Non Linear Distortion and Dynamic Range Issues Non Linear Distortion - - PowerPoint PPT Presentation

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Non Linear Distortion and Dynamic Range Issues Non Linear Distortion and Dynamic Range Issues in the Design Of Microwave Electronics for in the Design Of Microwave Electronics for Communication and Remote Sensing Systems Communication and Remote Sensing Systems Alberto Alberto Santarelli Santarelli

Short course on:

RF electronics for wireless communication and remote sensing systems

Scuola di Dottorato in Scienze ed Ingegneria dell'Informazione Dottorato di Ricerca in Ingegneria Elettronica Informatica e delle Telecomunicazioni 13th, 14th and 20th July 2010, Facoltà di Ingegneria, Viale Risorgimento 2, Bologna

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Summary Summary

• Brief Overview of Wireless Systems
• Wireless T/R Front End Design Issues
• Non linear distortion, noise and dynamic-range issues in building

blocks of wireless communication and remote sensing systems.

• Trade-off issues between nonlinear distortion, output power and

power added efficiency in the design/optimization of microwave power amplifiers

• Basics of new generation electron devices for low-distortion, high-

dynamic-range microwave circuit design.

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Wireless Systems Overview (I) Wireless Systems Overview (I)

Wireless Cellular Telephone Network (Typ. Freq. : 950, 1800, 2100 MHz)

• (2G) GSM (mod. GMSK) - EDGE (mod. GMSK/8-PSK)
• (3G) UMTS (mod. QPSK)

– e.g. W-CDMA provides HSPA up to 7Mbs – Freq. Band 5MHz

• (3GPP) LTE (mod. QPSK, 16-QAM, 64-QAM)

– expected cell data rates of over 300 Mbps – Freq. Band up to 20 MHz

• (4G) IP-based, Software Defined Radio (SDR), Cognitive Radio (CR)

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Wireless Cellular Telephone Network Wireless Cellular Telephone Network

• Downlink (from BTS to Handset)
• Uplink (from Handset to BTS)

Base Terminal Station (BTS) Different specs and technologies used for uplink and downlink…

e.g. 16-QAM - S/Nreq=11dB Pout = 43 dBm e.g. QPSK - S/Nreq = 5dB Pout = 23 dBm

• Fig. from Ref.[1]

DL UL

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Wireless Systems Overview (II) Wireless Systems Overview (II)

Wireless Local/Personal Area Network (WLAN/WPAN) WiFi

• OFDM with subcarriers mod. PSK or QAM)
• based on the IEEE 802.11 standards
• Data rate up to 54 Mbit/s
• Freq.: 2.4 GHz, 5 GHz, Bandwidth up to 22 MHz

WiMax

• based on the IEEE 802.16 standard
• Multi-user channel access techniques such as OFDMA
• Peak data rates of 144 Mbit/s in downlink and 35 Mbit/s in uplink (802.16e)
• Freq. 2.3–2.5 GHz and the 3.4–3.5 GHz, Bandwidths up to 20 MHz

MIMO channels available (multiple TX/RX antennas, spatial diversity)

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Wireless Systems Overview (III) Wireless Systems Overview (III)

Wireless Sensor Networks

• Spatially distributed autonomous sensors
• Equipped with a radio transceiver
• r other wireless communications devices
• Small dimensions, low-power consumption,

low data rate, secure networking

• Typically based on the

IEEE 802.15.4 standard (WPAN) e.g. ZigBee in ISM radio bands and 2.4GHz

Super Node

Links to Other networks or Similar Super Nodes Motes

External Memory Digital I/O ports Radio Transceiver Analog I/O Ports Microcontroller

A/D D/A Sensor Sensor

External Memory Digital I/O ports Radio Transceiver Analog I/O Ports Microcontroller

A/D D/A

Microcontroller

A/D D/A Sensor Sensor

Mote

Power Supply

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Wireless Systems Overview (IV) Wireless Systems Overview (IV)

Back-Haul – Terrestrial and Satellite Communications

• Point-to-Point Terrestrial or via-Satellite Microwave Radio Links

(e.g. connecting Base Stations)

– dedicated high-capacitive terrestrial radio links at 38 GHz (mod. PSK/QAM)

• Point-to-Multipoint Microwave Access Technologies

(broadband, fixed wireless, point-to-multipoint technology)

– WiMax – Local Multipoint Distribution Service (LMDS) at 28-29 GHz (PSK/QAM)

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Wireless Systems Overview (V) Wireless Systems Overview (V)

Not only networks… Satellite Remote Sensing and Communication

• Synthetic Aperture Radars
• Altimeters and radiometer applications
• Radioastronomy
• Satellite Radio Links for video, audio and data broadcasting (DVB-

S/S2) and Internet Access at 12GHz (downlink) and 18 GHz (uplink) (mod. BPSK, 16APSK and 32APSK) Frequency Bands: C – X – Ku and beyond… Reliability issues…

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Basic Building Blocks of RF Front Basic Building Blocks of RF Front-

• Ends

Ends

• Power Amplifier (PA) – provides signal power amplification just

before the transmitting antenna

• Low Noise Amplifier (LNA) – provides amplification just after the

receiving antenna by introducing minimal S/N degradation

• Mixer – provides up and down frequency conversion of signals
• Local Oscillator – provides sinusoidal waveform for carrier

generation

• Frequency Synthesizer – Provides stable and programmable carrier

generation and recovery

• Linear Filters and Phase Shifters– for band and channel selection,

image rejection, IQ modulation, etc.

• Duplexer - allows using a single antenna for TX/RX

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Duplexing Duplexing

• Single antenna for RX and TX
• Time Division Duplexing (TDD) vs.

Frequency Division Duplexing (FDD)

• RX has to be isolated from high power

generated by HPA (otherwise: LNA desensitisation)

Half- duplex Full- duplex

• Figs. from Ref. 2

FDD

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Mixer Mixer

( ) cos

LO LO LO

v t V t ω = ( ) cos

S S S

v t V t ω =

( ) ( )

( ) cos cos 2 2

• ut

LO S LO S LO S LO S

A A v t V V t V V t ω ω ω ω = + + −

The mixer ideally executes a perfect multiplication of two input signals vA, vB The Mixer provides Frequency Conversion Up-conversion Down-conversion

( )

LO

v t ( )

S

v t ( )

• ut

v t ( ) ( ) ( )

• ut

LO S

v t A v t v t = ⋅ ⋅

• Actual Mixers suffer from noise and distortion

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Example of a Microwave T/R Front Example of a Microwave T/R Front-

• End

End

• Fig. from Ref. 2

Lucent Tech. GSM Transceiver

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Typical Trends in T/R Front Typical Trends in T/R Front-

• End Architectures

End Architectures

• ADC and DAC progressively shift towards the antenna

(Software Defined Radio)

• Reconfigurable building blocks

(“frequency-agile” RF components and systems)

Digital RF circuits Analog RF circuits with digital control (e.g. with use of RF-MEMS)

• High-efficiency

PA schemes (Doherty Amplifiers, Class-S Amplifiers, Envelope Tracking,…)

• Fig. from Ref. 1

Linearity ??? PA Linearization techniques

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Limiting Factors of Nonlinear RF Building Blocks Limiting Factors of Nonlinear RF Building Blocks

• Broad-band and Parametric Noise
• Nonlinear Distortion
• Component Dynamics cannot be neglected at microwaves
• Power consumption (energetic efficiency, self-heating, reliability)
• Transmission of Wide-Band signals leads to critical requirements for the Receivers in

terms of robustness against strong Interfering Signals

• Flexibility and Reconfigurability

DYNAMIC RANGE Nonlinear RF building blocks of T/R Front Ends (PA, LNA, Mixer, Oscillator and Frequency Syntethasizer) are basically limited in performance by

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Noise in Electrical Components Noise in Electrical Components

• Broad-Band (Additive) Noise

(e.g. Thermal, Diffusion/Shot-Noise)

– Due to fluctuations of carrier velocity – Broad-Band White Power Spectral Density (PSD)

• Parametric (Modulating) Noise

(e.g. 1/f Flicker Noise, G-R Noise)

– Due to fluctuations of carrier population – Low Frequency-Generated (LFG) Noise – “Colored” PSD – Converted to RF by multiplicative mixing phenomena Broad-Band Noise 1/f Noise PSD(f) f fC

Corner Frequency HBTs :1-100 KHz FETs: 1-10 MHz Two basic kind of noise exist in electrical components:

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Effects of Noise on T/R Front Effects of Noise on T/R Front-

• End Performance

End Performance

• Phase Noise of the locally generated oscillation: carrier generation with

inherent spurious “noisy” modulation

• Same problem both in the Transmitter and in the Receiver (Carrier

Recovery)

• No benefit from increasing signal power since phase noise side-band

amplitude also increases proportionally (non additive, but modulation noise) Phase Noise Broad-Band Noise

• Sensitivity (and dynamic range) reduction of the Low Noise Amplifier
• Noise Figure degradation due to strong adjacent interfering signals

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At microwave frequencies (presence of reactive phenomena) the Power Amplifier is nonlinear with memory Linear With Memory:

Nonlinear with Memory: Nonlinear Memory-less: ( ) ( ) ( )

M

T

y t h x t d τ τ τ = −

• 1

1 1 1 2 1 2 1 2 1 2 3 1 2 3 1 2 3 1 2 3

( ) ( ) ( ) ( , ) ( ) ( ) ( , , ) ( ) ( ) ( )

M

T

y t h x t d h x t x t d d h x t x t x t d d d τ τ τ τ τ τ τ τ τ τ τ τ τ τ τ τ τ τ = − + + − − + + − − − + +

• 2

3 2 3

( ) [ ( )] ( ) ( ) ( ) y t f x t x t x t x t α α α

1

= = + + +

VOLTERRA SERIES

Distortion in Nonlinear Components (focus on PA) Distortion in Nonlinear Components (focus on PA)

PA x(t) y(t) Which description for the PA ?

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A Simplified Description of A Simplified Description of PAs PAs

• Volterra kernels h1(τ1), h2(τ1, τ2), h3(τ1, τ2, τ3),… completely characterize

the amplifier nonlinear dynamic response

• Volterra series can be practically used only for weak non-linearity, since

kernels measurement at microwave frequencies is difficult

• Modified Volterra Series descriptions exist. They are based on modified kernels

and are more suited for practically dealing with weak and strong nonlinearities However…

• For a simplified analysis of nonlinear distortion in power amplifiers a purely

memory-less power amplifier is assumed in the following Simplified Analysis

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Nonlinear Distortion Characterization Nonlinear Distortion Characterization

• Harmonic Distortion
• Gain compression

(Pout vs. Pin, Power Gain vs. Pin)

• Intermodulation Distortion
• AM/AM and AM/PM plots

(Complex Gain vs. Pin, Describing Function Approach) Nonlinear Distortion has been traditionally characterized by means of: More recently-introduced FoM for dealing specifically with Wireless Systems:

• NPR (Noise Power Ratio)
• EVM (Error Vector Magnitude)
• ACPR/ACLR (Adjacent Channel

Power/Leackage Ratio

• …

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Harmonic Distortion (I) Harmonic Distortion (I)

Single Single-

• Tone Sinusoidal Excitation

Tone Sinusoidal Excitation ( ) cos( ) x t X t ω =

2 3 2 3

( ) [ ( )] ( ) ( ) ( ) y t f x t x t x t x t α α α

1

= = + + +

• |X()|

|Y()| 02030 ….

PA Memory-less Model: Input PA Excitation: PA Output:

( )

1

( ) [ ( )] cos

AC DC k k

y t f x t X X k t ω

∞ − =

= = + ⋅

• Spectral re-growth at Harmonic (angular) Frequencies: k0t

SPECTRUM ANALYZER SIN. GEN.

PA x(t) y(t) Scalar Measurement

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Harmonic Distortion (II) Harmonic Distortion (II)

• Very simple

but scarcely meaningful for microwave communications

• Out-of-band harmonics only

(output filtering possible)

• Results can be too optimistic

(selective output matching networks = harmonic filtering)

• Non realistic input test signal

(constant amplitude carrier, no modulation, zero bandwidth)

• Fig. from Ref. 3

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Harmonic Distortion (III) Harmonic Distortion (III)

Typical Plots Typical Plots

Pout versus Pin Transducer Power Gain vs. Pin 1dB

• 1dB (3dB) Compression Point

Pout1dB Pin1dB

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Intermodulation Intermodulation Distortion (I) Distortion (I)

Two Two-

• Tone Sinusoidal Excitation

Tone Sinusoidal Excitation

1 2

( ) cos( ) cos( ) x t X t X t ω ω = +

• PA Memory-less Model:

Input PA Excitation: PA Output:

( )

, 1 2 ,

( ) [ ( )] cos

AC DC m n m n

y t f x t X X m t n t ω ω

−

= = + ⋅ +

• Spectral re-growth at Harmonic (angular) Frequencies: m1t+n2t

Scalar Measurement

SPECTRUM ANALYZER SIN. GEN.

PA x(t) y(t)

SIN. GEN.

+

1 2

SMALL TONE SPACING: ∆ ∆ ∆ ∆ = 2-1<< 0 |X()| 1 2

2 3 2 3

( ) [ ( )] ( ) ( ) ( ) y t f x t x t x t x t α α α

1

= = + + +

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1 1 2 3 3 1 2

( ) [cos( ) cos( )] 3 [cos(( ) ) cos(( ) )] 4

• ut-of-band terms

in-band higher order (odd) w t X t t X t t α ω ω α ω ω ω ω = ⋅ + + + ⋅ − ∆ + + ∆ + + + +

In mild large-signal operation intermodulation distortion is mainly due to 3rd order non-linearity

3 3 3

1 6 d f dx α =

Intermodulation Intermodulation Distortion (II) Distortion (II)

• Fig. from Ref. 3

1 2 1 2 1 2

2 2 ω ω ω ω ω ω ω ω − = − ∆ − = + ∆

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1 3 3

IMD [dBc] P C I P = =

1 2

∆ ∆ ∆ ∆ ∆ ∆ ∆ ∆ ∆ ∆ ∆ ∆

P1 P3 3rd-order IMD product

(in-band: co-channel distortion)

|X()|

• |Y()|

P5 5th-order IMD product

(out-band: adjacent channel distortion) Channel Bandwidth Excitation Tones

• Intermodulation

Intermodulation Distortion (III) Distortion (III)

Carrier to Interference Ratio (CIR)

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Intermodulation Intermodulation Distortion (IV) Distortion (IV)

• Co-channel and Adjacent Channel Distortion Evaluation
• Input test signal with non-zero bandwidth (amplitude and phase modulation)
• Quite simple measurement set-up
• Scalar Measurement

A closer look to the two-tone excitation… 0 = central carrier frequency Ex(t) = complex modulation envelope

{ }

( ) Re ( )

j t x

x t E t e ω = ⋅

2 2 1 2

( )

j t j t x

E t X e X e

ω ω ∆ ∆ −

= ⋅ + ⋅

EX(t) has variable amplitude and phase:

1 2

( )

x

E t X X ≤ ≤ + ( ) 2

x

E t π ≤ ∠ ≤

GOOD SIGNAL FOR NONLINEAR TESTING

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OUTPUT IP3 INPUT IP3 1 3 High-linearity amplifier:

3 1

• 30
• 40 dBc

P P = ÷ 3 1 3 3 2 P P OIP ⋅ − =

Third Third-

• Order Intercept Point (IP3)

Order Intercept Point (IP3)

Alternative way of expressing the PA distortion specification

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Modulated input signal: Output signal (neglecting out-of-band harmonics, but including both co-channel and adjacent channel interference): Ex(t), Ey(t) are slowly time-varying when modulated signal bandwidth BW<<0 QUASI-STATIC AMPLIFIER DESCRIPTION No memory on signal modulation envelopes but PA complex response considered at 0 G is a complex Describing Function

• nly dependent on |Ex(t)| since PA is a

time-invariant non-linear system

{ }

( ) Re ( )

j t x

x t E t e ω = ⋅

{ }

( ) Re ( )

j t y

y t E t e ω = ⋅ ( ) , ( ) ( )

y x x

E t G E t E t ω =

• ⋅
• Describing Function Model of

Describing Function Model of PAs PAs

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can be measured (vector voltmeter)

• r computed (HB) under amplitude-swept

sinusoidal excitation

• G [0,|Ex(t)|] completely describes the nonlinear amplifier response to any

signal x(t) with relatively small bandwidth BW<< 0

• SCALAR GAIN COMPRESSION (1dB) NOT SUFFICIENT !

no AM/PM conversion;

y x

E G E =

J G

G G e ∠ = ⋅

AM/AM conversion AM/PM conversion

|Ex| |G| G ∠ |Ex|

Complex Describing Function

AM/AM AM/AM -

• AM/PM PA Behavioral Model

AM/PM PA Behavioral Model

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Adjacent Channel Power Ratio (ACPR) Adjacent Channel Power Ratio (ACPR)

Quantifying PA performance in the final application Adjacent Channel Power Ratio (ACPR)

SPECTRUM ANALYZER (W)-CDMA Modulated Source

PA x(t) y(t)

( ) ( )

Bin Bou y y t

PDF f df ACPR PDF f df ⋅ = ⋅

• Bout

Bin Different definitions of Bin Bout depending on the Ref. Std.

• Fig. from Ref. 4
• Fig. from Ref. 5

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Noise Power Ratio (NPR) Noise Power Ratio (NPR)

• Used initially for characterizing multi-carrier

power amplifiers

• A broad-band Additive Gaussian White Noise

(AGWN) source is used to simulate the presence of many carriers of random amplitude and phase

• Band-pass Filtering approximately equal to the

Channel Bandwidth

• Equivalent to: (C+I)/I

SPECTRUM ANALYZER AGWN Source

PA x(t) y(t)

Notch Filter Band- pass Filter

• Fig. from Ref. 6

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Error Vector Magnitude (EVM) Error Vector Magnitude (EVM)

Vector Signal Analyzer Digitally Modulated Source

PA x(t) y(t)

• PA Specifications often given in terms of peak and rms value of the EVM
• Figs. from Ref. 7

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• Specs. of various Wireless Systems (example)
• Specs. of various Wireless Systems (example)
• Fig. from Ref. 8

ACPR

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Energetic Efficiency Energetic Efficiency

PA x(t) y(t)

RF

• ut

P

RF in

P

DC in

P

Power Added Efficiency

RF RF

• ut

in DC RF in in

P P PAE P P − = +

Energetic Efficiency

RF

• ut

DC RF in in

P P P η = +

In the presence of an modulated signal, efficiency becomes a function of the instantaneous signal envelope amplitude Average Energetic Efficiency

RF

• ut

DC RF in in

P P P η = +

where, for instance:

( )

RF

• ut

y y y

P P E E dE = ⋅

• p(E) Probability Density Function of the Envelope Amplitude
• Fig. from Ref. 8

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Thermal Aspects (PA Self Thermal Aspects (PA Self-

• Heating)

Heating)

Power dissipated into the device:

(time-dependent quantity due to the inst. variations of the Env. Amplitude)

• High-Efficiency is needed for limiting the Internal Device Temperature
• Peak and Average Internal Device Temperature must be kept under tolerable

limits for reliability

• Proper design of the assembly structures for optimal heat extraction (package)

1 1

DC RF RF RF D in in

• ut
• ut

P P P P P η

• =

+ − = ⋅ −

• Internal Device

Temperature: (thought as spatially averaged along the FET channel) Channel-to-Back-Side Thermal Resistance [W/° C] B D

T T R P

ϑ

= + ⋅

Wafer Back-Side Temperature

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Linearity vs. Efficiency Trade Linearity vs. Efficiency Trade-

• off
• ff
• In many power amplifier (e.g. class-A/AB) the maximum efficiency is obtained

for peak output power corresponding to a maximum of tolerable distortion

• Whenever the instantaneous input signal envelope amplitude corresponds to

input power lower than PEP the efficiency dramatically drops

• Constraints on PA distortion often lead to choose: PEP << Pin1dB (BACK-OFF)

[dBm]

PEP RF Output Power [dBm]

RF in

P

RF

• ut

P

ˆ RF

• ut

P

[dBm]

DC input Power [W]

RF in

P

DC in

P

PEP

η

Efficiency [%]

[dBm]

RF in

P ˆ η

PEP

(Peak Envelope Power – PEP)

• Figs. from Ref. 8

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Peak to Average Ratio (PAR) Peak to Average Ratio (PAR)

• High-spectral-efficiency modulation

schemes are characterized by large PARs (or crest factor)

• The same happens when a large number of independently modulated sub-

carriers are added to form the signal to be transmitted (such as with OFDM)

• PA average energetic efficiency

may become extremely low in the presence of large PARs combined with power back-off

• Dedicated PA solutions needed

(e.g. Doherty Amplifier)

PAR (typ.) [dB]

• Mod. (examples)

12 OFDM 10.6 W-CDMA (DL carrier) 7.7 64-QAM 3.5-4 QPSK

( ) ( )

v peak v rms

t PAR t = E E

• v

E Complex envelope

• f the modulated signal

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Effects of Noise and Distortion in LNA and Mixers Effects of Noise and Distortion in LNA and Mixers

Noise Floor (Broad-band noise) Strongest Signal limited by: Weakest signal detected limited by: Nonlinear Distortion (e.g. P1dB, P3dB) DYNAMIC RANGE

[ ] 30 10log( )

dB

Noise Floor Input dBm kTB NF = + +

Spurious Free Dynamic Range (SFDR) (upper power limit corresponds to 3°

• order

Intermodulation Product equal to the Noise Floor)

DR IS CRITICAL IN WIDEBAND WIRELESS SYSTEMS DUE TO LINEARITY CONSTRAINTS AND STRONG INTERFERING ENVIRONMENT

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The Doherty Power Amplifier (I) The Doherty Power Amplifier (I)

• Two PAs combined

– Carrier PA (class-B) – Peaking PA (class-C)

• Only Carrier PA is working for

small input signal envelope amplitude (e.g. Pin < ⋅ PEP with 0.25<<0.5)

• Max. efficiency of the Carrier PA is

achieved at Pin = ⋅ PEP (ideally 78.5%)

• Both PAs contribute output power for Pin > ⋅ PEP
• Equivalent load impedances vary with increasing envelope amplitude (ZLCarrier ↓,

ZLPeaking ↑) implementing a sort of “active load-pulling” mechanism

• Both PAs deliver 50% of output power at PEP
• Fig. from Ref. 8

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The Doherty Power Amplifier (II) The Doherty Power Amplifier (II)

• Average efficiencies nearly doubled

at equal ACPR

• Lower are chosen for high-PAR signals
• Limitations exist with UWB signals due to
• freq. selective matching networks and

transmission lines

S-Band TX

50W – Si-LDMOS IS-95 CDMA

• Figs. from Ref. 8

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Other Efficiency Enhancement Techniques Other Efficiency Enhancement Techniques

Limitations with UWB signals due to the limited bandwidth of the Bias Modulator (DC/DC converter) Envelope Elimination and Restoration (EER) (Final PA stage operating

in class-C/D/E/F)

Techniques based on “Bias Modulation” Envelope Tracking (ET) (Final PA stage operating

in class-A/AB)

• Figs. from Ref. 8

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PA Linearization Techniques PA Linearization Techniques

• FeedBack
• FeedForward
• Predistortion

Three main families of PA Linearization Techniques: Example: (DIGITAL) PREDISTORTION Red: Unlin. PA Blue: Linearized PA

• Figs. from Ref. 8, 9

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• Conflicting requirements on output power, efficiency and high linearity
• Search for optimal values of source/load impedances,

bias conditions, bias networks, non-linearity compensating structures, etc

• Device technology suitably chosen according to frequency, output power,…
• Source/Load-pull device characterization

(IMD, output power, power-added-efficiency plots)

• Numerical simulation with suitable non-linear transistor models and CAD tools

(Harmonic Balance, Transient Simulation, Envelope Simulation)

DESIGN TOOLS

PA Design PA Design

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• 1
• 0.5

0.5 1

• 1
• 0.5

0.5 1 20 40 60 80 4 40 50 50

• 1
• 0.5

0.5 1

• 1
• 0.5

0.5 1 20 40 60 80 4 40 50 50

Output Power (1st Harmonic)

Source/Load Pull PA Characterization Source/Load Pull PA Characterization

Plots of main FoM versus input/output reflection coefficients (impedances)

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Nonlinear Transistor Models Nonlinear Transistor Models

Physics-based models: derived by physical principles applied to the device structure

• Direct link between technological process parameters (materials,

geometry, doping profile,…) and electrical response

• More suitable for device design/analysis

Empirical Compact Models: measurements based e.g. Equivalent Circuits use of lumped circuital elements to describe measured characteristics

• Numerically efficient
• Widely used for MMIC and HMIC design

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IC Technologies for T/R Front IC Technologies for T/R Front-

• Ends

Ends

• Base-Band Processing:

CMOS

• RF Front-Ends in Handset and Portable Devices (Pout < 1W):

SiGe HBT (BiCMOS Integrated Circuits), CMOS, BJT

• RF Front-Ends in Base-Stations (Pout ~ 10-100 W):

Si-LDMOS, GaN-HEMT Wireless Back-Haul, Satellite Links, Space Radio-Astronomy, Radars (GHz<f<THz)

• GaAs-PHEMT, GaN-HEMT, GaAs-HBT, InP-PHEMT

Transistors may be available for: Mixed Analog/Digital Integrated Circuits, MMIC Design,

• r in Package or Die for Hybrid Solutions

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PAs PAs for Handsets (Technology Overview for Handsets (Technology Overview -

• Dec

Dec ‘ ‘09) 09)

• Fig. from Ref. 10

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SiGe SiGe Heterojunction Heterojunction Bipolar Transistor (HBT) Bipolar Transistor (HBT)

• Similar to well-known BJT, but the Base region is implemented by

SiGe instead of Si by creating hetero-junctions (H-J).

• Due to the specific properties of H-J, electron injection efficiency is

strongly improved even in the presence of a heavily doped Base

• Very small parasitic effects

(and Base resistance) obtained also thanks to the high Base doping

• Extremely good Transition Frequency

(frequency at unity current gain with short-circuited output)

• Integration with Standard CMOS

processes (BiCMOS)

• Fig. from Ref. 11

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BiCMOS BiCMOS (Si (Si-

• CMOS+SiGe

CMOS+SiGe HBT) Technology HBT) Technology

• Fig. from Ref. 12 (NEC)

0.18-um RF SiGe BiCMOS

• Analog, RF and Digital Circuit Integrated into a single IC Process
• Most suited technology for the Software Defined Radio
• SiGe-HBT offers very low-noise (both 1/f and broad-band)
• Highly reliable

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High High Power Power MOSFETs MOSFETs – – Si Si-

• LDMOS

LDMOS

• Wide low-doped Drift

Drain region for high Break-Down Voltage

• Wide channel widths

(distributed structures) for High Drain Currents

• Output Power:

tens/hundreds of Watt

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High Electron Mobility Transistors (HEMT) High Electron Mobility Transistors (HEMT)

• Hetero-Junction (H-J)

between AlGaN and GaN layers

• N-Channel confined in a very

shallow, almost bi-dimensional region into the intrinsic-GaN

• Extremely high mobility of

carriers in the intrinsic GaN

• Devices obtained with high

Break-down voltages (~100V), high power densities (5W/mm)

• SiC or Sapphire substrates
• Quite expensive but extremely

promising technology

• Fig. from Ref. 13

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A A GaN GaN Foundry Example: Foundry Example: TriQuint TriQuint

• Fig. from Ref. 14

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GaAs GaAs-

• based

based Technologies ( Technologies (Example Example:UMS) :UMS)

• Fig. from Ref. 15

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GaAs GaAs-

• based

based Technologies ( Technologies (Example Example: UMS) : UMS)

• Fig. from Ref. 15

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Figure References Figure References

1.

• G. Fisher, “Next-Generation Base Station Radio Frequency Architecture”, Wiley Bell Labs Technical Journal, Vol

12 , N. 2, Aug 2007 2.

• B. Razavi, “RF microelectronics “, Prentice Hall, 1997

3.

• P. Wambacq, W. Sansen, “Distortion Analysis of Analog Integrated Circuits”, Kluver Academic Press, 1998

4. Agilent AN 1307,” Testing CDMA Base Station Amplifiers”, Application Note, 2000 5. “Adjacent Channel Power Ratio (ACPR)”, Application Note, Anritsu, 2001 6.

• K. M. Gharaibeh, K. G. Gard, M. B. Steer, “The Applicability of Noise Power Ratio (NPR) in Real Communication

Signals”, ARFTG Conference, 2006 67th , vol., no., pp.251-253, 16-16 June 2006 7. Agilent PN 89400-14, “Using Error Vector Magnitude Measurements to Analyze and Troubleshoot Vector- Modulated Signals”, Product Note, 2000 8.

• F. H. Raab, P. Asbeck, S. Cripps, P. B. Kenington, Z. B. Popovic, N. Pothecary, J. F. Sevic and N. O. Sokal, “RF

and Microwave Power Amplifier and Transmitter Technologies. Part I-II-III-IV”, High Frequency Electronics, Summit Technical Media, LLC, May 2003 9. W.-J. Kim, S. P. Stapleton, J. H. Kim, C. Edelman, “Digital Predistortion Linearizes Wireless Power Amplifiers”, IEEE Microwave Magazine, Sep 2005. 10.

• J. Choi, D. Kang, D. Kim, J. Park, B. Jin, and B. Kim, “Power Amplifiers and Transmitters for Next Generation

Mobile Handsets”, Journ. Of Semiconductor Technology And Science, Vol.9, N.4, Dec 2009. 11. J.-S. Rieh , "A brief overview of modern high-speed SiGe HBTs," 8th Int- Conf. on Solid-State and Int. Circ. Tech., ICSICT '06, pp.170-173, Oct. 2006. 12.

• F. Sato, T. Hashimoto, H. Fujii, H. Yoshida, H. Suzuki, T. Yamazaki, “A 0.18-um RF SiGe BiCMOS Technology

With Collector-Epi-Free Double-Poly Self-Aligned HBTs”, IEEE Trans. On Elect. Dev., Vol.50, N.3, Mar. 2003. 13.

• S. Zhong, T. Chen, C. Ren, G. Jiao, C. Chen, K. Shao, N. Yang, “AlGaN/GaN HEMT with over 110 W Output

Power for X-Band”, Proc. of the 3rd European Micr. Int. Circ. Conf. (EuMIC’08), Oct 2008. 14. http://www.triquint.com 15. http://www.ums-gaas.com