© 2005, it - instituto de telecomunicações. Todos os direitos reservados.
Car Antennas
Luis Brás, Nuno Carvalho,
Pedro Pinho
Instituto de Telecomunicações - Aveiro, Portugal
2
Outline
• Introduction
• Car antennas
• Transparent Conductors
• Transparent Antennas
• Conclusions
3
Services of today
• GSM/UMTS
• Elect. Toll Collec. (ETC)
• Satelitte Radio
• DVB-S
• Tire Pressure... (TPMS)
• Remote Key Entry (RKE)
• ...
4
AM-Radio
0.5 – 1.7 MHz
FM-Radio
78 – 108 MHz
RKE/TPMS
315 – 433 MHz
TV
470 – 880 MHz
GSM
824 - 960 MHz
L1/L2-GPS
1227/1575 MHz
GSM
1710 - 1990 MHz
WiFi/Bluetooth
2400 - 2500 MHz
Satellite TV
12200 - 12700 MHz
Radar Collision
Detection System
22000 – 26000 MHz
76000 – 77000 MHz
ETC
5800 MHz
V2V V2I
5900 MHz
Frequency (MHz)
Frequency Spectrum
5
Car Antenna requirements
• System requirements (RP, BW, polarization)
• Vehicular requirements
• Aesthetics
• Manufacturability
• Weather resistance
• Weight/Cost
• Vandalism
• Damage resistance
(car wash, tree branches,...)
6
Outline
• Introduction
• Car antennas
• Transparent Conductors
• Transparent Antennas
• Conclusions
7
1
Car Antennas (1)
AM/FM (helical antenna)
GPS/cellular design
(Patch/IFA/Slot Antenna) 5
6 2 3 4
7
8
8
Car Antennas (2)
Satellite TV Antenna
(Phased Array)
1
5
6 2 3 4
7
8
9
Car Antennas (3)
AM/FM
DAB
Traffic Msg. Control (TMC)
(Mendered Microstrip)
1
5
6 2 3 4
7
8
10
Car Antennas (4)
ETC (BendMonopole/IFA)
Cellular (Dual Band Microstrip)
GPS (CP Patch)
1
5
6 2 3 4
7
8
11
Car Antennas (5)
1
5
6 2 3 4
7
8
AM/FM
DAB
TV
GPS
(Mendered Microstrip)
12
Car Antennas (6)
Automotive Radar Antenna
(Microstrip Antenna Array)
1
5
6 2 3 4
7
8
13
Car Antennas (7)
Tire Pressure Monitoring
Systems (TPMS)
(Microstrip mendered)
1
5
6 2 3 4
7
8
14
Car Antennas (8)
Remote Start engine (RSE)
Remote Keyless entry (RKE)
(loop, bend & mendered
Monopole)
1
5
6 2 3 4
7
8
15
Omnidirectional Microstrip Array
-30
-30
-20
-20
-10
-10
0 dB
0 dB
90o
60o
30o
0o
-30o
-60o
-90o
-120o
-150o
180o
150o
120o
Measured
Simulated
Implemented Antenna for DSRC
16
We defined new requirements
Transparent Antenna
Beamforming Networks
Array • Higher Gain
• Beam Control
• Reduced Impact
to the driver view
System integration
Directive transparent Antennas
Beamforming network
17
Outline
• Introduction
• Car antennas
• Transparent Conductors
• Transparent Antennas
• Conclusions
18
Transparent Conductors
Transparent
Conductor
Characteristic
Indium Tin
Oxide (ITO)
Most commonly used, durable, chemical resistance
to moisture, can be precisely etched
Indium Zinc Oxide
(IZO)
Is used quite often in the LCD’s, easily etchable,
but not as durable as ITO
Zinc Oxide with
Aluminum (AZO)
Lower cost and relatively good optical transmission,
lower chemical resistance to moisture
Fluorine doped Tin
Oxide (FTO)
Difficult to etch fine patterns has made its use
primarily for plasma displays
19
Transparent Conductors (common application)
Advantages Low production cost
High resistance to dust and water
Best used with a finger, gloved or stylus
Best suited for handwriting recognition
Disadvantages Not too sensitive
Poor contrast
Does not support multi-touch
Advantages Looks brighter and sharper
Highly touch sensitivity
Supports multi-touch
Disadvantages Not working with simple gloves
More expensive
Glass is more prone to breaking
20
Outline
• Introduction
• Car antennas
• Transparent Conductors
• Transparent Antennas
• Conclusions
21
Transparent Antennas
Conductive films can be used for antennas, however with poor
radio frequency performance...
ALTERNATIVE?
Grid antennas...
22
Grid Antennas (1)
Reference Antenna
Space between metal strips
(100 um, 200 um, 300 um)
23
Grid Antennas (2)
Space between metal strips
(100 um, 200 um, 300 um)
Reference Antenna
24
Conclusions
• Transparent antennas can be a solution for car antennas
• ITO based antennas can be a solution, however with
poor RF performance
• Grid antennas are a valid alternative
• Transparency is inversely proportional to antenna
efficiency
25
Thanks for your attention…
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