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Öğe A 2.7-2.9 GHz Class-F Power Amplifier with 50W Output Power, %75 Efficiency and Low Harmonic Content(IEEE, 2019) Bozdemir, Suheyb; Kizilbey, Oguzhan; Yazgi, Metin; Palamutcuogullari, Osman; Yarman, Bekir Siddik BinbogaIn this paper, a 2.7-2.9 GHz class-F power amplifier with 50-Watt output power, 75% power added efficiency (PAE), 12 dB gain and low harmonic content was designed and simulated by using CGHV40050F Gallium Nitride high electron mobility transistor (GaN HEMT) and NI AWR Microwave Office v14. Realizations are planned to be made on Rogers RT5880 dielectric material which has 0.508 mm thickness and 2.20 dielectric constant.Öğe A Comparison of GaN, Si and GaAs Power Amplifiers(IEEE, 2014) Kizilbey, Oguzhan; Palamutcuogullari, OsmanPower amplifiers (PAs) are used in the wide range of electronics such as RADAR, base stations, jammers and cable TV applications. These amplifiers can achieve design specifications like high efficiency and high output power (>20W) as much as the capability of the transistor. For this reason; Si LDMOSFETs, GaN HEMTs and GaAs HFETs are advancing their place in the market. In this article; GaN, Si, and GaAs power transistor technologies will be compared and an assessment will be made about which one is leading the market by 2014.Öğe Design and Implementation of a Compact and Long Range Monostatic UHF RFID Reader with Read Point Extension(IEEE, 2014) Bostan, Ozgur; Aydogmus, Huseyin Ulvi; Topaloglu, Serkan; Palamutcuogullari, OsmanIn this paper, a compact and long range monostatic UHF (Ultra High Frequency) RFID (Radio Frequency Identification) reader has been designed for UHF RFID applications. Another circuit, called RF multiplexer, has also been designed to reduce the system implementation cost for dense antenna applications. This device has been designed in order to increase the number of antenna output ports of reader, thus enabling extended read point capability via multiple data capture. After the design process, simulation, manufacture and measurement operations has been achieved. Reader is compatible with EPC Gen2 protocol and operates at UHF band. Moreover, the reader has an antenna tuning circuit, a novel feature, to reduce reflected RF power from antennas. This is achieved by tuning output impedance of the reader to the impedance of antenna. A power detector is used to control and limit the output power to regulatory requirements.Öğe Design of 50-Watt 2-Stage Class-F Power Amplifier for Medical Applications(IEEE, 2020) Bozdemir, Suheyb; Kizilbey, Oguzhan; Yazgi, Metin; Palamutcuogullari, Osman; Yarman, SiddikIn this work, a high power high efficiency and high gain class-F power amplifier with low harmonic content was designed and simulated by using CGH40010F and CGHV40050F Gallium Nitride transistors and NI AWR Microwave Office for electromedical and radar applications. According to the simulation results, 47.5 dBm output power, 73% efficiency and 22 dB gain values were obtained in the 2.7-2.9 frequency band.Öğe Design of a Power Output Unit for HF Transmitters(IEEE, 2017) Palamutcuogullari, Osman; Ozoguz, Serdar; Aydin, Omer; Kaya, Ilker; Atasoyu, MesutIn this paper, complete power output unit for an highfrequency (3-30MHz) transmitter system is presented. The system consists of a 4: 1 power combiner block, a power control unit which is vital for the effective operation of the system and four commercially available power amplifiers. In order to achieve high-performance, we have focused on the design of power combiners and power control unit. To this end, modeling and analysis of power combiners are reconsidered and an efficient power combiner realization based on double-sided parallel-striplines is obtained. Using the proposed power combiners and the designed power control unit, the overall 1000W high-frequency output stage is built and its performance is verified via measurements results.Öğe High Efficiency Wideband Power Amplifier with Class-J Configuration(IEEE, 2018) Cagdas, Engin; Kizilbey, Oguzhan; Yazgi, Metin; Palamutcuogullari, Osman; Yarman, B. SiddikThe design and implementation of a high efficiency Class-J mode RF power amplifier (PA) for wireless communications applications is described here. In this study, a broadband class-J power amplifier with GaN HEMT transistor is designed to achieve 40 dBm output power and 10 dB gain, high efficiency and linearity performance in the 2.5-3.5 GHz frequency band. Experimental results indicate good agreement with simulations verifying and demonstrating the class-J mode operation. The obtained power added efficiency (PAE) is above 68% and the output power is 39.84 dBm at an input drive of 30 dBm. High efficiency is achieved in the frequency range from 2.5 GHz to 3.5 GHz. Simulation and experimental results show that the class-J RF power amplifier can be realized more effectively in terms of a better compromise between power and efficiency trade-offs over a significant RF bandwidth than conventional class-AB/B operations. the ACPR value for the linearity measurement was found to be around -30 dBc.Öğe Microwave Engineering Expertise in Turkey(IEEE-Inst Electrical Electronics Engineers Inc, 2018) Yarman, Binboga Siddik; Palamutcuogullari, Osman; Kaya, Ilker; Kizilbey, Oguzhan; Aksen, Ahmet; Akin, Tayfun; Ozkan, Z. Levent[Abstract Not Available]Öğe A Novel Broadband Compact 3dB 180° Power Divider/Combiner Derived From the Wilkinson Power Divider/Combiner(IEEE, 2015) Kizilbey, Oguzhan; Palamutcuogullari, Osman; Yarman, Siddik BinbogaIn this paper, a novel 3 dB 180 degrees power divider/combiner is proposed. This device is derived from the classical Wilkinson divider/combiner whose output ports were combined with inverting and non-inverting suspended microstrip lines (SMLs). The proposed structure has a reduced size compared with the conventional and enhanced variants of the 3 dB 180 degrees divider/combiner topologies. Moreover, the new architecture has a greatly improved bandwidth. The measured 0.5 dB insertion loss bandwidth is over the 2-5 GHz band for power combining/dividing. Because of its symmetrical architecture, the presented device shows frequency independent power dividing/combining balance performance. The maximum of 0.5 dB amplitude imbalance and 3 degrees phase imbalance measured over frequency band of 2-5 GHz. Measured port isolation is also about 50 dB at the center frequency.Öğe SiGe Subharmonic Mixer for Direct Conversion Receivers(IEEE, 2016) Guvenc, Umut; Palamutcuogullari, Osman; Yarman, SiddikA second harmonic mixer appropriate for direct conversion recievers is realized in 0.18 mu m SiGe technology. The realized topology offers a unique mechanism to prevent LO to RF leakage, thus, suppress the DC Offset voltage due to LO self mixing. The constant current consumption of the topology provides a proper isolation of the noise mixing operation from the supply lines. Large signal analysis of the topology is presented and the dependence of the conversion gain on the biasing conditions is investigated. Measurements are acquired to verify the conversion gain gathered from the analysis and the simulation results. According to measurement results, the conversion gain of the circuit is 35 dB and the second harmonic of LO to RF leakage is less than 70 dB.Öğe Tunable Active Front-End Realized by Using Zero-IF Down and Up Converters for to be Used in Software Defined Radios(IEEE, 2017) Palamutcuogullari, Osman; Guvenc, UmutThe proposed tunable Active BPF which is operating within 30-512 MHz band is realized by using the Zero-IF active Down and Up converters. The operating frequency of the circuit is adjusted by fixing the frequency of the LO which drives the both converters. The bandwidth of the circuit is adjusted by changing the band-width of the active Base-Band LPF which is placed between the two converters. The circuit behaves as a Low-Noise, Narrow-Band Tuned RF Front-End Amplifier with+17 dB Moderate Gain and High Selectivity. The input IIP3 is around 5dBm. A single stage NMOS common-gate balanced amplifier is situated at the input to provide the impedance matching and the sharp selectivity. The voltage-series reactive-capacitive feedback is applied to the first stage in order to raise its input impedance for the purpose of impedance matching at the input port as well as for improving its dynamic range and its bandwidth. Implemented in 0.18um CMOS process technology, a tunable, band-pass 30-to-512 MHz receiver front-end with achieves a maximum of 3.5 dB NF, +18 dB gain, +3dBm IIP3 across the operating band.Öğe Wideband Hybrid Power Combiner using Double-Sided-Parallel-Strip Lines(IEEE, 2016) Atasoyu, Mesut; Ozoguz, Serdar; Paker, Selcuk; Palamutcuogullari, OsmanA new design of a hybrid power combiner using double-sided parallel-striplines is proposed for wideband and high power applications. The circuit is used to realize a 4: 1 power combiner. The use of double-sided parallel-strip lines adds flexibility to the design, since different characteristic impedances can readily be realized by simply adjusting the offset between parallel lines, without having to change the width of the lines. Moreover, a new approach using ferrite cores in order to improve low frequency performance of the power combiner is successfully applied. The proposed power combiner is studied analytically; its performance is verified via detailed HFSS simulations and measurements results.
