Abdullah Eroglu

The Complete Design of Microstrip Directional Couplers Using the Synthesis Technique

A symmetrical microstrip directional coupler design using the synthesis technique without prior knowledge of the physical geometry of the directional coupler is analytically given. The introduced design method requires only the information of the port impedances, the coupling level, and the operational frequency. The analytical results are first validated by using a planar electromagnetic simulation tool and then experimentally verified. The error between the experimental and analytical results is found to be within 3% for the worst case. The design charts that give all the physical dimensions, including the length of the directional coupler versus frequency and different coupling levels, are given for alumina, Teflon, RO4003, FR4, and RF-60, which are widely used in microwave applications. The complete design of symmetrical two-line microstrip directional couplers can be obtained for the first time using our results in this paper.

Applied Cyber-Physical Systems

Applied Cyber-Physical Systems presents the latest methods and technologies in the area of cyber-physical systems including medical and biological applications. Cyber-physical systems (CPS) integrate computing and communication capabilities by monitoring, and controlling the physical systems via embedded hardware and computers. This book brings together unique contributions from renowned experts on cyber-physical systems research and education with applications. It also addresses the major challenges in CPS, and then provides a resolution with various diverse applications as examples. Advanced-level students and researchers focused on computer science, engineering and biomedicine will find this to be a useful secondary text book or reference, as will professionals working in this field.

PLANAR INDUCTOR DESIGN FOR HIGH POWER APPLICATIONS

Design, simulation, and implementation of low proflle microstrip spiral inductors for high power Industrial, Scientiflc and Medical (ISM) applications at the high frequency (HF-3{30MHz) range are given for the flrst time. An accurate analytical model and algorithm have been developed to determine the simplifled lumped element equivalent model parameters for spiral inductor and its physical dimensions. Five difierent spiral inductors are then simulated with a planar electromagnetic simulator using the physical dimensions obtained for the desired inductance values with the analytical method. The implementation method and substrate selection for spiral inductors at the HF range are given in detail for high power applications. The spiral inductors are then constructed on 100mil Alumina substrate and measured with network analyzer. It is found that analytical, simulation and measurement results are in close agreement and the analytical method and algorithm that have been developed can be used to accurately determine the physical dimensions, and the resonant frequency of the spiral inductor for the desired inductance value.

Non-Invasive Quadrature Modulator Balancing Method to Optimize Image Band Rejection

The design, simulation, and implementation of a non-ideal quadrature modulator balancing system based on the image rejection using correction factors with non-invasive and simple method is given. The novel balancing system proposed in this paper improves the performance of the quadrature modulator by eliminating the imperfections inherent in the RF systems. Furthermore, the proposed system improves DC offsets that can exist at the output of digital-to-analog converters in addition to frequency-dependent loss and phase shift of low-pass anti-aliasing filters by optimizing the image band rejection. The complete analytical model for a non-ideal quadrature modulator is developed and verified for several conditions. The method is non-invasive and requires only two sets of measurements to obtain the correction factors for amplitude and phase of I and Q signals. The proposed method eliminates the requirement for existing time consuming pre-calibration methods where the system is measured before operation and correction factors that depend on several parameters are stored in memory to be recalled during operation.

Complete Modeling of Toroidal Inductors for High Power RF Applications

High frequency toroidal model is developed and used to calculate several critical inductor parameters such as inductance, resonance frequency, quality factor, power loss, flux density with good accuracy for high power RF applications. The model that is developed is then transformed to the equivalent circuit, which is used by impedance analyzers to compare measurement and calculate results for several parameters. Full design and characterization program Matlab GUI has been generated to calculate and present high frequency characteristics of the toroidal inductor graphically. Program gives all the required design critical parameters, 15 output characteristic curves with high accuracy. The program can be used for commercial and academic applications. The accuracy of the program has been tested on several assembled inductors. The calculated results have been compared to the measured results and good agreement has been observed on all of them.

Phase controlled Class E amplifiers for pulsing applications

The complete design of phase controlled Class E amplifiers for pulsing applications is given. Class E amplifier operating at high frequency (HF) range is designed, simulated, implemented and tested using the introduced method. Amplifier is pulsed up to 100 kHz at the rated power with duty cycles ranging from 10 percent to 90 percent. Experimental results are found to be very close to the simulation results. It is shown that pulsing through phasing enabled fast switching with wide range of duty cycles. The method described in this paper can be used in the design of switch-mode power amplifiers for applications including semiconductor wafer processing, medical resonance imaging (MRI), radar, telecommunication, and laser.

Novel broadband multilayer microstrip directional couplers

Design method of novel multilayer, broadband six port microstrip directional coupler at VHF- UHF range for high power applications is given. Directional coupler is modeled and simulated with the method of moments based planar electromagnetic simulator on a two-layer Alumina substrate. It is shown that the high directivity and desired coupling level of the directional coupler are maintained within 300MHz of bandwidth using the proposed design method in this paper. Results of this work can be used in the design of broadband directional couplers for high power RF/Microwave applications.

Wave propagation and fresnel coefficients for three layered uniaxially anisotropic media with arbitrarily oriented optic axes

Fresnel coe-cients for three-layered uniaxially anisotropic media with arbitrarily oriented optic axes have been obtained using half-space re∞ection and transmission coe-cients. The optic axes of the anisotropic media are assumed to be tilted at difierent angles ((ˆi, ´i), i = 1; 2). This gives arbitrary orientation for anisotropic medium in the stratifled conflguration. The half space coe-cients are derived at the boundary surfaces of two difierent media including isotropic- anisotropic, anisotropic-anisotropic, anisotropic-isotropic interfaces with the application of boundary conditions. The interface between two media for the three-layered media leads to four difierent cases of wave propagation, which are analyzed in detail. The results are compared with the existing results in the limiting cases analytically. The results presented in this paper can be used to establish dyadic Greens functions, which can be used to calculate radiation and scattering from the stratifled structure.

Dual directional coupler design with transformers

The complete analytical model for dual or six port directional coupler is developed, and closed form equations using operational parameters are presented for the first time using transformers. Six-port coupler using the model developed is designed and simulated with frequency domain simulator Ansoft Designer for verification. Final design is implemented and measured with network analyzer. Analytical, simulation and measurement results are compared and agreement has been values. Matlab GUI to design six-port directional couplers has been developed for academic and commercial use with implementation of the analytical model developed in this paper.

The complete model of high efficient drive system for electric vehicles

The complete design, simulation and implementation of high efficient drive system for electric vehicles (EVs) is presented. The drive system consists of brushless DC Motor (BLDC), novel bi-directional dc-dc converter, Lithium ion (Li-ion) battery pack, charger, solar panel and control system. The complete electric vehicle drive system is modeled and simulated using MATLAB/ Simulink with manufacturer data. The prototype for the drive system then has been built and measured. Agreement has been observed between the analytical, simulated and experimental results.