Download - Introduction to RF & Wireless - Part 2
Introduction to RF & Wireless
Two Day Seminar
Module 2
Introduction to RF & Wireless
Two Day Seminar
Module 2
Course AgendaDay One
• Morning (Module 1)– Introduction to RF
• Afternoon (Module 2)– RF hardware
Day Two• Morning (Module 3)
– Older systems & mobile telephony
• Afternoon (Module 4)– Newer systems & the future
Module 2 - RF Hardware
1. Basic Building Blocks
2. Other Components
3. Circuits
Module 2 - RF Hardware
1. Basic Building Blocks
2. Other Components
3. Circuits
1. Basic Building Blocks
Transmitter/Receiver Preview
Antennas
Amplifiers
Filters
Mixers
Sources
Transmitter/Receiver Review
1. Basic Building Blocks
Transmitter/Receiver PreviewAntennas
Amplifiers
Filters
Mixers
Sources
Transmitter/Receiver Review
Basics Building Blocks - Transmitter/Receiver Preview
Transmitters & Receivers
Recall
Transmitter Block Diagram
Receiver Block Diagram
1. Basic Building Blocks
Transmitter/Receiver Preview
AntennasAmplifiers
Filters
Mixers
Sources
Transmitter/Receiver Review
Basic Building Blocks - Antennas
Antennas
Basic Building Blocks - Antennas
Antennas
Function Turn current on a wire into airborne waves Vice versa
• Most antennas work in both directions
Antennas
What Act as impedance matching circuits
• From conductor (50 ohms) to free space (377 ohms)
Free space377 ohms
Conductor50 ohms
Antenna
Antennas
How Conductors that are about ½ wavelength long
begin to radiate RF energy as waves
½ Wavelength
Wavelengths Wavelength (meters) Application
5,000,000 Electrical wall outlet
152,500 The human voice
566 AM radio
5 VHF television
3 FM radio
0.3 Cellular phones
0.1 PCS phones
0.02 DirectTV
Basic Building Blocks - Antennas
Antennas
Characteristics Active: Requires a power supply Passive: Does not require a power supply Directional: Sends RF energy in one direction Omnidirctional: Sends RF energy in all directions Size: Depends on the wavelength Shape: Depends on the direction of the RF energy
Basic Building Blocks - Antennas
Antenna Pattern
What Is It? An engineering tool that shows a birds-eye view of
the RF energy radiating out of an antenna
Basic Building Blocks - Antennas
Antenna Pattern
Omnidirectional
Basic Building Blocks - Antennas
Antenna Pattern
Directional
20
Beamwidth
Azimuth
Basic Building Blocks - Antennas
Gain
Two Kinds Power gain
• Comes from an amplifier
• Increases the power
Antenna gain• Directional gain
• No increase in power
Basic Building Blocks - Antennas
Isotropic Antenna
What Is It? A mythical "point" antenna
• Antenna pattern is a sphere• Minimum power density
Basic Building Blocks - Antennas
Directional Antenna
Visual Depiction Higher power density
than isotropic
Basic Building Blocks - Antennas
Antenna Gain
Directional Gain A gain in power density NOT power
• Relative to an isotropic antenna
Measured in dBi
Definition dBi = "dB greater than isotropic"
Basic Building Blocks - Antennas
Antenna Gain
For ExampleAn directional antenna with 10 dBi of antenna gain produces an RF signal with TEN TIMES the power density compared to an isotropic antenna
Basic Building Blocks - Antennas
Antenna Gain
Input power = 30 dBm
Output power =10 dBi
30 dBm
Effective Isotropic Radiated Power = 30 dBm + 10 dBi = 40 dBm
Noise floor -120 dBm
Output power40 dBm
Free space loss
-80 dBm
120 dB
Absorption-90 dBm
10 dB
30 dBS/N
Noise floor -120 dBm
Effective isotropicradiated power 40 dBm
Free space loss
-80 dBm
120 dB
Absorption-90 dBm
10 dB
30 dBS/N
Noise floor -120 dBm
Effective isotropicradiated power 40 dBm
Free space loss
-80 dBm
120 dB
Absorption 10 dB
40 dBS/N
Ant gain
Basic Building Blocks - Antennas
Antenna Gain
30 dBm Antenna10 dBi
Antenna10 dBi
FSL-120 dB
Absorb-10 dB
-80 dBm
Noise floor -120 dBm
40 dBS/N
Basic Building Blocks - Antennas
Antenna Gain
Even Omnidirectionals Have Gain 2 - 3 dBi
Antenna Types
Omnidirectional Dipole: ½ wavelength long Monopole: ¼ wavelength long
Directional Dish Horn Patch Array
Array Antenna
Polarization
What Is It? The RF (sine) waves which emanate from an
antenna have an orientation to them• Horizontal
• Vertical
Basic Building Blocks - Antennas
Polarization
Horizontal Vertical
Basic Building Blocks - Antennas
Polarization
So What Otherwise identical RF signals can be made
distinct by having different polarizations• Better use of scarce bandwidth
• Polarization diversity
Basic Building Blocks - Antennas
Smart Antennas
What Are They? Directional antennas in which the antenna beam moves
Basic Building Blocks - Antennas
Smart Antennas
What Are They? Directional antennas in which the antenna beam moves
Basic Building Blocks - Antennas
Smart Antennas
What Are They? Directional antennas in which the antenna beam moves
Basic Building Blocks - Antennas
Smart Antennas
What Are They? Directional antennas in which the antenna beam moves
Basic Building Blocks - Antennas
Smart Antennas
How? Switched beam Electronically scanned
Why? More users per area Spatial division multiple access
1. Basic Building Blocks
Transmitter/Receiver Preview
Antennas
AmplifiersFilters
Mixers
Sources
Transmitter/Receiver Review
Basic Building Blocks - Amplifiers
Amplifiers
Basic Building Blocks - Amplifiers
Amplifiers
Function Increase the power of RF signals
• "Power gain"
Basic Building Blocks - Amplifiers
Amplifiers
Main Types Low noise amplifier (LNA)
• First one in a receiver
High power amplifier (HPA)• Last one in a transmitter
Other• Many different kinds
• "Gain blocks"
Amplifiers
HPA LNA
Other
Basic Building Blocks - Amplifiers
Amplifier Properties
LNA Gain Linearity Noise figure
HPA Gain Linearity Output power
Basic Building Blocks - Amplifiers
Gain
Power Gain (Gp) Measured in dB
30 dB
-90 dBm
-60 dBm
Linearity
Transfer CurveOne dB compression point
Basic Building Blocks - Amplifiers
Linearity
Another Measure Third order intercept (Ip3)
Intercept point• Measured in dB
Basic Building Blocks - Amplifiers
Output Power
Dictates Amplifier Performance Suppose Psat = 40 dBm
30 dB
20 dBm
50 dBm
HPA
Basic Building Blocks - Amplifiers
Output Power
Dictates Amplifier Performance Suppose Psat = 40 dBm
30 dB
20 dBm
50 dBm
Basic Building Blocks - Amplifiers
Output Power
Dictates Amplifier Performance Suppose Psat = 40 dBm
30 dB
20 dBm
40 dBm
Basic Building Blocks - Amplifiers
Output Power
Dictates Amplifier Performance Suppose Psat = 40 dBm
30 dB
20 dBm
40 dBm
20 dB
Basic Building Blocks - Amplifiers
Noise Figure
Definition How much an amplifier decreases the S/N ratio
• Measured in dB
NF=3dB40 dBS/N 37 dBS/N
LNA
Basic Building Blocks - Amplifiers
A Special Amplifier
Variable Gain Amplifier (VGA) Gain can be made to vary
15 dB
Basic Building Blocks - Amplifiers
A Special Amplifier
Variable Gain Amplifier (VGA) Gain can be made to vary
30 dB
1. Basic Building Blocks
Transmitter/Receiver Preview
Antennas
Amplifiers
FiltersMixers
Sources
Transmitter/Receiver Review
Basic Building Blocks - Filters
Filters
Basic Building Blocks - Filters
Filters
Function Eliminate signals at unwanted frequencies
Basic Building Blocks - Filters
Filters
Block Diagrams
Filters
Frequency Response Used to describe a filter's behavior A graph of attenuation vs frequency
Filters
Types Low pass
• Only signals below a certain frequency can pass
High pass• Only signals above a certain frequency can pass
Band pass• Only signals between two frequencies can pass
Band reject ("Notch")• Only signals outside two frequencies can pass
Low Pass Filter
Ideal Frequency Response
Pass band
Stop band
Low Pass Filter
Real Frequency Response
Pass band
Stop band
Low Pass Filter
Real Frequency Response
Out of band signalsIdealpassband
High Pass Filter
Frequency Response
Band Pass Filter
Frequency Response
Band Reject Filter
Frequency Response
Special Filters
Duplexer ("Diplexer") Two band pass filters in one package
Special Filters
Duplexer Frequency Response
Basic Building Blocks - Filters
Special Filters
SAW (Surface Acoustic Wave) Converts RF signals into sound signals Used for low frequency applications
• Typically less than 3 GHz
Very small and low cost• Ideal for use in cell phones
Basic Building Blocks - Filters
Special Filters
Superconducting Filters Have zero insertion loss in the pass band Have a near-vertical frequency response Require cooling units
• Used primarily in cellular base station receivers
Basics Building Blocks - Filters
Filters
Interesting Things To Know All devices have a 1 dB compression point -
even passive ones like filters• A function of input power
IL of a passive device is its noise figure
1. Basic Building Blocks
Transmitter/Receiver Preview
Antennas
Amplifiers
Filters
MixersSources
Transmitter/Receiver Review
Basics Building Blocks - Mixers
Mixers
Basics Building Blocks - Mixers
Mixers
Function To change the frequency of the RF signal
Basics Building Blocks - Mixers
Mixers
How Mixers have two inputs and one output called ports
Input 1
Input 2
Output
Basics Building Blocks - Mixers
Mixers
How One RF signal goes into Input 1 One RF signal goes into Input 2 TWO RF signals come out of the Output
Basics Building Blocks - Mixers
Mixers
How Output signal 1
• Frequency = sum of frequencies of input signals
Output signal 2• Frequency = difference of frequencies of input signals
Basics Building Blocks - Mixers
Mixers
ExampleOne input signal to a mixer has a frequency of 400 MHz while the other has
a frequency of 500 MHz. What is the frequency of the two output signals?
Frequency (signal 1) = 400 MHz + 500 MHz = 900 MHz
Frequency (signal 2) = 500 MHz - 400 MHz = 100 MHz
Mixers
Example
500 MHz
400 MHz
100 MHz
900 MHz
Basics Building Blocks - Mixers
Mixers
What Mixers can be used to raise OR lower the
frequency of an RF signal• Raise: upconverter and it's in a transmitter
• Lower: downconverter and it's in a receiver
Only one output signal is used The other is eliminated with a filter
Basics Building Blocks - Mixers
Mixers
Characteristics Noise figure Insertion loss called conversion loss (CL) One dB compression point Ports have designations
Basics Building Blocks - Mixers
Mixers
Port Designations
RF
LO
IF
Basics Building Blocks - Mixers
Mixers
Port Designations LO is always one of the inputs
• LO: Local Oscillator
RF/IF can be input or output• IF: Intermediate Frequency• Upconverter (transmitter): RF is output• Downconverter (receiver): RF is input
Basics Building Blocks - Mixers
Mixers
How They're Actually Used Upconverters/Downconverters
• Change the frequency
Phase modulators/demodulators• Impart or detect a phase shift
Basics Building Blocks - Mixers
Mixers
Downconverter Superheterodyne
RF Signal900 MHz
Baseband Signal64 KHzIF Signal
70 MHz
From Antenna To Demod
1. Basic Building Blocks
Transmitter/Receiver Preview
Antennas
Amplifiers
Filters
Mixers
Sources Transmitter/Receiver Review
Basics Building Blocks - Sources
Sources
Sources
Function To generate a perfect sine wave at a specified
frequency• It is the "source" of the RF• It is also called an oscillator• It feeds the LO port of a mixer
Basics Building Blocks - Sources
Sources
How Many materials produce a sine wave when
excited with electrical energy
What The objective is to produce the most perfect
sine wave possible
Basics Building Blocks - Sources
Sources
Examples
Acronym Oscillator
DRO Dielectric resonator
XO Crystal
YIG Yttrium Iron Garnet
Basics Building Blocks - Sources
Special Sources
Voltage Controlled Oscillator (VCO) The frequency of the sine wave can be made to
vary by means of an external control
Control voltage in
Sine wave out
Special Sources
Synthesizer "Sophisticated" oscillator
Frequency selector
RecapAntenna Airborne waves to current
Amplifer Makes signals bigger
Filter Elliminates unwanted frequencies
Mixer Changes a signal’s frequency
Source Produces a perfect sine wave
1. Basic Building Blocks
Transmitter/Receiver Preview
Antennas
Amplifiers
Filters
Mixers
Sources
Transmitter/Receiver Review
Transmitter Block Diagram
Transmitter Block Diagram
64 Kbps
Transmitter Block Diagram
64 KHz
Transmitter Block Diagram
64 KHz
Transmitter Block Diagram
900 MHz
70 MHz
Transmitter Block Diagram
900 MHz
Transmitter Block Diagram
900 MHz
Transmitter Block Diagram
900 MHz
Receiver Block Diagram
Receiver Block Diagram
Signals
Receiver Block Diagram
Signals
Receiver Block Diagram
Signals
Receiver Block Diagram
900 MHz
Receiver Block Diagram
64 KHz
70 MHz
Receiver Block Diagram
64 KHz
Receiver Block Diagram
64 KHz
Receiver Block Diagram
64 Kbps
Basic Building Blocks
The end
Module 2 - RF Hardware
1. Basic Building Blocks
2. Other Components
3. Circuits
2. Other Components
Switches
Attenuators
Dividers/Combiners
Couplers
Circulators/Isolators
Transformers
Detectors
Phase Shifters/Detectors
2. Other Components
SwitchesAttenuators
Dividers/Combiners
Couplers
Circulators/Isolators
Transformers
Detectors
Phase Shifters/Detectors
Other Components - Switches
Switches
Function Switch an RF signal's path
Other Components - Switches
Switches
Function Change an RF signal's path
Other Components - Switches
Switches
Where
Cell phone
Other Components - Switches
Switches
Where
Cell phone
Other Components - Switches
Switch Types
Switch Type Characterstics
Solid state FastSmall
Inexpensive
Electromechanical BigSlow
Low insertion loss
Other Components - Switches
Insertion Loss vs Isolation
Insertion Loss Loss in the closed path
Insertion loss 1 dB
Other Components - Switches
Insertion Loss vs Isolation
Isolation Loss in the open path
Isolation 30 dB
2. Other Components
Switches
Attenuators Dividers/Combiners
Couplers
Circulators/Isolators
Transformers
Detectors
Phase Shifters/Detectors
Other Components - Attenuators
Attenuators
Function To make an RF signal smaller
Heat
Other Components - Attenuators
Attenuators
Block Diagrams
Other Components - Attenuators
Attenuator Types
Attenuator Type Characterstics
Fixed Insertion loss has asingle value
Voltage Variable Insertion loss can take anyvalue over a range
Digital Insertion loss can only takecertain values over a range
Other Components - Attenuators
Digital Attenuator
Basic Building Blocks - Amplifiers
Saturated Power Suppose Psat = 40 dBm
30 dB
20 dBm
50 dBm
Recall
Other Components - Attenuators
Attenuators
Where To prevent saturation
2. Other Components
Switches
Attenuators
Dividers/Combiners Couplers
Circulators/Isolators
Transformers
Detectors
Phase Shifters/Detectors
Other Components - Dividers
Dividers
Function Break up an RF signal into 2 or more signals
Other Components - Dividers
Dividers
Function Break up an RF signal into 2 or more signals
30 dBm
1 dB
? dBm
? dBm
Other Components - Dividers
Dividers
Function Break up an RF signal into 2 or more signals
30 dBm
1 dB
26 dBm
26 dBm
Other Components - Combiners
Combiners
Function Combine 2 or more RF signals into one
2. Other Components
Switches
Attenuators
Dividers/Combiners
Couplers Circulators/Isolators
Transformers
Detectors
Phase Shifters/Detectors
Couplers
Coupler Types Also Called
Directional coupler Coupler
Bi-directional coupler Dual directional coupler
Quad coupler Quadrature couplerQuadrature (Quad) hybrid
HybridLange coupler
Other Components - Couplers
Directional Couplers
Function To "sample" an RF signal
Bi-Directional Couplers
Function To sample reflected power also
Other Components - Couplers
Quad Couplers
Function Splits a signal into 2 with a phase shift
90°
Other Components - Couplers
Quad Couplers
Where Balanced amplifier
2. Other Components
Switches
Attenuators
Dividers/Combiners
Couplers
Circulators/Isolators Transformers
Detectors
Phase Shifters/Detectors
Other Components - Circulators
Circulators
Function Reroutes RF signals
Other Components - Circulators
Circulators
Function Reroutes RF signals
Other Components - Circulators
Circulators
Function Reroutes RF signals
Other Components - Circulators
Circulators
Where
Cell phone
Other Components - Isolators
Isolators
Function To protect something from reflected power
Load
Other Components - Isolators
Isolators
Where
Base stationLoad
2. Other Components
Switches
Attenuators
Dividers/Combiners
Couplers
Circulators/Isolators
Transformers Detectors
Phase Shifters/Detectors
Other Components - Transformers
Transformers
Function Impedance matching, coupling, and others
RF outRF in
Other Components - Transformers
75 ohms 50 ohms
Impedance matching circuit
2. Other Components
Switches
Attenuators
Dividers/Combiners
Couplers
Circulators/Isolators
Transformers
Detectors Phase Shifters/Detectors
Other Components - Detectors
Detectors
Function To convert RF power to voltage
RF in Voltage out
2. Other Components
Switches
Attenuators
Dividers/Combiners
Couplers
Circulators/Isolators
Transformers
Detectors
Phase Shifters/Detectors
Other Components - Phase Shifters
Phase Shifters
Function To phase shift the output relative to the input
Input signalPhase shiftedoutput signal
Other Components - Phase Shifters
BPSK
Other Components - Phase Shifters
Phase Shifters
Where In modulators
180
Other Components - Phase Detectors
Phase Detectors
Function To convert a phase difference to a voltage
Where In demodulators
PhaseDetector
RF Input 1
RF Input 2Voltage Output
RecapSwitch Change an RF signals’ path
Antennuator Makes signals smaller
Divider/Combiner
Splits a signal evenly
Coupler Samples a signal
Quad Coupler Splits a signal with phase shift
RecapCirculator/
IsolatorReroutes a signal
Transformer Impedance matching, coupling, etc
Detector Converts an RF signal to a voltage
Phase Shifter Imparts a phase shift on a signal
PhaseDetector
Converts a phase diff to a voltage
PhaseDetector
Other Components
The end
3. Circuits
Semiconductors
Circuit Technologies
Interconnection
3. Circuits
Semiconductors
Circuit Technologies
Interconnection
Circuits - Seminconductors
Semiconductor MaterialsMaterial Comments
Silicon(Si)
Low costLow frequency
Gallium Aresenide(GaAs)
Higher costHigher frequency
Silicon Germanium(SiGe)
Low costHigh effeciency
Indium Phosphide(InP)
Highest costHighest frequency
Semiconductor Building BlocksComponent Usage
Diode Switches, AttenuatorsMixers, Detectors
Transistor Amplifers, SwitchesOscillators, Mixers
Integrated Circuit Combine multiplecomponents
Circuits - Seminconductors
Diodes
Main Structures PIN
• Power
Schottky• Speed
Circuits - Seminconductors
Diodes
Circuits - Seminconductors
Transistors
Main Structures Bipolar Junction (BJT)
• Low frequency
• High power
Field Effect (FET)• High frequency
• Low noise
Circuits - Seminconductors
Bipolar Junction Transistors
Materials Silicon
• "Bipolar"
Gallium Arsenide• Heterojunction Bipolar Transistor (HBT)
Circuits - Seminconductors
Field Effect Transistors
Materials Silicon
• MOSFET
• LDMOS
Gallium Arsenide• MESFET
• HEMT
• PHEMT
Circuits - Seminconductors
Transistors
Circuits - Seminconductors
Integrated Circuits
MMIC Microwave Monolithic Integrated Circuit
• Si, SiGe or GaAs
• Transistors + other components– Amplifiers
– Switches
– Digital attenuators
– Mixers
Circuits - Seminconductors
Integrated Circuits
RecapMaterials
Silicon - Low frequency Gallium Arsenide - Higher frequency Silicon Germanium - High efficiency Indium Phosphide - Highest frequency
Building Blocks Diodes - PIN, Schottky Transistors - BJT, FET Integrated circuits - Combination
3. Circuits
Semiconductors
Circuit Technologies
Interconnection
Circuits - Circuit Technologies
Circuit Designs
Two Types Lumped element Distributed
Dictated By Frequency
Circuits - Circuit Technologies
Circuit Designs
Lumped Element Uses discrete ("real")
passive components• Inductors
• Capacitors
• Couplers
• Transformers
Circuits - Circuit Technologies
Circuit Designs
Distributed Uses metal traces as
passive components• Inductors
• Capacitors
• Couplers
• Transformers
Circuits - Circuit Technologies
Circuit ConstructionFour Ways
Discrete Hybrid MMIC Cavity
Dictated By Cost Size Performance
Circuits - Circuit Technologies
Circuit Construction
Discrete Packaged semiconductors Lumped passives Printed circuit board
Circuits - Circuit Technologies
Circuit Construction
Hybrid Packaged or bare
chip semiconductors Lumped or
distributed passives Ceramic substrate
Circuits - Circuit Technologies
Circuit Construction
MMIC Semiconductors
devices Distributed passives On a single piece of
semiconductor
Circuits - Circuit Technologies
Circuit Construction
Cavity A hollow container Signals move as waves
inside Used for high power
Circuits - Circuit Technologies
RecapCircuit Design
Lumped - Low frequency Distributed - High frequency
Circuit Construction Discrete - High power, quick design time Hybrid - High frequency, best performance MMIC - Small size, high volume Cavity - Very high power
3. Circuits
Semiconductors
Circuit Technologies
Interconnection
Interconnection
Transmission lines
Circuits - Interconnection
Interconnection
Transmission Lines Should be 50 ohms (i.e. good match) Have insertion loss Effect system performance Can be made several different ways
Circuits - Interconnection
Transmission Lines
Can Be Made Using1) Cables - box to box
2) Waveguides - high power box to box
3) Metal traces - low power, inside a box
Circuits - Interconnection
Cables
Coaxial Cables
Inner conductor
Insulator
Outer shield
Circuits - Interconnection
Cable Assemblies
Consist Of Coaxial cable Connectors
Circuits - Interconnection
Cables
Connectors Many families
• Price
• Performance
• Evolution
Many types• Usage
dependent
Circuits - Interconnection
Cables
How To Interconnect Different Families Adapters
Circuits - Interconnection
Waveguides
What Rectangular metal
tubing
How Signals travel as
waves
Why Zero insertion loss
Circuits - Interconnection
Traces
Where On printed circuit boards
Circuits - Interconnection
Traces
Where In hybrids
Circuits - Interconnection
Traces
Where As part of MMICs
Circuits - Interconnection
TracesConstruction
Stripline Microstrip Coplanar waveguide Metal
Substrate
Circuits - Circuit Technologies
RecapTransmission Lines
Coaxial cables
Waveguide
Traces
Circuits
The end
Module 2 -RF Hardware
The end
Dinner