Radio frequency energy harvesting (RFEH) circuits can convert the power of communication signals from radio frequencies (RF) in the environment into direct current and voltage (DC power). In this study, the Greinacher full-wave rectifier circuit topology was combined with a 180 degrees hybrid ring (rat-race) coupler which was a passive RF/microwave circuit. Thus, higher RF-DC conversion efficiency was obtained. First, using the Greinacher rectifier topology, RFEH circuit operating at the center frequency of 1850MHz was designed. Then, at this frequency, designing of the rat-race coupler having 1000MHz bandwidth was made. The S-parameter measurements and simulation data of the designed coupler circuit were compared. Finally, the high efficiency rectifier circuit where these two circuits were used together was designed. The proposed rectifier circuit was constructed on 70 x 70 x 1.6 mm(3) FR4 substrate material with a permittivity of 4.3 (epsilon(r)=4.3). The power conversion efficiency (PCE) of the rectifier circuit, which had 125MHz bandwidth at the center frequency of 1850MHz and was developed with rat-race coupler, was calculated as 71% at 4.7 dBm input power. In addition, with this study, at -15dBm input power, which was a relatively low power level, 40% PCE value was obtained.