In this study, an ultra-wide band (UWB) energy harvesting circuit was proposed using the Greinacher rectifier circuit. The circuit was designed with Wilkinson power combiner (WPC) for use at two different radio frequency signal inputs. To enable broadband operation, the multisection Chebyshev impedance matching technique was applied in the branches of the WPC circuit. The center frequency was selected 2.2 GHz in the design. In terms of the parameters of reflection, transmission and isolation, the WPC circuit operates in the 0.4 GHz-3.4 GHz range and the percentage bandwidth has been calculated as 136%. In the designed Greinacher rectifier circuit, power conversion efficiency (PCE) was analyzed for different input powers. When load resistor selected as R = 1500 Ω, the PCE for the input power of 9 dBm was about 70%. The proposed circuit, where WPC and Greinacher rectifier circuits was used together for energy harvesting; was operated in the frequency ranges BW 1 = 0.4-0.81 GHz, BW 2 = 1.54-1.84 GHz, and BW 3 = 2.2 GHz-2.89 GHz. As a power combining application, dual power inputs were applied to the WPC circuit with frequencies of Eventually, approximately 70.5% PCE and 1.65 V output voltage were obtained.

In this study, a single‐stage and three‐stage Dickson rectifier circuits that would be able to perform RF energy harvesting were proposed. Operating frequency was selected as 1 GHz. The highest efficiency value was obtained at 7 dBm input power. The load resistance values for the input power were parametrically analyzed and the power conversion efficiency and output voltage were calculated. In the cases where the best performance was obtained, while a maximum power conversion efficiency of 70.5% was obtained in the single‐stage Dickson circuit, maximum 77% efficiency was obtained in the three‐stage circuit. In addition, in the cases where the highest efficiency was observed, the load resistance values were calculated as 5590 and 14 610 Ω at the single stage and three stages, respectively. The load resistance value used to obtain higher efficiency values in the three‐stage circuit is increasing. Moreover, it was observed that as the number of stages increased, the output voltage also increased linearly. The maximum output voltage which was 1.8 V in the single‐stage was measured as ~5.16 V in three‐stages.

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 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 1850 MHz was designed. Then, at this frequency, designing of the rat-race coupler having 1000 MHz 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 × 70 × 1.6 mm 3 FR4 substrate material with a permittivity of 4.3 (ε r = 4.3). The power conversion efficiency (PCE) of the rectifier circuit, which had 125 MHz bandwidth at the center frequency of 1850 MHz and was developed with rat-race coupler, was calculated as 71% at 4.7 dBm input power. In addition, with this study, at −15 dBm input power, which was a relatively low power level, 40% PCE value was obtained. K E Y W O R D S180 hybrid ring (rat-race) coupler, Greinacher full-wave rectifier, high efficiency rectifier topology

Herein, it is aimed to design an Active Frequency Selective Surface (AFSS) based high performance reconfigurable filtering antenna (Filtenna). The proposed AFSS unit element is consist of a single PIN diode with a simple microstrip patch design which performance characteristics are varies with the state of the diodes. The proposed unit elements have been used to form an array that is placed at the aperture of a double ridge horn antenna. With the variation in state of diodes, the antenna acts as a Filtenna module to filtering the incoming electromagnetic waves in frequency band of 1.8 to 2.8 GHz. From the experimental results, it is shown that the proposed Filtenna achieves a signal attenuation of 7.3 dBi at 2.1 GHz.

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