Letters / Recommendation Letter for Electrical Engineering Phd Program [3]

reference letter

Dear Admissions Committee,

I am writing this letter to strongly recommend Phyllis Wang for the position of PhD in your department. She completed her M.S. in my lab from 2013 to 2015 and ranked among my best students. I recommend her to you highly.

Ms. Wang was a member of millimeter wave group in my lab. Her main work was the design of oscillator and PLL. She demonstrated the ability to work independently with great intelligence and enthusiasm. She also put in many long hours. She continued to read papers and books about PLL and did a lot of simulations and analyses. We had group meeting every week, and she always made progress and generated interesting hypotheses on the implementation of PLL. She redesigned a 40 GHz PLL which was used in transceivers implemented by my PhD students. That work was published in several high quality papers including JSSC, on which Phyllis is a coauthor. She has a solid understanding of PLL system and PLL circuits design.

Furthermore, she independently designed an 80 GHz DCO based on DiCAD technique and implemented it in 65nm CMOS. This work shows not only her ability to quickly master different kinds of simulation software and to understand the principle of simulation results but also her sophisticated operation skill of testing instruments. This work was published in SCI journal, which attests to her hard work and outstanding writing skill. Ms. Wang proved herself an excellent researcher.

I was especially taken by Ms. Wang's high self-motivation and enthusiasm in her major. She did a good job in my graduate class - RF CMOS Integrated Circuits design. To further strengthen her basic knowledge on integrated circuits, she audited my undergraduate class: Analysis and Design of Analog Integrated Circuits.When she had questions she always approached me or other students in my lab to solve those problems. She is an enterprising student who pursues with vigor to understand each topic and has shown perseverance to tackle problems.

In short, I give Phyllis Wang my highest recommendation. She is one of my best students. She did an outstanding job in her position and was an asset to my lab. With superb academic background and dedication for research work, I am confidence that she will excel in her future PhD studies.

If I can be of any further assistance, or provide you with any further information, please do not hesitate to contact me.

Best Regards,

Graduate / Analog/RF IC is an art which has high design flexibility - SOP for PHD in analog IC in USA [3]

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Statement of Purpose

I love analog/Radio-Frequency(RF) Integrated Circuits(IC) because it calls for understanding of multiple disciplines. It urges me to learn as much as possible and to address problems from perspectives of different fields. Besides, analog/RF IC is an art which has high design flexibility. One can never reach a perfect product because of many design trade-offs. What I yearn for is to enrich my knowledge and to design the initiative circuits to challenge the limits. Finally, our daily life is permeated with IC products. Studying this sphere that is closely geared to people's life makes me highly excited and motivated.

I have finished my master's education in A University, one of the top two universities in my country. In my fist year(2012-2013), I took several important courses like Analog Large Scale Integration, The Design of CMOS RF IC and IC Design and Practice, which gave me basic knowledge of circuits analysis and design and made me familiar with the whole analog IC design process.

I had been under Professor Taohong Shi's supervisor for two and a half years. I chose Phase Lock Loop(PLL) as my research since it is widely used and requires knowledge of mixed-circuits design, system design, and RF circuits design. I implemented an 80 - 83 GHz digitally-controlled oscillator in 65nm CMOS. At such a high frequency, I combined Electronic Design Automation(EDA) tools like Cadence, Caliber, High Frequency Structure Simulator(HFSS) and Advanced Design System(ADS) together to carry out the oscillator. The most challenging thing was to design and get the simulation property of floating metal strip slow-wave structure underneath the transmission line and inductance used to realize frequency tuning in LC oscillator. HFSS was used to solve the problem. After a half year's studying tutorial manual, searching discussion about HFSS design examples on EDA forums, consulting seniors for simulation setting advice and reviewing Maxwell field equations, I became confidence in the EM simulating results and gained in-depth understanding and experiences. This work is published in Science Citation Index(SCI) journal, whose impact factor is around one point six.

In addition, I had redesigned a 40 GHz integer-N PLL. To get a deeper understanding of PLL, I sit in Professor Boogeun Chee's class - PLL Design and Clock/Frequency Generation. I applied what I learnt in class to project and got a lot from my project. I became sophisticated in the use of EDA tools. I came to know the importance to study the advanced semiconductor process document. For example, knowing parasitic parameters in the document such as sheet resistance and parasitic capacity on different materials helps a lot in the process of trade-offs between resistance and capacity. Besides, It is important to comprehend the principles of EDA simulators - ADS, HFSS and Spectre - in order to improve accuracy and efficiency by Choosing the appropriate simulation method according to the target circuits. For instance, S-parameter simulator first gets the Direct-Current(DC) operation points by solving circuits with Kirchhoff equations and then linearizes the circuits at the DC point. With that in mind, I will never try to inspect circuits' large-signal model by S-parameter simulator. By applying my acquired theoretical and conceptual skill, I successfully worked out the PLL and gained deep understanding of PLL design. This work was applied in my seniors' dissertations and papers.

I have been working as a RF engineer since I graduated in 2015. I grow intellectually and emotionally in my work. And this experience confirms what I really want to do is academic research. My work contains designing a board-level Radio Frequency Identification(RFID) transceiver, studying datasheets of different chips, drawing Printed Circuit Board(PCB) and testing. The RFID transceiver has experienced more than ten times iterations. The testing results and analysis of the testing phenomena guide us how to improve in the next iteration. I have been sophisticated in the utilize of testing instruments and accumulated precious testing experience which can not be learned by other approaches. I also have deeper understanding of system design. What's more, I learn the importance of team work. At first, I complained some low-tech work such as redrawing PCB again and again, soldering PCB and compiling tedious documents. But looking back afterwards, I see that only each one in the team makes contribution can the whole project go forward smoothly. I still remember that the RFID reader went wrong before certification on a Friday night. All people on the team including software, hardware and structural engineers worked twenty hours nonstop to solve the problem. The best result always comes from a solidly aligned team.

However, I am not satisfied with my work in that it is based on board-level circuits. I am eager to know what the structure is inside the chips and I am thirsty to design my own chips. I am highly interested in transceiver, PLL and other analog/RF IC. My true career interests are IC research. Based on my background and enthusiasm in IC design, I confirmedly believe that I can go much further in my future PHD study. Apart from my work, my personality occupies me to take PHD program smoothly. I am optimistic , adaptable and very tenacious. I once completed half-marathon in two hours and cycled three hundred kilometer in three days.

___ University's Analog/Mixed-signal area and RF/Microwave/Millimeter-wave Circuits and systems area in Integrated Electronics attract me most, largely because of the outstanding faculty and perfect match for my career aspiration. I am particularly interested in Professor ____'s and Professor ____'s lab. They both have strong academic and industry background and their students have published a lot in top research conferences and journals. Together, both of their cutting edge research and deep understanding on Integrated Electronics would make my experience at ____ University a challenging and enjoyable one.