Transcript Ingen bildrubrik

Welcome to
gigaAnt!
Your strategic 2.4 GHz antenna
partner !
Time Table
1:30 – 2:00
Greeting
2:00 – 3:50
Technical Seminar Part I
3:50 – 4:10
Coffee Break
4:10 – 6:00
Technical Seminar Part II
This one day course contains
•Antenna definition
•Antenna parameters
•Different antenna types
•gigaAnt standard antennas
•PCB issues
•Other factors that influence the antenna
•Matching and tuning
•Testing and verification
•Range
Antenna Definition
 A device for transmitting and receiving electromagnetic
radiation
 Making a guided electromagnetic wave travel in free
space
 “A means for radiating or receiving radio waves”,
IEEE Std 145-1983
Antenna interaction
As a result, the antenna and its surrounding needs to be
regarded as a unit since they interact strongly
Electromagnetic radiation
c=f
f = 2.45GHz   = 12 cm
X-Ray, Light, Radio, Heat - It is all the same: Photons!
Influencing antenna size
material 
 Material choice
 = permitivity
 FR4  4.2 in case /2 antenna, half the length
1
r
vacuum
 Matching
Adding capacitance or inductance by means of electronic components.
 Geometry
 antenna type
 shape (helix, spiral, meander etc.)
 utilise part of the application.
Frequency bands for Mobile phones
NMT
EAMPS
GSM
EGSM
NTT
DCS
PCS
UMTS
ISM
MHz
450 and 900
824-894
890-960
880-960
870-925
1710-1880
1850-1990
1920-2170
2400-2483
Visible light
THz
ISM = Instrumentation, Scientific, Medical
Bluetooth
WLAN (IEEE 802.11)
HomeRF
40 Countries
USA
Europe
Europe
Japan
Europe
USA
Worldwide
Frequency bands for data communication
WLAN
902-928 MHz
2.4-2.483 GHz
5.15-5.35 GHz
5.725-5.875 GHz
On the way out
Available
Available soon
Will perhaps be available
BT
2.4-2.483 GHz
5.15-5.35 GHz
Available
Available soon
GPS
1575,42 MHz
Available
Antenna parameters
Knowledge about the antenna parameters is needed in order for us to
understand our customers and vice versa.
•Lobes
•Frequency Band
•Gain
•Radiation pattern
•Polarisation
•Efficiency
Radiation pattern
3D Radiation pattern with lobes
Linear plot of power pattern
Radiation intensity
 Radiation intensity in a given direction, U  ,   , is defined as
the power radiated from an antenna per unit solid angle
 Radiation intensity for an isotropic source:
Prad
, [W/unit solid angle]
4
is the total power radiated by the source
U isotropic 
 where Prad
Directivity
 Directivity is a measure of how an antenna concentrates the
radiated power in a particular direction.
 Directivity is the ratio of the intensity, in a given direction, to the
radiation intensity that would be obtained if all the power radiated
by the antenna were radiated isotropically:
U ( ,  )
D( ,  ) 
U isotropic
Prad
 a unitless figure
4U ( ,  )

Prad
Gain
 Gain is a measure of how an antenna concentrates the radiated
power in a particular direction.
 Gain is the ratio of the intensity, in a given direction, to the
radiation intensity that would be obtained if all the power was
accepted by the antenna and was radiated isotropically:
U ( ,  )
G ( ,  ) 
U isotropic
PTot
 a unitless figure dBi
4U ( ,  )

PTot
Gain/Directivity
• Isotropic
• Omnidirectional
• Lobes
• Dipole = Donut
• Normally measured in dB
• Relative unit
• dBi: relative ideal isotropic
• Isotropic radiator has 0dBi gain
• dBd: relative ideal dipole (1 dBd 
2.14 dBi)
• If a gain value is given without any
direction, it is the maximum gain
More power in one direction at the expense of other directions
Gain: good/bad
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Stationary or mobile application
Important to reach out in a certain direction
Wall or corner position
Less important inside a small room due to
reflections
 Regulation limits
ETSI EN300328 Max 100mW eirp
FCC 15.247 peak power reduction when
antenna gain over 6dBi
Decibel
•Used to compare two figures
with each other
•Describes better
measurable steps than
fractions
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dB
dBi (isotropic)
dBd (dipole)
dBm (miliwatt)
dBw (Watt)
•Always unitless
a
valuedB  10Log10  
b
Antenna efficiency (total)
 Good figure of merit, especially for small antennas
 Ratio of the power sent to the antenna to the power radiated by
the antenna
 Unitless
R
 Ideal 1
 Often given in percent
Tot
P

P
 Radiated efficiency is given as the ratio of the power accepted by
the antenna to the power radiated by the antenna, and is thus
higher than totoal efficiency if there is losses in strip line,
components etc.
 The average gain in all directions is the same as the efficiency.
Polarization
• Circular
• Linear
• Small antennas have no
clear polarization
• Reflection affects
polarization
Maximum power transfer requires polarization match between antennas
in free space. In reality, polarization is not a problem.
EVOLUTION 1.
Monopole
L- antenna
/4 - Pin
/4 - Pin
Good, but
very tall, 37
Ohm
Better, medium
tall, but
capacitivity to
earth plane
F- antenna
PIFA
(Wire inverted F-antenna)
(Planar inverted F-antenna)
Move feeding
point to 50 Ohm
to create high
inductance.
High surface
current = high
power loss
Create larger
area to minimise
surface
resistance and
power losses
EVOLUTION 2.
/2 - PATCH
Large
In the middle of the antenna
the Voltage = O v.
/4 - PATCH = PIFA
That point is connected to
earth and the antenna size is
reduced by half.
Microstrip
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Printed on PCB
Low cost
Although thin, quite large
Depends on variation in board material
Free space-dependent
Narrow bandwidth
Your strategic partner !
Complete antenna solutions
Application
know-how & tuning
Proven
concepts
Antenna
delivery
Verification of antenna
performance
Your Benefit
• Shorter time to market
• Project support from A to Z
• High performance solutions
2.4 GHz antenna concepts
for a wide range of applications
Head sets
Laptop
Snap-in
ICM
Mobile phones
Instruments
SMD
Digital pens
Dongles
SWIVEL
PCMCIA-cards
PDA’s
External Concepts
Swivel
TITANIS
Gain
Efficiency:
VSWR
Length :
1.6 dBi
75%
<1.5:1
50 mm
Basic data
External 1/2 wave dipole Independent of ground plane with
internal matching net
Typical Applications
Development kits, Prototypes, Printers , Instruments
VIRAGO
Gain
Efficiency:
VSWR
Length :
1.6 dB
75%
<1.5:1
50 mm
Customer benefits
- Easy implementation - no matching & tuning
- Perfect for feasibility studies
- High performance - reliable data transfer
- Designed for flexible mounting - rotating antenna blade
Internal concepts
Snap-in
FLAVUS
Gain
VSWR
Efficiency:
Dim (mm) :
1.4 dBi
<1.4:1
62 %
8x27x3 mm
General
Internal 1/2 wave dipole independent of
ground plane with external matching
Applications
Mobile & desktop computers, Measuring instruments
audio equipment, Automotive systems, Note books
CRISPUS
Gain
VSWR
Efficiency:
Dim (mm) :
1.6 dBi
<1.5:1
73%
20x30x4
Customer Benefits
- Easy & fast implementation - 1 working week
- High performance - reliable data transfer
- No soldering
- Designed for pick & place
- Proven concept
ICM concept
ICM - Single band
General
Internal Case Mounted antenna 1/2 wave dipole
independent of ground plane with external matching,
customized design of contact points and antenna.
ICM - Multi Band
ICM - Dual band
Applications
PDA’s, handheld devices, instruments, etc
Customer benefit
- High performance where space is restricted
- Flexible mounting - type of fastening
- Fast implementation compared to ceramic
- Requires little space - only contact pad
- Multi purpose antennas - 2.4 GHz & GSM
SMD concept
MICA
Gain
VSWR
Efficiency:
Dim (mm) :
General
Internal 1/4 wave PIFA dependent of ground plane.
3-5 dBi
<2.5
60%
19x3.2x3.2
Applications
Mobile & desktop computers, Measuring instruments
audio equipment, Automotive systems, Note books
Customer benefits
- Easy and fast implementation - 1 week
- Designed for SMD soldering
- High performance - reliable data transfer
- Small in size
- Less sensitive than ceramic
CUSTOMER
Antenna
selection
Footprints
Appli.notes
samples
Review of
design
& PCB
STARTUP
Design of
prototype
Prototype
ready
PROJECT
Ramp-up
PRODUCTION
gigaAnt
Antenna
selection
guidance
Review of
PCB design
Tuning &
Matching
Verification
of prototype
Final
report
Antenna
delivery
ICM
Design of Transmission
Antenna
Tuning in
mechanical
Line
specification
prototype
Interface dimensioning
SMD
Snap-In
Swivel
Virago
Verification Ramp-up Antenna
of prototype production delivery
Review
of
PCB design
Transmission
Line
dimensioning
Review
of
PCB design
Transmission
Matching Verification
Line
in prototype of prototype
dimensioning
Antenna
delivery
Review
of
PCB design
Transmission
Line
dimensioning
Antenna
delivery
Tuning in Verification
prototype of prototype
Custom.
Tooling
Antenna
delivery
Swivel
Titanis
Antenna
delivery
Implementation issues
 Internal / External
 Standard or custom made
Time schedule, estimated production volume, Available volume in device
 In-House or RF-Partner with know-how
 Required performance
 Space limitations
 Operating environment
 Continuous dialog
 Understanding for RF-problems
 Early access to chassis
 Early access to populated PCB
Antenna implementation: Standard concept
Advantages
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Well known electrical performance
Environmentally / mechanically tested
Specifications and application note available
Tools already manufactured
Fast implementation
Lower price
Possible solution for low volume applications
Disadvantages
 Hard to fulfill special requirements
 Size/Shape might not fit available volume optimal (form factor)
Antenna implementation: Standard concept
Common steps (RF point of view)
 Advice customer in antenna choices and placement
Performance, Available volume, Hands…
 Review PCB-drawing for RF-mistakes
Feeding (length, path, dimensions), Matching location, Ground
plane, Through plating, Calculations…
 Build mock-up
Antenna performance, Matching, Covers, Surrounding
components, Hidden things…
 Final product
Matching, Tuning, Measurements
 Report
Antenna performance, Matching
 Follow up
Antenna implementation: New concept
Advantages
 Meet special requirements
 Use all available volume in order to increase antenna
performance
 Chance to start a new standard concept
Disadvantages
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Uncertain antenna performance
No documentation available
Always a risk in new tools
Uses lot of resources and time in organization
Might only fit one application
Costly in small volumes
Antenna implementation: New concept
Common steps (RF point of view)
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Advice customer in antenna choices
Build mock-up, often several in a developing process
Check PCB for RF-mistakes
Find subcontractor for tools, material, manufacturing
Test products from subcontractors
Order tools (prototype tool, soft tool, hard tool)
Environmental test on parts from tools
Changing tools
After receiving PCB, matching and measurement
Changes in PCB and covers are common
Several reports during the process
Follow up
Ceramic Antennas
Pros
Cons
 Small size
 Compact surface mount units
 Large ground plane
dependence -> high of nonworking antenna
 Narrow bandwidth
 Low efficiency
 Hand sensitive
Mechanical design
Parameters that affect performance
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Covers: Material, Shape, Colors, Metalisation
Free space / Office environment
Humans
Stationary/mobile application
Reflections from walls etc
Environmental factors
Electrical design
Parameters that affect performance
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Ground plane
Position
Surrounding components
Transmission line dimensions
Feeding (balanced/unbalanced)
Matching
Through platings
Strips
Even if calculated to be 50 ohm, if too thin it introduces large
losses due to distributed parasitic coupling to ground plane.
Long strips should be avoided because of the high losses at
2.4 GHz in general FR-4.
Sharp bend should be avoided because of the parasitic
effects. Better to split up into two bends or a large radius.
Some effects could be avoided if corner is chamfered.
Different type of strip lines
Microstrip
Stripline
Co-planar waveguide
Grounded coplanar waveguide
Antenna impact on the PCB
• Antenna require certan ground plane
• Or lack of ground plane
• Be aware of antenna user interaction
• RF close to radio chip because of feeding
• Area for matcing components
• Surrounding components (battery, contacts, cables, loudspeaker)
• Outside shielded areas
Transmitter characteristics
Receiver characteristics
0dBm TX Power
-40 dBm RX Power @ 1m
Specification requires -70dBm
Some radio chips down to -90dBm
-70 dBm RX Power @ 10m
-90 dBm noise floor
The actual sensitivity level is defined as the input
level for which a raw bit error rate (BER) of 0.1% is
met. The requirement for a Bluetooth receiver is an
actual sensitivity level of –70 dBm or better. The
receiver must achieve the –70 dBm sensitivity level
with any Bluetooth transmitter compliant to the
transmitter specification
The 10 meter range is not included in Bluetooth specification.
Antenna range
Operating
distance , n = 2.3
16
14
12
10
8
-5
Friis transmission equation
relates operating range,
power and gain
Hard partition office
decreases range 
increases n
-4
-3
-2
-1
loss
Two antennas with 2 dBi gain
Radio fulfilling -70 dBm.
in dB
Antenna measurements
Network Analyser
 Measuring S-parameters in frequency domain
VSWR, Return Loss, Smith Chart
 Phase
 Evaluate matching
 Evaluate undesired losses
 Coverage measurements
VSWR
(Voltage Standing Wave Ratio)
• Determination of matching
between the antenna and the
transceiver in the prototype
• Essential to minimising power
losses
VSWR
• Ideal 1:1
• Typical 2:1
• Minimized by
matching network
Power sent to the antenna should be accepted and not reflected.
Return Loss
• Used to describe antenna
• Related to VSWR
• Narrow / Spread band
•S11-parameter
RL  10log10
Pinput
Preflected
 VSWR  1 
RL  10log10 

 VSWR  1 
2
The analyzer sweeps frequencies and register reflection from antenna
Smith Chart
• Based on the result of
Smith Chart measurements
gigaAnt can carry out
network matching
• Antenna Impedance
•Strip line impedance
Smith Chart is used for matchinng and adjusting antennas
Transmission measurement
• Losses in feeding
• Losses in connections
• Isolation between antennas
• S12-parameter
Antenna measurements
3D radiation pattern
• Radiation pattern of the antenna
when mounted in the actual
device
• Needed to ensure the required
functionality. It is easily seen if an
antenna really is sufficiently
omnidirectional or if a directional
antenna has the expected
radiation pattern.
Field regions of antenna
3D radiation pattern measurement
•Anechoic chamber with
shielding and absorbers
•Advanced controlling of probe
position
•Two probes collecting both
polarisations
•Network analyzer to collect data
•Nearfileld to farfield
transformation
•Measure one frequency at the
time
•DUT is rotating phi while probes
are stepping theta.
Radiation Pattern
Pattern from Bluetooth
swivel under development
measured in Moteco´s
anechoic chamber.
A 3D scan reveals things a
2D scan never could.
Antenna measurements
SAR - (Specific Absorption Rate)
Governmental/ International agreement
on how much a transmitting unit is
allowed to heat tissue
We verify compliance with
national/international regulations
E 2
SAR 

 = Tissue conductivity (S/m)
E = Electric field strength in tissue (V/m)
 = Tissue dencity (kg/m3)
SAR
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Not necessary for the 10 meter (1dBm) Bluetooth standard
Necessary for the 100 (20dBm) meter Bluetooth standard
Europe 2.0 mW/g over 10g cube tissue
USA 1.6 mW/g over 1 g cube tissue
 SAR measurements are difficult
 Requires expensive and advanced equipment
Field measurement
•Examination of the electrical
and magnetic fields on the
surface of the product
(prototype) and antenna
•Important measurements the
result is used during the
development process to verify
functionality and to ensure SAR
compliance
Summary Antenna Development
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Simulation is a useful tool, but not perfect
The PCB is very essential to make a good antenna.
Prototypes are an essential part of the development
Continuous measurement and verification after changes in
the surroundings
 Experience and know-how are important for a good result
 Iteration between design and measurement is needed
You need the right
antenna to
communicate !
What ?