0 EE 448 University of Southern California Department of Electrical Engineering Dr. Edward W. Maby...

Slide # 1

EE 448

University of Southern California

Department of Electrical Engineering

Dr. Edward W. Maby

Class #1 11 January 2005

University of Southern California - EE 448 - Class #1Slide # 2

Course Personnel

Dr. Edward W. Maby (Instructor) [email protected] 740-4706 Office Hours: MW 1:00 - 2:00 PHE 626

Clint Colby [email protected]

Tyler Rather [email protected]


Grading Policy

Midterm 1 25% 17 February Midterm 2 25% 24 March Homework 15% Final Exam 35% 10 May

No Make-Up Exams Homework Conditions Borderline Grades Same “Curve” for Graduate Students


Course Objectives

Circuit Concepts for RF Systems Transmission Lines, Impedance Matching Noise and Distortion Analysis Filter Design

RF System Components Low-Noise Amplifiers, Power Amplifiers Mixers and Oscillators

Elementary Transmitter/Receiver Architectures and Their Board-Level Implementation


Why RF ?

Ever-Growing Wireless Applications Personal Communication Systems Satellite Systems Global Positioning Systems Wireless Local-Area Networks

Strong Demand for Wireless Engineers Digital is HOT Analog is COOL RF Design is an ART


Emphasis ???

Designing RF Integrated Circuits Some Engineers

Designing With RF Integrated Circuits More Engineers

Difficult to Satisfy Both Objectives


EE 448 Textbooks The Design of CMOS Radio-Frequency Integrated Circuits

Thomas H. Lee (required) Planar Microwave Engineering: A Practical Guide to Theory

Measurements and Circuits Thomas H. Lee

Radio Frequency Circuit Design W. Alan Davis and Krishna K. Agarwal

Advanced RF Engineering for Wireless Systems and Networks Arshad Hussain

Microwave and RF Design of Wireless Systems David M. Pozar

High-Frequency Techniques Joseph F. White


Some Good Advice …

Read the Syllabus Come to Class

(Come to Class Early) Do the Homework

(But Not One Hour Before a Deadline)

(And Don’t Give Up Easily) Enjoy the Course !


Basic Radio Systems

X

Modulator IF Filter Mixer

LocalOscillator

BandpassFilter

PowerAmplifier

Data In

X

LocalOscillator

BandpassFilter

Low-NoiseAmplifier

Mixer IF Filter

IFAmplifier

Demodulator

Transmitter

Receiver Data Out


Connecting the Boxes

Antenna RF Link Between Transmitter and Receiver

(Marginal Issue for EE 448) Transmission-Line Connections Between

Internal Transmitter/Receiver Components = Velocity / Frequency Circuit Dimensions Comparable to at High

Frequencies (>> 1 GHz) “Distributed” Circuit Behavior


Transmission-Line Model

Two “Wires” with Uniform Cross Section L (inductance), C (capacitance) per unit length

Transverse Electromagnetic Fields Quasi-Static Solutions L = L (, xy geometry), C = C (, xy geometry),

L C = R (resistance), G (conductance) per unit length (Consider Physical Mechanisms Later)


Telegraphers Equations

(Heaviside, 1880)


Power Implications

DissipatedPower

Change in StoredLinear Energy Density


Time-Domain Solutions

(No Loss)

Wave Equation

Forward Wave

Reverse Wave

Velocity

No Wave Dispersion (Corruption) During Propagation


Frequency Domain

v and i have Time Dependence

Propagation Constant

(Similar equation for i)

R and G may be dependent


Freq.-Domain Solutions

(V+ and V- are Fourier Amplitudes)

Similar form for i (z,t); however,

Characteristic Line Impedance

(Zo Follows Directly from Transmission-Line Model)

Forward Reverse


Low-Loss PropagationAssume (OK to 10 GHz)

• Attenuation in dB

• Attenuation in nepers

For Line Length l,


Velocities and Wavelength

Fixed Phase Angle

Phase Velocity:

Independent No Dispersion

Group Velocity:

(Applies to Modulated Signal)

Wavelength:


Historical Remarks

(Transatlantic Cable)

First Telegrapher’s Equations: (No L or G)

Prof. William Thomson (Later Lord Kelvin) 1854

DiffusionEquation

(Applies to Most Ordinary IC Interconnects)


Diffusion Solutions

Unit-Step Input:

For line length l, imax at

Pulse Input:


Diffusion “Velocity”

Sinusoidal Input:

“Velocity”

Dispersion, High-Frequency Attenuation


Did Engineers Care?

Dr. Edward Orange Wildman Whitehouse M.D.Chief Electrician, Atlantic Telegraph Company, 1856

“In all honesty, I am bound to answer, that I believe natureknows no such application of that law; and I can only regardit as a fiction of the schools, a forced and violent adaptationof a principle in Physics, good and true under other circum-stances, but misapplied here.”

On Thomson’s Results …

First Transatlantic Cable (1858)

Whitehouse: Long Cable Requires Large-Voltage Input 2000-V “Stroke of Lightning” per Pulse (Obviously)

Nahin, p. 34


What Happened Next?

Queen Victoria and James Buchanan Exchange Messages Great Celebration, Public Pleased Cable Insulation Fails, Cable Dead, Public Angry Boston Headline: Was the Atlantic Cable a Humbug? Investor: Was Cyrus Field an Inside Trader? Further Experiments: High Voltage Not Necessary

Whitehouse Fired Second Transatlantic Cable Successful (1866)


Minimal Dispersion ?

Telegraph Lines Make Poor Telephone Lines

(Bell Fails to Propagate Voice Over Atlantic Cable - 1877)

?

Heaviside (1887)

Increase L by Adding Series Loading Coils at /4 Intervals

Improve Audio Bandwidth, But Suppress High Frequencies

H88 Standard (88 mH at 6000-foot Intervals) Bad for DSL


Dispersion - Skin Effect

Skin Depth

Real Part: Amplitude DistortionImaginary Part: Phase Distortion

Rise Time


Dispersion - Dielectric Loss

Dielectric Constant Has Real and Imaginary Parts

(Loss Tangent)

Loss

General Relation for Capacitance:

Dielectric Loss Overtakes Skin-Depth Loss (f >> 1 GHz)


Digital Digression

Dispersion Promotes Inter-Symbol Interference

Equalization at Receiver Correct for Group Delay Correct for Amplitude Distortion Difficult for Very-High Data Rates

Pre-Emphasis (Pre-Distortion) at Transmitter Increase Pulse Amplitude After Transition MAX3292 (for RS-485) See Widmer et al. (IBM)

IEEE JSSC 31, 2004 (1996)


Why 50 Ohms?Consider Coaxial Cable With Inner and Outer Diameters a and b

Maximum Deliverable Power:

Zo = 30

Minimum Attenuation:

Zo = 77

Compromise: Zo = 50

(75 - Cable TV)

(Lee, pp. 229-231)


Microstrip Linesw

hSubstrate

Important Substrate Properties Relative Dielectric Constant Loss Tangent Thermal Conductivity Dielectric Strength

Numerous Design Equations for Zo and Effective See Davis and Agarwal, pp. 71-74; Chang, pp. 43-49 Calculator: http://mcalc.sourceforge.net/#calc


Design Formulas

Define

Then

Assumes “Narrow” Lines


References

Richard B. Adler, Lan Jen Chu, and Robert M. Fano, Electromagnetic Energy Transmission and Radiation (1960)

Paul J. Nahin, Oliver Heaviside: The Life, Work, and Times of an Electrical Genius of the Victorian Age (1988)

Henry M. Field, History of the Atlantic Telegraph (1866) Kai Chang, RF and Microwave Wireless Systems (2000) Richard E. Matick, Transmission Lines for Digital and

Communication Networks (1969)

(Other than course texts)

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