UNT Libraries - 11 Matching Results

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Parameter Estimation of Microwave Filters

Description: The focus of this thesis is on developing theories and techniques to extract lossy microwave filter parameters from data. In the literature, the Cauchy methods have been used to extract filters’ characteristic polynomials from measured scattering parameters. These methods are described and some examples are constructed to test their performance. The results suggest that the Cauchy method does not work well when the Q factors representing the loss of filters are not even. Based on some prototype filters and the relationship between Q factors and the loss, we conduct preliminary studies on alternative representations of the characteristic polynomials. The parameters in these new models are extracted using the Levenberg–Marquardt algorithm to accurately estimate characteristic polynomials and the loss information.
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Date: December 2015
Creator: Sun, Shuo

An Arduino Based Control System for a Brackish Water Desalination Plant

Description: Water scarcity for agriculture is one of the most important challenges to improve food security worldwide. In this thesis we study the potential to develop a low-cost controller for a small scale brackish desalination plant that consists of proven water treatment technologies, reverse osmosis, cation exchange, and nanofiltration to treat groundwater into two final products: drinking water and irrigation water. The plant is powered by a combination of wind and solar power systems. The low-cost controller uses Arduino Mega, and Arduino DUE, which consist of ATmega2560 and Atmel SAM3X8E ARM Cortex-M3 CPU microcontrollers. These are widely used systems characterized for good performance and low cost. However, Arduino also requires drivers and interfaces to allow the control and monitoring of sensors and actuators. The thesis explains the process, as well as the hardware and software implemented.
Date: August 2015
Creator: Caraballo, Ginna

Design fully-integrated dual-band two-stage class-E CMOS PA

Description: In retrospect we can see that from the last century, wireless electronic technology has been in a rapid state of development. With the popularity of wireless communication, the power amplifier demand is rising. In general, magnitude, maximum noise figure, minimum noise figure, efficiency, and output power are important indicators of the amplifier. The IC industry is exploring how to reduce the additional cost and improve the high-frequency performance. Therefore, designing a strong adaptability and high cost performance of the PA has become a priority. As these technologies advance, the power amplifiers need to have better integration, lower cost, and lower power dissipation. Also, some special requirements are being asked in some areas, such as multi-mode and multi-band. In general, people have to use several power amplifiers parallel to frame a multifunction chip. Each of them working at different frequencies of interest has to have separate matching network, design, and area; also, the diversity amplifier prices will increase with the number of amplifiers, and its cost is also changed. In this thesis, because Class E power amplifier has lower power dissipation, 100% ideal efficiency, simple circuit structure, and strong applicability, the Class E is used as power amplifier in main stage. Moreover, in order to decrease input power and increase output power, the class A power amplifier is used as driver stage. It can use very small amount of power to provide a larger power. Moreover, we use a switched variable inductor and capacitor to constitute a dual band matching network which can let the PA work at more than one frequency. In fact, we design a Class A PA which is as a driver stage. Then, when we support 1 dBm input power, the driver stage can have 8 dBm output power. Also the output will be the input power ...
Date: August 2015
Creator: Zhao, Chao

Design of Frequency Output Pressure Transducer

Description: Piezoelectricity crystal is used in different area in industry, such as downhole oil, gas industry, and ballistics. The piezoelectricity crystals are able to create electric fields due to mechanical deformation called the direct piezoelectric effect, or create mechanical deformation due to the effect of electric field called the indirect piezoelectric effect. In this thesis, piezoelectricity effect is the core part. There are 4 parts in the frequency output pressure transducer: two crystal oscillators, phase-locked loop (PLL), mixer, frequency counter. Crystal oscillator is used to activate the piezoelectricity crystal which is made from quartz. The resonance frequency of the piezoelectricity crystal will be increased with the higher pressure applied. The signal of the resonance frequency will be transmitted to the PLL. The function of the PLL is detect the frequency change in the input signal and makes the output of the PLL has the same frequency and same phase with the input signal. The output of the PLL will be transmitted to a Mixer. The mixer has two inputs and one output. One input signal is from the pressure crystal oscillator and another one is from the reference crystal oscillator. The frequency difference of the two signal will transmitted to the frequency counter from the output of the mixer. Thus, the frequency output pressure transducer with a frequency counter is a portable device which is able to measure the pressure without oscilloscope or computer.
Date: August 2015
Creator: Ma, Jinge

Modeling and Control of a Motor System Using the Lego EV3 Robot

Description: In this thesis, I present my work on the modeling and control of a motor system using the Lego EV3 robot. The overall goal is to apply introductory systems and controls engineering techniques for estimation and design to a real-world system. First I detail the setup of materials used in this research: the hardware used was the Lego EV3 robot; the software used was the Student 2014 version of Simulink; a wireless network was used to communicate between them using a Netgear WNA1100 wifi dongle. Next I explain the approaches used to model the robot’s motor system: from a description of the basic system components, to data collection through experimentation with a proportionally controlled feedback loop, to parameter estimation (through time-domain specification relationships, Matlab’s curve-fitting toolbox, and a formal least-squares parameter estimation), to the discovery of the effects of frictional disturbance and saturation, and finally to the selection and verification of the final model through comparisons of simulated step responses of the estimated models to the actual time response of the motor system. Next I explore three different types of controllers for use within the motor system: a proportional controller, a lead compensator, and a PID controller. I catalogue the design and performance results – both in simulation and on the real system – of each controller. One controller is then selected to be used within two Controls Systems Engineering final course projects, both involving the robot traveling along a predetermined route. The controller’s performance is analyzed to determine whether it improves upon the accumulation of error in the robot’s position when the projects are executed without control.
Date: August 2015
Creator: Mitchell, Ashley C.

A Preliminary Controller Design for Drone Carried Directional Communication System

Description: In this thesis, we conduct a preliminary study on the controller design for directional antenna devices carried by drones. The goal of the control system is to ensure the best alignment between two directional antennas so as to enhance the performance of air-to-air communication between the drones. The control system at the current stage relies on the information received from GPS devices. The control system includes two loops: velocity loop and position loop to suppress wind disturbances and to assure the alignment of two directional antennae. The simulation and animation of directional antennae alignment control for two-randomly moving drones was developed using SIMULINK. To facilitate RSSI-based antenna alignment control to be conducted in the future work, a study on initial scanning techniques is also included at the end of this thesis.
Date: August 2015
Creator: AL-Emrani, Firas

Airbourne WiFi Networks Through Directional Antenna: An Experimental Study

Description: In situations where information infrastructure is destroyed or not available, on-demand information infrastructure is pivotal for the success of rescue missions. In this paper, a drone-carried on demand information infrastructure for long-distance WiFi transmission system is developed. It can be used in the areas including emergency response, public event, and battlefield. The WiFi network can be connected to the Internet to extend WiFi access to areas where WiFi and other Internet infrastructures are not available. In order to establish a local area network to propagate WIFI service, directional antennas and wireless routers are used to create it. Due to unstable working condition on the flying drones, a precise heading turning stage is designed to maintain the two directional antennas facing to each other. Even if external interferences change the heading of the drones, the stages will automatically rotate back to where it should be to offset the bias. Also, to maintain the same flying altitude, a ground controller is designed to measure the height of the drones so that the directional antennas can communicate to each other successfully. To verify the design of the whole system, quite a few field experiments were performed. Experiments results indicates the design is reliable, viable and successful. Especially at disaster areas, it’ll help people a lot.
Date: May 2015
Creator: Gu, Yixin

Design of Multi Band Microwave Devices Using Coupled Line Transmission Lines

Description: Multi band technology helps in getting multiple operating frequencies using a single microwave device. This thesis presents the design of dual and tri band microwave devices using coupled transmission line structures. Chapter 2 presents the design of a novel dual band transmission line structure using coupled lines. In chapter 3, Design of a dual band branch line coupler and a dual band Wilkinson power divider are proposed using the novel dual band transmission line structure presented in the previous chapter. In chapter 4, Design of a tri band transmission line structure by extending the dual band structure is presented. The Conclusion and future work are presented in chapter 5.
Date: May 2015
Creator: Katakam, Sri

Dual-Band Quarter Wavelength and Half Wavelength Microstrip Transmission Line Design

Description: The thesis represents the design for dual-band quarter wavelength and half wavelength microstrip transmission line. Chapter 2 proposed the design of a novel dual-band asymmetric pi-shaped short-circuited quarter wavelength microstrip transmission line working at frequencies 1GHz and 1.55 GHz for 50Ω transmission line and at frequencies 1GHz and 1.43GHz for 60Ω transmission line. Chapter 3 proposed the design of a novel dual-band quarter wavelength microstrip transmission line with asymmetrically allocated open stubs and short-circuited stubs working at frequencies 1GHz and 1.32GHz. Chapter 4 proposed the design of dual-band pi-shaped open stub half wavelength microstrip transmission line working at frequencies 1GHz and 2.07GHz. Numerical simulations are performed both in HyperLynx 3D EM and in circuit simulator ADS for all of the proposed designs to measure the return loss (S11) and insertion loss (S12) in dB and phase response for S12 in degree.
Date: May 2015
Creator: Imran, Md Asheque

Practical Robust MIMO OFDM Communication System for High-Speed Mobile Communication

Description: This thesis presents the design of a communication system (PRCS) which improves on all aspects of the current state of the art 4G communication system Long Term Evolution (LTE) including peak to average power ratio (PAPR), data reliability, spectral efficiency and complexity using the most recent state of the art research in the field combined with novel implementations. This research is relevant and important to the field of electrical and communication engineering because it provides benefits to consumers in the form of more reliable data with higher speeds as well as a reduced burden on hardware original equipment manufacturers (OEMs). The results presented herein show up to a 3 dB reduction in PAPR, less than 10-5 bit errors at 7.5 dB signal to noise ratio (SNR) using 4QAM, up to 3 times increased throughput in the uplink mode and 10 times reduced channel coding complexity.
Date: May 2015
Creator: Grabner, Mitchell John James

Quantitative Correlation Analysis of Motor and Dysphonia Features of Parkinsons Disease

Description: The research reported here deals with the early characterization of Parkinson’s disease (PD), the second most common degenerative disease of the human motor system after Alzheimer’s. PD results from the death of dopaminergic neurons in the substantia nigra region of the brain. Its occurrence is highly correlated with the aging population whose numbers increase with the healthcare benefits of a longer life. Observation of motor control symptoms associated with PD, such as gait and speech analysis, is most often used to evaluate, detect, and diagnose PD. Since speech and some delicate motor functions have provided early detection signs of PD, reliable analysis of these features is a promising objective diagnostic technique for early intervention with any remedial measures. We implement and study here three PD diagnostic methods and their correlation between each other’s results and with the motor functions in subjects diagnosed with and without PD. One initial test documented well in the literature deals with feature analysis of voice during phonation to determine dysphonia measures. Features of the motor function of two fingers were extracted in tests titled “Motor function of alternating finger tapping on a computer keyboard” and “Motor function of the index and thumb finger tapping with an accelerometer”, that we objectively scripted. The voice dysphonia measures were extracted using various software packages like PRAAT, Wavesurfer, and Matlab. In the initial test, several robust feature selection algorithms were used to obtain an optimally selected subset of features. We were able to program distance classifiers, support vector machine (SVM), and hierarchical clustering discrimination approaches for the dichotomous identification of non-PD control subjects and people with Parkinson’s (PWP). Validation tests were implemented to verify the accuracy of the classification processes. We determined the extent of functional agreement between voice and motor functions by correlating test results.
Date: May 2015
Creator: Koduri, Balaram