RF test and design
Resume:
Chengzhi Wang
Campbell, CA 95008
********@*******.***
CAREER SUMMARY
• An electrical engineer extensive RF desense experience in cell phone, WiFi/BT and wireless products, including satellite terminals, paging radio stations, microwave trunk transmission systems, integration, manufacturing, design, test and debug, with excellent hands-on experience and ability
• Excellent experience in RF, EMI/EMC debug, analog, digital circuit design and test, test equipment, MFG, GPIB automation test, troubleshooting and debug, prototype, GPS, SoC, power, display, microprocessor, firmware, microwave, ESD, satellite data communication, MAC, VB, C++, LABVIEW, NX, CST, LABWINDOWS, TESTSTAND, MATLAB, Office Suite, Windows, wireless protocol, ADS simulation, 3GPP, LTE, EDGE, TDMA, FDMA, CDMA, GSM, UMTS, HSPA and 1xEVDO
• An excellent quick learner, self-starter, team lead, team player and individual contributor
• A problem solver has good interpersonal skills
PROFESSIONAL EXPERIENCE
Jan 2022 – Present Meta, Sunnyvale
Contractor for RF desense by Global Advantis
• Failure Analysis
• Debug and fix the RX sensitivity de-sense issue to meet the high quality Wi-Fi/BT/LTE requirement of Meta wearable device
• Check the system ground structure and shield using a 3D tool
• Review the layout of the clock, differential pairs, ground and power
• Added decoupling caps
• Test the noise source hot spot by the near field probe
• Run RX sensitivity test
• Coordinate with test equipment vendor to setup test solution
• Narrow down the root cause of de-sense issues by stripping, swapping, isolating, disconnecting, and cut- and-try method
• Instruct DOE online/offline in the factory before design implementation
• Collaborate with multiple teams, including mechanical, antenna, project management team, electrical, analog & digital, software, and RF engineers to negotiate and implement the applicable fix for every rev
• Approve OK2FAB and OK2tool after design review, after working with electrical engineer and PD
• Collect test data from OEM for improving the design of the next rev April 2014 – Nov 2021 Apple Inc., Cupertino, CA
Senior RF de-sense engineer, Direct Responsible Individual for Mac
• Approved OK2FAB and OK2tool after design review, working with electrical engineer and PD
• Traveled to the OEM to instruct the design stage product MFG build before ramp-up
• Collected the test data from the OEM for improving the design of the next rev
• Perform failure Analysis
• Debug and fix the RX sensitivity desense issue to meet the high quality WI-FI/BT requirement of Mac computer
• Check the system ground structure and shield in 3D tool
• Review the layout of the clock, differential pairs, ground, and power
• Added decoupling cap
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• Tested the noise source hot spot by the near field probe
• Ran RX sensitivity test
• Narrowed down the root cause of the de-sense issue by striping, swapping, isolating, disconnecting, cut and try method
• Instruct DOE online/offline in the factory before design implementation.
• Collaborated with multiple cross-functional engineering teams to negotiate and implement the applicable fix for every rev
April 2007 – March 2014 Blackberry Inc., Waterloo, ONT RF Researcher, Team Lead (April 2010 – March 2014)
• Developed non-radio/radio coexistence test method
• Debugged and fixed RX sensitivity desense issues to meet the cell-phone release deadline by dedicated effort
• Checked the system ground metal 3D structure design
• Reviewed the layout of the clock, MIPI, ground and decoupling caps
• Tested the noise source location by the near field probe
• Ran RX sensitivity test
• Narrowed down and fix the root cause of the desense issue by stripping, swapping, isolating and cut-and- try method
• Wrote design and test document
• Generated the test methodology to research the noise spectrum spreading and clock characteristics of non- radio components, such as LCD/ OLED, camera, and power for a better design in early stages, before the POP or ASY is available
• Simulated the S21 from the noise source to the antenna in a CST model
• Collaborated with multiple design teams, including antenna, system, power, memory, processor, software, RF, Wi-Fi/BT, GPS and Carrier spec test team
• Led and coordinated the lessons learned and experienced in exchange meetings for this multi-location R&D company, and gave the meeting minutes
Hardware Design Engineer (April 2008 – April 2010)
• Maintained in-life product design and quality issues o Debugged and tracked the top five failure RMA, worked closely with GRS deep dive, hardware, software and mechanical design groups, generated ECR, TDN, CPR, QRA, yield, HDVT and MIL for the test and design changes
• Handled vendor PCN, and second source qualification test
• Responsible for the technical hardware aspects of one handheld product line from the first stages of design to production and beyond, through to the end of life Hardware System Integration Engineer (April 2007 – April 2008)
• Implemented system hardware into the next generation of cell phone, working closely with the various hardware, software and mechanical groups to optimize performance and integration, and used that information to create schedules and effectively manage prototype builds through product development Dec 2000 – March 2007 Transcore Link Logistics Inc. Test, Product Engineer & Electronics Technologist (Dec 2000 – March 2007)
• Built and tested a prototype of a GPS satellite product, wrote RF and baseband test plan, block and detail design documents, selected and verified test equipment, developed test fixture and test circuit, generated test script, performed worst case analyses and design for temperature effects, performed debug and troubleshooting, did IC testing according to datasheet to fit the design requirement for ECO, collaborated with hardware and software design people in firmware, RF and baseband circuit, and handled RMA test and maintenance
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• Fabricated ATE test station and procedures for MDT, MT 2000, MT 1000, MT3300, MT 3550 GPS satellite data communication terminal
• Programmed and modified test software in C++, VB, LABVIEW, TESTSTAND, LABWINDOWS for RF and baseband circuits
• Frequently traveled to provide technical support to contract manufacturing, trained factory engineers and technicians, gave troubleshooting procedures, troubleshot the manufacturing and test process by collecting and analyzing data, reduced test time cost, searched the database, and generated a yield report Sept 1990 – Aug 2000 Tianjin Wireless Branch of China Telecom Inc. (China Unicom Inc.) Telecommunication Electronics Engineer (June 1994 – Aug 2000)
• Developed the test and debug of RF and microprocessor board in a paging system and GSM cellular phone for customers
• Researched the failure of RF, analog and digital circuits to improve the design and manufacturing with the collaboration of Motorola, NEC, CASIO, PANASONIC And PHILIPS Inc.
• Wrote reports with hands-on debug when failure reason could not be found by other people
• Installed a certificated RMA test center in engineering in collaboration with MOTOROLA Co. Ltd. for large volumes of the product
o The center acted as a lab and the last part of manufacturing assembly line to some extent in order to solve RMA and maintenance without returning product to factory o Installed the troubleshooting procedure, specified and verified new test equipment, realized final RF test, reduced time cost, trained technicians and engineers, wrote maintenance standard for testing instruments and special tools, updated operation standard for new products, serving 300K wireless customers
• Designed the e-Commerce infrastructure of a wireless system, led a group of software and hardware engineer to integrate all these systems together to develop IVR, VoIP system and internet paging website in SCO UNIX, WINDOW NT, C++, Dialogic and ORACLE database with E1 and ISDN in the system o Increased system volume by replacing an old DIGITAL server to SUN server, switched online system from novel to Sun Solaris for the manual paging operator computer network, linked system together with another Sun 550 server in the financial department, and supervised auxiliary instant voice response and fax system in Windows NT
• Directly reported to Chief Director to investigate the failure of paging signal between transmission and pagers
o Introduced a new test method and equipment, compared POCSAG and FLEX wireless paging protocol, introduced GPS time synchronizing to eliminate the interference from different Base Transmission Station with the collaboration of MOTOROLA Co. Ltd., which increased paging rate from 12 to 1200, from 1200bit/s POCSAG protocol to 6400-bits/s MOTOROLA FLEX protocol o Designed the maintenance process and improved the service Sept 1990 – June 1994
• Verified and administered the 150MHz Glenayre paging control system GL3000, installed base transmission station, including antenna, data link and remote control
• Installed, verified and integrated a 1.5GHz digital radio multiple access subscriber system for NEC Inc.
(TDMA) in the field, including mounting the rack, setting the power supply, adjusting the dish antenna on the tower, verifying system performance with test equipment, and administering the system
• Found failures and reacted at once, switched auxiliary backup, traveled to fix failure system in coverage area, and installed, tested and integrated DMR700 11GHz microwave and optical system for NEC Inc. o (FDMA), debugged and troubleshot failure in the system and board, and used supervising software to program BATCH file to improve automation monitoring of system o Investigated BER reason for transmission in a direction to see if it is still within the design range EDUCATION & TRAINING
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• MS, Computer Engineering, Tianjin University, China, 1999
• BS, Electronics Engineering, Tianjin Institute of Technology, China, 1990
• Language for Leadership Training, Blackberry, Canada, 2012
• Language for Effective Communication Training, Blackberry, Canada, 2012
• TESTSTAND training, National instrument, Canada, 2010
• MATLAB training, MathWorks, Canada, 2008
• Agilent RF Measurement, Canada, 2007
• LabVIEW basics I II, National instrument, Canada, 2005
• Advanced Management Course, Engineering After Sales Service, Motorola Inc., 1998
• CASIO Pager Circuit, Manufacturing, Test and Debug. Langchao CASIO Joint Venture Electronic Co. Ltd., 1997
• NEC Pager Circuit, Test, Manufacturing, Integration and Debug, NEC Inc., 1996
• Motorola Pagers Circuit, Manufacturing, Test, Debug and Motorola Microprocessor Design, Motorola Inc., 1995
• Training on Panasonic Pager, circuit, test, manufacturing, debug, Beijing Mitsubishi (Panasonic) Telecommunication Co. Ltd., 1994
• Microwave System Installation, Test and Administration, Beijing Post-Telecommunication University, 1991 TOOLS & SKILLS
Agilent 8960, CMW, LifePoint, Anritsu box, spectrum analyzer, network analyzer, logic analyzer, noise figure meter, frequency counter, RF power meter, oscilloscope, Agilent WLAN test, signal generator, MATLAB, GPIB, LABVIEW, TESTSTAND, 3D tool, CST, LABWINDOWS, ORCAD, Cadence, Zuken schematic capture and layout, Allegro, VISIO, Mac, MS OFFICE, Python programming and Shell Script
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