Engineering Commons^™

Relationship Between Time-Constants And 3db Cutoff Of High-Order Damped Lti Systems, Vladimir I. Prodanov, Katherina Prodanov

Electrical Engineering

This paper deals with linear time-invariant (LTI) systems and examines the link between the 3dB cutoff and time-constants. It shows that the cutoff frequency of a low-pass damped network can be estimated from the reciprocal of a p-norm calculated from the system's time-constants. Furthermore, to achieve good accuracy the p factor must have a fractional value, for example, p=1.7. Two formulas are derived, and their performance evaluated using Monte Carlo simulations which reveal a sub-3% error for most cases.

Experimental Study And Modeling Of The GM-I Dependence Of Long-Channel Mosfets, Michael Cheng, Vladimir I. Prodanov

Electrical Engineering

This paper describes an experimental study and modeling of the current-transconductance dependence of the ALD1106 and ALD1107 arrays. The study tests the hypothesis that the I-g _m dependence of these 7.8 μm MOSFETs conforms to the Advanced Compact Model (ACM). Results from performed measurements, however, do not support this expectation. Despite the relatively large length, both ALD1106 and ALD1107 show sufficiently pronounced `short-channel' effects to render the ACM inadequate. As a byproduct of this effort, we confirmed the modified ACM equation. With an m factor of approximately 0.6, it captures the I-g _m dependence quite well. The paper also introduces …

Alumni Grassroots Leadership Enables Sponsored Course Development, Vladimir I. Prodanov, John Greene

Electrical Engineering

This paper presents a lab-centric course development where alumni, employed by an IAB member company, play a pivotal role. Recently the lead author of this paper qualified for a sabbatical leave and the college enthusiastically approved the proposal (a 400-level elective in networked sensors). He considered two class structures: lecture-only and lecture-lab. While lecture-lab is the desired mode of instruction, the development of such a course would take at least 2 quarters. Since extended sabbaticals are only partly funded by the university the creation of a lecture-lab course hinged on the availability of a sponsor. Simultaneously an alumnus, now with …

Method For Selecting Coupling And By-Pass Capacitors In Multi-Stage Linear Circuits, Vladimir I. Prodanov, Dale Dolan

Electrical Engineering

A method for selecting a set of coupling and by-pass capacitors is presented. The approach uses short-circuit time-constant analysis and for a given −3 dB cut-off frequency minimises the total capacitance used. This study offers a derivation of design formulas and shows their use via examples.

Uhf Rfid Antenna Impedance Matching Techniques, Kamron Sockolov, Dean Arakaki

Electrical Engineering

The modified T-match network uses planar inductive strips for conjugate matching Radio Frequency Identification (RFID) Integrated Circuits (RFICs). Narrow and broadband matching techniques and electromagnetic simulations are applied in [1] for specific designs. This paper extends these efforts through antenna element parameterization and design trade-off analysis. Narrow and broadband designs are fabricated; antenna input impedance and tag range tests confirm predictions.

Lecture Videos To Supplement Electromagnetic Classes At Cal Poly San Luis Obispo, Dean Y. Arakaki

Electrical Engineering

Electromagnetics and Transmission Lines is a fundamental, yet difficult subject in the Electrical Engineering (EE) field. To help improve information retention, a series of lecture videos was created to supplement traditional lectures, to facilitate in-class discussions, and to improve students’ proficiency and interest in electromagnetics.

Engineering electromagnetics classes at California Polytechnic State University, San Luis Obispo cover fundamentals to understand and analyze cell phone communications, radar systems (air traffic control, law enforcement), and biomedical imaging (MRI). However, this subject also requires considerable mathematics preparation in vector calculus, differential equations, linear algebra, and background in both physics and EE.

Lecture videos …

Instructables.Com As A Tool To Improve Student Outcomes And Promote Community Engagement (Work-In-Progress), Andrew Danowitz

Electrical Engineering

Project-based Learning (PBL) has become a popular pedagogical tool in Engineering. Projects force students to put theory learned in lecture into practice, exposes students to some of the nonidealities of real systems (imperfect instruments, uncooperative systems, etc.) that are difficult to convey in lecture or homework, and ideally motivates students by showing how course material is related real-world engineering problems. This work discusses my preliminary and ongoing research into using Instructables.com—a user-content generated website of “Do It Yourself” tutorials—as a tool to help amplify the benefits students derive from PBL. Specifically, I require students to document their projects in an …

A Paramedic Method Drill Master To Improve Student Writing, David Braun

Electrical Engineering

Engineering instructors have students write reports in order to help learn difficult concepts, data analysis, challenging problem solving, communication skills, and critical thinking. Sadly, many students seem to prefer obfuscating the subject matter and key ideas by using painfully unclear writing. An instructor dismayed by poor prose in submitted assignments has numerous familiar options available. Consider just a few:

1. Ignore the poor writing

2. Mark every error directly

3. Mark every error with a marginal comment

4. Give general feedback about the poor writing over the entire assignment

5. Expect students to rewrite and resubmit work

6. Change careers …

Organic-Based Microwave Frequency Absorbers Using Corn Stover, Ben Smythe, Sean Casserly, Dean Arakaki

Electrical Engineering

Commercial antenna test chambers (anechoic) currently use polyurethane foam absorbers on chamber interiors to eliminate undesired radio-frequency (RF) reflections. While effectively absorbing microwave signals, polyurethane material particulates over time adding contaminants to clean rooms and reducing absorber lifetime. These absorbers also release toxic gas when operating under high temperatures and pose a health risk to direct-contact personnel. This paper presents reflectivity analysis and performance of alternative organic-based (corn stover) microwave frequency absorbers for use in anechoic chambers. These absorbers are composed of renewable materials and eliminate the toxic gas release problem for polyurethane materials under high power test conditions. Preliminary …

Multi-Technique Broadband Microstrip Patch Antenna Design, Daniel Colles, Dean Arakaki

Electrical Engineering

Microstrip patch antennas offer low profile and small footprint advantages, but limited operating bandwidth. Substantial research focuses on broadband techniques. This paper presents the design, simulation, fabrication, and characterization of a 30% bandwidth microstrip patch antenna that incorporates multiple broadband techniques while minimizing footprint area. Methods include patch shape, dielectric thickness, and coupling slot optimization, with capacitively-coupled L-probe feeds. The final design incorporates an electrically thick dielectric and circular-E patch geometry. Microstrip L-probe feed and coupling slot dimensions were optimized via HFSS simulations. The final design was fabricated, and then tested in an anechoic chamber. The new design has measured …

A Class-C Amplifier Linearized By A Constant Conduction Angle Biasing Circuit, Gursewak Singh Rai, Vladimir I. Prodanov, Stephen Garber

Electrical Engineering

This work presents a dynamic biasing topology capable of linearizing a Class-C power amplifier (PA). The topology utilizes a control loop that senses the operating conditions of the power device by means of a scaled replica. The loop operates on the principle of keeping the conduction angle constant and thereby ensuring linearity. The work details some of the design considerations that should prove useful to a designer wanting to implement the topology in an RF integrated circuit. Measurement results from a fully-functional low-frequency prototype bring merit to the topology.

Identifying At-Risk Students: How Use Of Optional Study Materials And Collection Of Graded Work Correlate With Academic Performance, Vladimir I. Prodanov

Electrical Engineering

We report on a study designed to identify students at risk by monitoring certain academic behaviors. Two different approaches were implemented. The first one involves monitoring student access of optional homework problems. While this approach was successful in the early identification of students at-risk, optional homework (as opposed to mandatory one) degrades attainment of learning objectives. The second approach relies upon “counting” of uncollected work. Since no grades were posted, the only way for the students to keep track of their performance was to collect their work. Failure to collect graded work, we argue, is indicative of weak motivation, poor …

Methanol Fuel Safety - A Practical Guide, Art Maccarley

Electrical Engineering

This guide was written initially for the students at Cal Poly engaged in the conversion of IC engines to methanol fuel, especially my students working on methanol projects in my course “Automotive Technologies for a Sustainable Future”. It may be of interest to anyone considering the conversion or operation of an engine on methanol, or to those that handle methanol for other purposes. One of many Materials Safety Data Sheets (MSDS) for methanol that can be found online is: http://www.midi-inc.com/pdf/MSDS_Methanol.pdf.

Empirical Model For The Transconductance-Current Dependence Of Short-Channel Mosfets, Vladimir I. Prodanov

Electrical Engineering

This work is concerned with the g_m-I dependence of sub-micrometer MOSFETs. The transconductance-current expression given by the Advanced Compact Model (ACM) is reviewed and simple modification is proposed. The modification yields an expression which (with proper parametrization) captures the g_m-I dependence of short-channel MOSFETs. The proposed expression is “universal” in the sense that it is capable of modeling the g_m-I dependence of long-channel MOSFETs, short-channel MOSFETs, and resistively-degenerated BJTs.

Structural Damage Detection Using Artificial Neural Networks And Wavelet Transform, Arthur Shi, Xiao-Hua Yu

Electrical Engineering

With the ever-increasing demand for the safety and functionality of civil infrastructures, structure health monitoring (SHM) has now become more and more important.

Recent developments in computational intelligence and digital signal processing offer great potentials to develop a more efficient, reliable, and robust structure damage identification system. In this paper, the application of artificial neural networks and wavelet analysis is investigated to develop an intelligent and adaptive structural damage detection system. The proposed approach is tested on an IASC (International Association for Structural Control)-ASCE (American Society of Civil Engineers) SHM benchmark problem. Satisfactory computer simulation results are obtained.

Traffic Signal Optimization Using Ant Colony Algorithm, David Renfrew, Xiao-Hua Yu

Electrical Engineering

Traffic signal control is an effective way to improve the efficiency of traffic networks and reduce users’ delays. Ant Colony Optimization (ACO) is a meta-heuristic algorithm based on the behavior of ant colonies searching for food. ACO has successfully been employed to solve many complicated combinatorial optimization problems and its stochastic and decentralized nature fits well with traffic networks. This research investigates the application of the ant colony algorithm to minimize user delay at traffic intersections. Various ACO algorithms are discussed and a rolling horizon approach is also employed to achieve real-time adaptive control. Computer simulation results show that this …

In-Class Lecture Recording: What Lecture Capture Has To Offer To The Instructor, Vladimir I. Prodanov

Electrical Engineering

The purpose of this study is to determine the impact of lecture recording upon the instructional faculty. The following aspects are explored: 1) impact on class enrollment; 2) impact on class attendance; 3) usefulness of obtained statistical results for course improvement. The study is based upon data collected in a junior-level Electrical Engineering class with enrollment of 76 students. The data was collected using anonymous surveys and Blackboard’s statistical tracking utility. The results from the survey show that providing lecture recordings does not have significant impact upon students’ decision to attend lectures, but it has pronounced impact upon their enrollment …

Student Perception Of Lecture Video Use As A Means To Increase Time For In Class Problem Solving Applications, Dale Dolan, Vladimir I. Prodanov, Taufik

Electrical Engineering

The purpose of this study is to examine student perceptions of lecture video use as a means to increase available time for in class problem solving in a teaching and learning context. A portion of face to face lectures was replaced with prerecorded lecture video whose viewing was assigned for homework. The freed lecture period was used for additional in class problem solving development, without sacrificing the theory and background that is fundamental. In order to assess the effectiveness of the change in format, student perception was assessed through an anonymous online survey. The survey was given at the completion …

Design And Assembly Of An Antenna Demonstration System, Alexander J. Hempy, Michael P. Civerolo, Dean Y. Arakaki

Electrical Engineering

This paper describes the design, assembly, and operation of a self-contained wireless demonstration system that required only dc power supplies. The system demonstrated polarization effects, radiation patterns, gain, directivity, and signal interference from environmental barriers from dipole, corner reflector (simulated antenna array), Quagi, and embedded patch antennas. The system included an RF oscillator, high-frequency amplifiers,RF bandpass filters, a signal-strength indicator, and multiple adjustable antenna-mounting platforms.

Wavelength Dependence Of Transverse Mode Coupling With/Without E-Block Of Gan Laser Cavity, K. Lal, G. Chavoor, Xiaomin Jin

Electrical Engineering

Transverse mode wavelength dependence in the gallium nitride (GaN) laser cavity is a new topic. Modal analysis simulations are run to optimize the blue GaN-based laser diode with a wavelength of 400, 430, and 460 nm. It is shown that the optical confinement factor (OCF) has a strong dependence on wavelength of emission and electron-block (e-block) thickness. The OCF can be changed from 4.9% at a 460-nm wavelength to 7.6% at 400 nm, which is a 55% difference. The effect of adding an e-block layer of different widths is also investigated with results showing that an e-block layer can change …

Electric Vehicle Safety, Art Maccarley

Electrical Engineering

No abstract provided.

A Parallel Energy-Sharing Control For Fuel Cell-Battery- Ultracapacitor Hybrid Vehicle, Jennhwa Wong, N.R. N. Idris, Makbul Anwari, Taufik Taufik

Electrical Engineering

This paper proposes a parallel energy-sharing control for fuel cell hybrid vehicles (FCHVs) application. The hybrid source consists of fuel cells (FCs) stack, battery packs and Ultracapacitor (UC) modules. In the proposed parallel energy sharing control, each source is connected to a DC bus via power electronics converters. A total of six control loops are applied in the supervisory system in order to regulate the DC bus voltage, control of power flow and at the same time to monitor the state of charge (SOC) of each energy storage device. Simulation with experiment verifications are carried out to verify the proposed …

Light Extraction Improvement Of Gan Leds Using Nano-Scale Top Transmission Gratings, Greg Chavoor, Xiaomin Jin, Ashton Ellaboudy, Xing-Xing Fu, Xiang-Ning Kang, Bei Zhang, Guo-Yi Zhang

Electrical Engineering

In this paper, we use a Finite-Difference Time-Domain GaN LED model to study constant wave (CW) average power of extracted light. The structure simulated comprises of a 200nm-thick p-GaN substrate, 50nm-thick MQW, 400nm-thick n-GaN substrate, and a 200nm n-GaN two-dimensional Photonic Crystal(2PhC) grating. We focus on optimizing three design parameters: grating period (A), grating height (d), and fill factor (FF). In the primary set of simulations, we fix the fill factor at 50% and simulate ten different grating periods (100 to 1000nm in steps of 100nm) and four different grating heights (50 to 200nm in steps of 50nm), and calculate …

Improvement Of Solar Cell Efficiency Using Nano-Scale Top And Bottom Grating, Xiaomin Jin, Ashton Ellaboudy, Greg Chavoor

Electrical Engineering

We study solar-cell designs using nano-grating on both top (transmission) and bottom (reflection) of the solar cell. First, we perform simulations based on rigorous coupled wave analysis (RCWA) to evaluate the diffraction top gratins. In RCWA method, we calculate up to 20 harmonics, and sweep the launch angle of incident light from 0 to 90 degree. The incident light varies from100nm to 1200nm wavelength. Triangular grating can achieve higher light absorption compared to the rectangular grating. The best top grating is around 200nm grating period, 100nm grating height, and 50% filling factor, which responses to 37% improvement for triangular grating …

A New Undergraduate Laboratory Course In Magnetic Design, Taufik Taufik, Scott Mcclusky, Jonathon Paolucci, Dale S. Dolan

Electrical Engineering

This paper presents a set of new laboratory experiments developed in conjunction with an undergraduate course in magnetic design. The course has recently been reintroduced as a technical elective course where students learn the basics of inductor and transformer design. Five new laboratory experiments have been developed to cover magnetic concepts and to provide students with the hands-on experience in designing and building magnetic components. The paper presents an overview of the course, and highlights the new lab experiments in the course.

Development Of Wind Tunnel For Laboratory Wind Turbine Testing, Dale S. Dolan, Danny Zepeda, Taufik Taufik

Electrical Engineering

This paper presents the development of a wind tunnel that will be used for wind turbine testing in a controlled environment. The prototype is designed to be able to provide wind speeds of up to 20 m/s (~43mph) depending on the cross sectional area of the tunnel chamber. A 42 inch tube axial fan is driven by a 5hp induction motor using a variable frequency drive to allow continuously variable wind speeds from near zero up to the maximum wind speed. The fan is rated to produce ~25,000 CFM and the corresponding wind speed is therefore dependent on chamber cross …

Lip Localization Algorithm Using Gabor Filters, Robert E. Hursig, Jane Xiaozheng Zhang, Chiweng Kam

Electrical Engineering

This paper describes a lip localization algorithm within a still image frame for subsequent tracking and audiovisual speech recognition processing. A Gabor filter-based feature space is promoted as a means to localize lips within an image based off of shape. This filtered space is shown to effectively differentiate facial features, including lips, from their backgrounds and to bound the full extent of the lips within a face-classified region of interest. Extensive training and test sets are used to justify design decisions and performance.

Aperture Coupled Patch Antenna Design Methods, Michael Civerolo, Dean Arakaki

Electrical Engineering

Microstrip patch antennas have been used extensively in applications requiring low-profile, mounting structure conforming, and low-cost wireless communications. Feed methods (antenna-transmission line interface) are critical for optimum performance. The aperture coupled technique exhibits reduced transmission line radiation and enhanced antenna radiation and co- to cross-pol performance relative to microstrip and probe fed configurations. Researchers have focused on analytical methods and design improvements without identifying parametric tradeoffs or design methods. Hence, this paper presents theoretically and parametrically identified critical antenna dimensions and performance effects, and a design procedure to convert desired performance requirements into operational prototypes.

Teaching Sustainability Analysis In Electronics Lecture Courses, David Braun

Electrical Engineering

Based on positive prior experiences teaching sustainability analysis in electronics laboratory courses, this work explores techniques for teaching sustainability analysis in lecture courses. As difficult as it may seem to incorporate sustainability into integrated circuit courses or other engineering courses, it may prove as easy as asking students to consider how the coursework relates to sustainability issues.

The need to educate students “to design a system, component, or process to meet desired needs within realistic constraints such as economic, environmental, social, political, ethical, health and safety, manufacturability, and sustainability” has gained sufficient value to deserve its own ABET Program Outcome, …

Modeling Of A Gyro-Stabilized Helicopter Camera System Using Artificial Neural Networks, Nicholas Layshot, Xiao-Hua Yu

Electrical Engineering

On-board gimbal systems for camera stabilization in helicopters are typically based on linear models. Such models, however, are inaccurate due to system nonlinearities and complexities. As an alternative approach, artificial neural networks can provide a more accurate model of the gimbal system based on their non-linear mapping and generalization capabilities. This paper investigates the applications of artificial neural networks to model the inertial characteristics (on the azimuth axis) of the inner gimbal in a gyro-stabilized multi-gimbal system. The neural network is trained with time-domain data obtained from gyro rate sensors of an actual camera system. The network performance is evaluated …