Engineer Electrical

LIEN H. DANG

**** *** ******* **. ********, TX 77586 281-***-**** (cell)

********@***.***

OBJECTIVE

Engineering position in the areas of research and

development, design and analysis of RF & microwave

components, instruments, and communications/antenna systems.

SUMMARY

. Ph.D. in Electrical Engineering, with concentration in

applied electromagnetics (RF/microwave/antenna), in May

2010, and a M.S. in Electrical Engineering, with

concentration in communications, in June 2000.

. Designed antennas including low profile high-power

reduced lateral disk antennas, microstrip antennas,

arrays and feed networks.

. Modeling and simulations performed using Ansoft

Designer/HFSS, and CST Microwave Studio

. Tested, troubleshot, and debugged RF/microwave

synthesizers and oscillators.

Engineering tools: Ansoft Designer/HFSS, CST Microwave

Studio, MathCad, MatLab, Orcad Capture, P-Spice

Computer Languages: Visual Basic, LabVIEW,

FORTRAN

EXPERIENCE

12/04 - Present University of Houston

Ph.D., Electrical Engineering-Applied Electromagnetics:

RF/microwave

Design Research Project:

Researched, analyzed and designed a low profile high-

power waveguide-fed microwave antenna that has a reduced

level of lateral radiation-radiation that travels along the

supporting ground plane, potentially causing serious

coupling, interference, and diffraction problems.

The behavior of this antenna design was studied using full-

wave simulated results and also using a computer-aided

design (CAD) circuit model developed for the antenna.

Antenna configurations having varied dimensions were

simulated using Ansoft HFSS, a 3D simulation software,

providing results for tradeoff analyses, in which the

relative lateral radiation level, the input impedance, the

impedance bandwidth, as well as the electric field at

critical edges are the determining parameters.

The electric breakdown strength of the antenna was

optimized by minimizing the maximum antenna near-field,

achieved by structurally smoothing out antenna sharp edges.

A pressurized gas was also assumed, which allows the

antenna to handle high power levels.

The reduced lateral wave (RLW) antenna was integrated into

a uniform planar triangular array that is designed to avoid

grating lobes in the E plane, and offers reduced lateral

radiation. The array experiences low mutual coupling thanks

to the reduced levels of lateral radiation in the single

RLW antenna. Matching networks were also proposed for the

array to minimize reflected power.

PUBLICATIONS

L. H. Dang, D. R. Jackson, and J. T. Williams, "High Power

Waveguide-Fed Reduced Lateral Wave Antenna," IEEE AP-S

Intl. Symp. Digest, July 11-17, 2010, Toronto, Ontario,

Canada.

L. H. Dang, D. R. Jackson, and J. T. Williams, "High Power

Waveguide-Fed Reduced Lateral Wave Disk Antenna," IEEE

Trans. Antennas and Propagation, in preparation.

Boeing

Communications and Tracking Engineer

International Space Station Program:

Analyzed and determined compensation parameters for

the Ku band antenna to improve the probability of capturing

the Tracking and Data Relay Satellite. Validated

protective masks for the Ku-band antenna.

Tracked, traced and studied S-band antenna system signals

properties, sources and destinations.

System Safety Engineer

Space Shuttle Orbiter Program:

Developed system safety and reliability requirements;

performed safety analyses: hazards, failure mode and

effects analysis (FMEA), and fault trees; prepared Orbiter

Hazard Reports and FMEA/CILs for the following subsystems:

Guidance, Navigation & Control, Electrical Power

Generation, and Power Reactants Storage and Distribution.

5/02 - 1/04 Accuray, Inc.

Sr. Test/Integration Engineer

Accuray develops and manufactures the CyberKnife stereotactic

radiosurgery system using linear accelerator microwave

technology to produce X-rays providing treatments for solid

cancers throughout the human body by precise deliveries of

high doses of radiation:

Designed analog and digital test hardware simulating

the input signals of the real CyberKnife

system to checkout the CyberKnife subsystems and components:

dose signal counters; command, control, and

monitoring PCBs; power control PCBs; robot command,

control and safety systems.

Designed software test codes in Visual Basic.

Automated diagnostic system for PCBs using a Window-

based PC test station with National Instruments VXI-

1200 FlexFrame and VXI-PCI board. This test station

communicated to the boards under test via VME data bus

interface (VXI-MXI-2), and controlled test fixture

through DIO-128 board-improved troubleshooting time by eight

fold.

Troubleshot system hardware to component level, and

debugged software.

Wrote test procedures, and troubleshooting guides.

Trained and provided technical support to

technicians.

6/01 - 4/02 Anritsu Company

Test Engineer

RF/microwave synthesizers manufacturing group:

Developed test software to scan synthesizers for out-

of-specification spurs, harmonics, and sub

harmonics; maintained and modified Visual Basic test codes.

Troubleshot, debugged test hardware including Window-

based PC test stations which communicated to

test equipment and units under test via IEEE (GPIB) data bus

interface. Equipment used: spectrum analyzer, power

meter, frequency counter.

Performed investigative tests and analyzed data to

isolate failure root causes for production

yield improvement.

6/99 - 5/01 VertiCom, Inc.

Test/Product Engineer

VertiCom designs and manufactures RF/microwave synthesizers

and permanent-magnet YIG oscillators:

Tested, troubleshot, and debugged RF/microwave

synthesizers and oscillators. Equipment used: signal

generator, spectrum analyzer, power meter, frequency counter,

sweeping current supply, scalar network analyzer, and

phase noise analyzer.

Designed, built test hardware fixture for automation.

Automated test/calibration for RF/microwave synthesizer's

phase hits detection boards, and automated

resistance/impedance measurement tests for VIDA oscillators

using LabVIEW, and Window-based PC test stations, which

controlled units under test via DIO interface, and

communicated to test equipment via IEEE (GPIB) data bus

interface- improved operation time by ten fold.

Developed test software in LabVIEW; maintained and

modified Visual Basic test codes for testing of multiple

RF/microwave synthesizers.

Developed test strategies and automated tests for multiple

RF synthesizers-improved test time by four fold.

Trained and provided technical support to technicians and

sub-contractors for the alignment and testing of

RF/microwave synthesizers-parameters of interest: DC and RF

powers, frequency accuracy, harmonics, sub-harmonics, spurs,

phase noise, and phase hits.

Automated oscillator sampler tuning and final test using

LabVIEW and Window-based PC test stations, which

controlled units under test via DIO interface, and

communicated to test equipment via IEEE (GPIB) data bus

interface-this improved test/tuning process by 6 to 1.

Oscillator tuning, and final test were performed manually

using spectrum analyzer, frequency counter, sweeping

current supply, scalar network analyzer, signal

generator, and phase noise analyzer-parameters of interest:

center frequency, output power and power variation, coil

sensitivity, phase noise, hysteresis, second harmonic,

and spurs.

Wrote test procedures (RF/microwave synthesizer alignment,

ATP, amp/multiplier/filter tuning), and troubleshooting

guides (Phase hits, VIDA stabber).

7/95 - 6/99 Boeing / McDonnell Douglas

Sr. Engineer Scientist

International Space Station Program:

Designed test strategies and configurations; developed

test procedures; procured components and equipment (coaxial

couplers, optical and coaxial in-line attenuators, BP & LP

filters, Network Analyzers).

Developed scripts (1553 format, compiled in C) to automate

testing. Proficient with Tektronix 1910, VM700A.

Led technicians, validated signal simulating systems

(optical and coaxial).

Supervised technicians performed video transmission

quality and functional checkouts of RF avionics boxes:

distributing switches, cameras, and optical/electrical

signal converters.

Analyzed system performance. Debugged to component level

to resolve anomalies.

3/87 - 7/95 Rockwell International

System Design Engineer

Orbiter Docking System Program: Created functional flow and

detailed operational sequences; developed design

requirements and specifications involving power control,

instrumentation, communications. Performed system

analyses, trade studies; interfaced with NASA to resolve

design issues.

Awards: Outstanding Teamwork for the Docking CASETS Demo.

Space Shuttle Solar Arrays (IR&D): Researched use

of solar array technology (originated during Rockwell Space

Station proposal) for the Space Shuttle Long Duration

missions.

Test Engineer

Space Shuttle Program: Developed test requirements for the

following Orbiter subsystems: Guidance and Flight Control,

Electrical Power Generation, and Power Reactants Storage and

Distribution. Resolved test issues with NASA, and system

design engineering.

6/86 - 11/86 Grantham College of Engineering

Instructor - Network Analysis, Digital Electronics, Electronic

Devices and Circuits.

Graded exams, homework; prepared lesson material.

EDUCATION & Skills

University of Houston.

Doctor of Philosophy in Electrical Engineering, emphasis in

applied electromagnetics. May 2010. GPA: 3.85

Courses in Major Field:

RF and microwave electronics (amplifier, matching network

analysis and design)

Microwave engineering (microstrip transmission line, filter

analysis and design)

Antenna theory and design Microstrip antenna

Electromagnetics theory Numerical methods for

Electromagnetics

California State University at Fullerton.

Master of Science in Electrical Engineering, emphasis in

communications. June 2000.

GPA: 3.71

Graduate Project: A Time-Hopping Code

Division Multiple Access (CDMA) cellular

telephone system was analyzed and derived.

Parameter of interest: Signal-to-Noise

ratio.

Courses in Major Field:

Spread Spectrum Communication Phase-

Lock Loop & Frequency Feedback Systems

Communication Theory Information Theory & Coding

Random Signals Analysis RF Filters &

Power Amplifiers Design

University of California at Irvine.

Bachelor of Science in Electrical Engineering. March

1986.

Honors: Goodman Scholarship, Irvine Memo

Scholarship.

REFERENCES

US citizen. Secret clearance (DISCO), presently expired.

Contact this candidate