabricated antenna are compared with the results of simulations and the high-impedance wideband design is verified.