Yazar "Kahriman, Mesud" seçeneğine göre listele

Listeleniyor 1 - 6 / 6
  • Küçük Resim
    Öğe
    Analysis of rectifier stage number and load resistance in an RF energy harvesting circuit
    (Wiley, 2020) Kasar, Ömer; Gözel, Mahmut Ahmet; Kahriman, Mesud
    In this study, a single-stage and three-stage Dicksonrectifier circuits that wouldbeabletoperformRFenergy harvesting were proposed. Operating frequencywas selected as 1 GHz. The highest efficiency valuewas obtained at 7 dBm input power. The load resis-tance values for the input power were parametricallyanalyzed and the power conversion efficiency and out-put voltage were calculated. In the cases where the bestperformance was obtained, while a maximum powerconversion efficiency of 70.5% was obtained in thesingle-stage Dickson circuit, maximum 77% efficiencywas obtained in the three-stage circuit. In addition, inthe cases where the highest efficiency was observed,the load resistance values were calculated as 5590 and14 610?at the single stage and three stages, respec-tively. The load resistance value used to obtain higherefficiency values in the three-stage circuit is increas-ing. Moreover, it was observed that as the number ofstages increased, the output voltage also increased lin-early. The maximum output voltage which was 1.8 Vin the single-stage was measured as ~5.16 V in three-stages.
  • Küçük Resim
    Öğe
    Application of ultra wideband RF energy harvesting by using multisection Wilkinson power combiner
    (Wiley, 2019) Kasar, Ömer; Kahriman, Mesud; Gozel, Mahmut Ahmet
    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 2.2GHz 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, 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 BW1=0.4-0.81GHz, BW2=1.54-1.84GHz, and BW3=2.2 GHz-2.89GHz. As a power combining application, dual power inputs were applied to the WPC circuit with frequencies of 540MHz-1800MHz, 540MHz-2450MHz, 540MHz-2700MHz, 800MHz-1800MHz, 800MHz-2450MHz and 800MHz-2700MHz. Eventually, approximately 70.5% PCE and 1.65V output voltage were obtained.
  • Küçük Resim
    Öğe
    Broadband Wilkinson power divider based on chebyshev impedance transform method
    (Ceyhun YILMAZ, 2018) Kasar, Ömer; Gözel, Mahmut Ahmet; Kahriman, Mesud
    Broadband impedance matching techniques widely used in microwave circuits. In this study, weproposed a 2-way multi-layer micro strip Wilkinson Power Divider (WPD) circuit matched byChebyshev İmpedance matching technique. The design was chosen at 1 GHz center frequencyand as four layers. The design was carried out as 3 dimensions on Advanced Design tool (ADS2009) which is 3D microwave circuits’ simulation tool. For -20 dB return loss reference level,while the reflection bandwidth was 25% in the basic quarter wave matched WPD, it could beincreased up to 132% in the Chebyshev matching. Additionally, for the reference powertransmission of -4.3 dB, the transmission bandwidth raised up to %160. In the range, theproposed design could transfer 75% of the input power to both output ports.
  • Küçük Resim
    Öğe
    Design of an efficiency-enhanced Greinacher rectifier operating in the GSM 1800 band by using rat-race coupler for RF energy harvesting applications
    (Wiley, 2019) Gozel, Mahmut Ahmet; Kahriman, Mesud; Kasar, Ömer
    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 mm3 FR4 substrate material with a permittivity of 4.3 (?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.
  • Küçük Resim
    Öğe
    Investigation of the effect of RF-DC power conversion efficiency single/double layered dickson rectifier circuit using HSMS285c diode in 545 MHz to 5800 MHz GSM and ISM bands
    (TUBITAK, 2019) Gözel, Mahmut Ahmet; Kasar, Ömer; Kahriman, Mesud
    In this study, a Dickson Voltage Multiplier circuit is designed that is used RF energy harvesting technologies as rectifier topology. The efficiency analysis of these designs at different frequency and load values has been investigated. Advanced Design System (ADS) is used for design and simulation of single and double layer rectifier circuit. This layout was made using microstrip line. HSMS-285C diode is used in the rectifier layer. Rectifier efficiency, output voltage and load value that drive the circuit was investigated in single-and double-layer Dickson voltage multiplier when input power adjusted between-10dBm to 20dBm. In the single layer rectifier, 36% efficiency was observed at 545MHz and 32% efficiency at the double layer.
  • Küçük Resim
    Öğe
    A theoretical design of ultra-wideband multisection Wilkinson power divider using Euler polynomials
    (Wiley, 2020) Kasar, Ömer; Kahriman, Mesud
    When the broadband impedance matching techniques are applied to the Wilkinson power divider, it operates in a larger frequency range and covers many communication bands. In this study, an ultra-wideband (UWB) multisection Wilkinson power divider (WPD) circuit has been designed. Euler method has applied to the circuit that had equal power dividing feature on its two output ways. In the three-section of the WPD, the Euler function has been modeled as a reflection coefficient on the output branches. The Euler polynomials have been used to calculate the characteristic impedance of each section. The isolation resistors have been calculated by odd-even mode analysis according to the line impedances. In the Euler WPD, center frequency was 2.45 GHz and the limits for the return loss and isolation was selected as 15 dB and 20 dB, respectively. The bandwidth was measured as 0.75 to 3.80 GHz. The percent bandwidth of the WPD was calculated as 124.5%. Along the operation band interval, the minimum insertion loss measured lower than 0.75 dB. The design has been compared with a quarter wave (QW) WPD. It has been shown that the Euler method can achieve higher bandwidth, lower return loss and better Isolation than the conventional WPD.