Comparison and evaluation of various MESFET models

Altay, Mirkan
There exist various models for Microwave MESFET equivalent circuit representations. These models use different mathematical models to describe the same MESFET and give similar results. However, there are some differences in the results when compared to the experimental measurements. In this thesis, various theoretical models are applied to the same MESFET and comparison made with measured data. It is shown that some models worked better on some parameters of the MESFET, while the others were more effective on other parameters. Altogether eight models were examined and data optimized to fit these theoretical models. In using optimization algorithms MATLAB FMINSEARCH and GENETIC ALGORITHM CODE were used alternatively to solve the initial value problem.


Reliability improvement of RF MEMS devices based on lifetime measurements
Gürbüz, Ozan Doğan; Demir, Şimşek; Akın, Tayfun; Department of Electrical and Electronics Engineering (2010)
This thesis presents fabrication of shunt, capacitive contact type RF MEMS switches which are designed according to given mm-wave performance specifications. The designed switches are modified for investigation in terms of reliability and lifetime. To observe the real-time performance of switches a time domain measurement setup is established and a CV (capacitance vs. voltage) curve measurement system is also included to measure CV curves, pull-in and hold-down voltages and the shifts of these due to actuat...
Analysis and design of passive microwave and optical devices using the multimode interference technique
Sunay, Ahmet Sertaç; Birand, Mehmet Tuncay; Department of Electrical and Electronics Engineering (2005)
The Multimode Interference (MMI) mechanism is a powerful toool used in the analysis and design of a certain class of optical, microwave and millimeter wave devices. The principles of the MMI method and the self-imaging principle is described. Using this method, NXM MMI couplers, MMI splitter/combiners are analyzed. Computer simulations for illustrating the "Multimode Interference Mechanism" are carried out. The MMI approach is used to analyze overmoded 'rectangular metallic' and 'dielectric slab' type of wa...
High performance readout electronics for uncooled infrared detector arrays
Yıldırım, Ömer Özgür; Akın, Tayfun; Department of Electrical and Electronics Engineering (2006)
This thesis reports the development of high performance readout electronics for resistive microbolometer detector arrays that are used for uncooled infrared imaging. Three different readout chips are designed and fabricated by using a standard 0.6 m CMOS process. Fabricated chips include a conventional capacitive transimpedance amplifier (CTIA) type readout circuit, a novel readout circuit with dynamic resistance nonuniformity compensation capability, and a new improved version of the CTIA circuit. The fabr...
Implementation of a risc microcontroller using fpga
Gümüş, Raşit; Güran, Hasan; Department of Electrical and Electronics Engineering (2005)
In this thesis a microcontroller core is developed in an FPGA. Its instruction set is compatible with the microcontroller PIC16XX series by Microchip Technology. The microcontroller employs a RISC architecture with separate busses for instructions and data. Our goal in this research is to implement and evaluate the design in the FPGA. Increasing performance and gate capacity of recent FPGA devices permits complex logic systems to be implemented on a single programmable device. Such a growing complexity dema...
Design and implementation of microwave lumped components and system integration using MEMS technology
Temoçin, Engin Ufuk; Akın, Tayfun; Department of Electrical and Electronics Engineering (2006)
This thesis presents the design and fabrication of coplanar waveguide to microstrip transitions and planar spiral inductors, and the design of metal-insulator-metal capacitors, a planar band-pass, and a low-pass filter structures as an application for the inductors and capacitors using the RF MEMS technology. This thesis also includes a packaging method for RF MEMS devices with the use of “benzocyclobutene” as bonding material. The transition structures are formed by four different methods between coplanar ...
Citation Formats
M. Altay, “Comparison and evaluation of various MESFET models,” M.S. - Master of Science, Middle East Technical University, 2005.