Çakmak, Mert
Wideband RF power amplifiers are critical components in many electronic systems such as communication systems, radars and electronic warfare systems. Chip size, output power, efficiency and reliability are key points of the performance of those electronic systems. Recently, Gallium Nitride (GaN) high electron mobility transistors (HEMTs) are widely used to satisfy system requirements. GaN HEMT process provides high output power, high efficiency and reliability performance at microwave frequencies due to its wide band gap properties [1]. In this thesis, 2-6 GHz GaN MMIC driver amplifier is designed with 5 W output power and 40% power added efficiency (PAE). In this type of broadband amplifiers, undesirable performance drops can be observed because of the harmonics effect. To achieve target RF performances in the first production, matchings are modified by considering harmonics. Advanced Design System (ADS) software program is used during design. Fabrication and measurement steps are also performed. In this work, remarkable RF performances are achieved compared with similar examples.


Electrical transport in metal oxide semiconductor capacitors
Arıkan, Mustafa; Turan, Raşit; Department of Physics (2004)
The current transport mechanisms in metal-oxide-semiconductor (MOS) capacitors have been studied. The devices used in this study have characterized by current-voltage analyses. Physical parameter extractions and computer generated fit methods have been applied to experimental data. Two devices have been investigated: A relatively thick oxide (125 nm) and an ultra-thin oxide (3 nm) MOS structures. The voltage and temperature dependence of these devices have been explained by using present current transport m...
S-band hybrid 4 bit phase shifter using cots components
Erkek, Eser; Demir, Şimşek; Department of Electrical and Electronics Engineering (2009)
Microwave and millimeter-wave phase shifters are one of the most important structures of the antenna series that are used in communication and radar applications. They are used to form the main beam of the electronically scanned phase array antennas and generate the appropriate phase values for the antenna elements design while providing electronic beam steering. In this thesis, S-band hybrid 4 bit phase shifter of 22.5º phase resolution is designed, simulated, fabricated and measured. Bits are separately d...
Baştüzel Çakmak, Özlem; Durgun, Ahmet Cemal; Department of Electrical and Electronics Engineering (2022-2-9)
Radio frequency (RF) power amplifiers (PAs) are the most crucial part for the development of high performance front-end RF and microwave systems. Power transistor is the key component of a power amplifier, which should be accurately modeled to provide good correlation between simulation and measurement results. Bare die transistor needs to be packaged, before attaching on printed circuit boards (PCBs) to provide protection, easy fabrication and prevent mechanical issues. In recent years, Gallium Nitride (Ga...
Linearization of RF power amplifiers with memoryless baseband predistortion method
Kolcuoğlu, Turusan; Demir, Şimşek; Department of Electrical and Electronics Engineering (2011)
In modern wireless communication systems, advanced modulation techniques are used to support more users by handling high data rates and to increase the utilization efficiency of the limited RF spectrum. These techniques are sensitive to the nonlinear distortions due to their high peak to average power ratios. Main source of nonlinear distortion in transmitter topologies are power amplifiers that determine the overall efficiency and linearity of the transmitter. To increase linearity without sacrificing effi...
Efficient analysis of large array antennas
Ovalı, Fatih; Aydın Çivi, Hatice Özlem; Department of Electrical and Electronics Engineering (2004)
Large phased array antennas are widely used in many military and commercial applications. The analysis of large arrays containing many antenna or frequency-selective (FSS) surface elements is inefficient or intractable when brute force numerical methods are used. For the efficient analysis of such structures hybrid methods (analytic and numerical, numerical and numerical) can be used. In this thesis, a hybrid method combining the uniform geometrical theory of diffraction (UTD) and the moment method (MoM) us...
Citation Formats
M. Çakmak, “2-6 GHZ GALLIUM NITRIDE HEMT MMIC AMPLIFIER DESIGN,” M.S. - Master of Science, Middle East Technical University, 2022.