Suayb Cagri Yener

Algorithms on the extraction of BSIM MOSFET model parameters via measurement data

In this paper, parameter extraction algorithms are designed from the BSIM3v3 MOSFET model equations. The solution codes for the equations are written by MATLAB. The algorithms are designed to give results from only devices characteristics data. BSIM MOSFET model parameters are extracted by these algorithms. The SPICE simulations are performed using extracted parameters also. Simulation results have been compared with real measurement data. Hence, the work is finalized by determining the model performance and its accuracy.

A process control method for the electric current-activated/assisted sintering system based on the container-consumed power and temperature estimation

In this paper, the current, voltage and temperature of the container of an electric current-activated/assisted sintering (ECAS) system are measured and recorded with respect to time during the sintering process. By post-processing of the recorded data, the power and thermal energy of the system container are calculated. Interpretation of the measured and post-processed data has provided a criterion: It has been found that the dissipated electrical power in quasi-steady state is almost equal to the power conducted from the container to the copper bars throughout the stiffs and the convection and radiation powers are negligible compared to the conducted power. Therefore, the container-stored thermal energy or the container surface temperature can be estimated from the dissipated electrical power with the values of the container heat capacitance and the stiff thermal resistances without the need for a temperature measurement equipment. If the thermal energy or the temperature required to make the samples has a known/required minimum value and if this amount of the thermal energy is provided to the sample, the sample production process can be stopped. In this study, for an actual implemented design, we suggest that ECAS current and voltages should be continuously measured in real time and the process is automatically terminated when the calculated steady-state container temperature becomes equal to the required container temperature. Therefore, a standard procedure for material production in ECAS system is provided to automate sample production and the performance of the produced samples is guaranteed.

Memristor-based timing circuit

Memristor has been proposed as the fourth missing fundamental circuit element in 1971. This new circuit element has a charge controlled resistance, saturation mechanism and zero-crossing hysteresis loop which cannot be mimicked by previously known circuit elements. It is a promising candidate for both digital and analog electric circuit applications. In this work, a memristor based timer circuit is proposed. Concept of the circuit is presented and its analysis is done. Simulation of the timer is done using the linear drift model of the TiO2 memristor and the result is compared to the analytical calculations.

An ultra low-voltage ultra low-power memristor

Memristor can provide new approaches especially in nonlinear & chaotic circuit design. Since no commercially available memristor exist until yet, obtaining of a practical implementation which behaves as a memristor, is very important from the point of view real-world circuit design. In this work, an ultra low-voltage ultra low-power DTMOS-based design of memristor is presented. A new ultra low-voltage, ultra low-power operational amplifier and a new ultra low-voltage, ultra low-power multiplier are also proposed to use in the realization. Our design is composed of these two type active blocks using CMOS 0.18μm process technology with symmetric ±0.25V supply voltages. Characteristics and performance of our design is verified by PSPICE simulations. Total power consumption of the proposed memristor is found as just 4.3μW which is suitable for ultra low-power consumption. The simulation results show that our design provides the characteristics of memristor accurately and it could be a viable and convenient option especially in low-voltage low-power memristor based chaotic applications.

Frequency and time domain characteristics of memristor-based filters

Memristor, regarded as the new fourth fundamental circuit element by many, is also being considered for analog applications. It is expected that analog filters with memristors will provide some characteristics which cannot be mimicked by resistors. In this study, memristor-based low-pass and high-pass filters are analyzed and their performance demonstrated with simulations in time and frequency domains. Saturation of the memristor in the memristor-based filters at low frequencies and distortion resulting from it are observed. Also gain and total harmonic distortion of the filters as a function of frequency are given. The results obtained in this work can be used to design, memristor-based low-pass and highpass filters.

Small signal model of memcapacitor-inductor oscillation circuit

To extend the concept of the memristive systems to capacitive systems, memcapacitive systems have been described in 2009. Memcapacitors which are a subset of memcapacitive systems are flux-dependent nonlinear circuit elements with memory. Materials with memcapacitive properties has already been reported in literature. The elusive memcapacitor show promise for new type of applications because of their unusual characteristics which cannot be mimicked with linear circuit elements. Since these elements are not commercially available yet, their analytical solutions and simulation studies are very important. Then these solutions may provide valuable insight for their usage, behavior and predicting of their new application areas. In this study, a memcapacitor-inductor oscillation circuit is examined using simulations and also its small signal equivalent circuit is obtained using perturbation theory since such a circuit does not have an exact solution.

Measurement of electromagnetic radiation around wind turbines

The number of wind energy plants in energy production is rapidly increasing in many countries of the world. In recent years, as an alternative energy source, it has been observed that wind energy installations have been established in various regions of our country. Wind turbines are sometimes discussed with the concern that the electromagnetic fields around them can cause health problems. In this study, ELF electromagnetic field levels are given, obtained around the 16.2 km long transmission line which enables the energy generated in 50 wind energy energy central turbines operating in Izmir-Karaburun locality to be transported to the 380kV Karaburun Havza GIS TM transformer center. The results are obtained in magnetic field and electric field. And they are evaluated for electromagnetic pollution in terms of environment and human health.

Electromagnetic radiation interaction and pollution measurements

Electromagnetic waves caused from base stations, which are rapidly increasing due to the opportunities provided by modern technology, create an undesired effective electromagnetic pollution in the environment. Mobile phones, as an important electromagnetic radiation source in the human body, are deliberately preferred devices for their use. However, those who live near base stations are exposed to electromagnetic radiation outside of personal preference and often are unaware of this effect. Especially, in districts with high populations such as Kadıköy, possible negative effects should be systematically examined by independent measurement institutions. In this study, the results of the 3-year project entitled “Determination of Electromagnetic Radiation from Base Stations at Istanbul Kadıköy and Determination of Exposure Levels” are discussed in comparison with national and international limits.