Antennas: the key to your wireless application Harald Naumann Round Solutions
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Transcript of Antennas: the key to your wireless application Harald Naumann Round Solutions
www.roundsolutions.com 2 / Harald Naumann / 07.04.2009© Round Solutions GmbH & Co. KG
Dipole or monopole?Dipole or monopole?
Monopole with "mirror" on ground plane
Dipole shows that antenna has two rods
To transmitter(GSM module)
half wave length
www.roundsolutions.com 3 / Harald Naumann / 07.04.2009© Round Solutions GmbH & Co. KG
Benefits of embedded monopolesBenefits of embedded monopoles
Small size
Size interferred by of half wave length only
Assembling direct on PCB
Cost savings by automatic pick and place
Cost savings, because no costs for coaxial cables needed by using of micro strip lines
Higher reliability by bypassing coaxial connectors
Q: When to select a monopole? A: If small size is needed, integration inside the enclosure
or just for cost reduction.
www.roundsolutions.com 4 / Harald Naumann / 07.04.2009© Round Solutions GmbH & Co. KG
Drawbacks of embedded monopolesDrawbacks of embedded monopoles
Reasonable ground plane of 3500 to 4500 mm in square needed
Components in the near will interfere and detune the antenna
Even Epsilon R of plastic enclosure will have an impact on centre frequency
Antenna could interfere with micro controller, power supply or any other component on PCB
Q: How to minimize the risk on embedded monopoles? A: Select a partner that will help with modules, antennas,
references and GSM testers for final design check.
www.roundsolutions.com 5 / Harald Naumann / 07.04.2009© Round Solutions GmbH & Co. KG
Practical use of interferencePractical use of interference
A good example for radio waves and interference is the musical instrument Theremin.
The Theremin creates sound by changing the position of your hands in the electromagnetic field
In same style components in the near will interfere and detune your antenna
Q: How to tune the embedded monopole antenna? A: There are several options. Please take care and follow the
guideline on free space, distance to ground and place formatching circuit. Please show steps in between to yourantenna partner and ask for their advice.
www.roundsolutions.com 6 / Harald Naumann / 07.04.2009© Round Solutions GmbH & Co. KG
Examples for embedded monopoles Examples for embedded monopoles
Q: Which antenna to select? A: This depends on cellular bands to by covered and ground
plane you can offer.
Tri band GSM
Dimensionsin mm:20.5 x 7 x 3.2
Antenna GXE477
Quad band GSM + UMTS 2100
Dimensionin mm:24 x 4.4 x 5.6
Antenna GXE472
Tri band GSM
Dimensionsin mm:30 x 6 x 5
Antenna GXE475
www.roundsolutions.com 7 / Harald Naumann / 07.04.2009© Round Solutions GmbH & Co. KG
Voltage Standing Wave Ratio VSWR Voltage Standing Wave Ratio VSWR
Practical not possible
Nothing will be reflected
VSWR =1
Already not that nice
A lot of energy is not feed to the antenna
VSWR = 3
Q: Why VSWR is important? A: Any energy that is not feed to antenna never has a chance
to be radiated.
Reasonable practical value
Part of wavewill be reflected
VSWR = 2
www.roundsolutions.com 8 / Harald Naumann / 07.04.2009© Round Solutions GmbH & Co. KG
Antenna EfficiencyAntenna Efficiency
The efficiency of an antenna relates the power delivered to it and the power radiated or dissipated within the antenna.
A high efficiency antenna has most of the power present at the antenna's input radiated away.
A low efficiency antenna has most of the power absorbed as losses within the antenna.
Q: Why and when antennaefficiency is important?
A: If efficiency is low, thenpower consumption ishigher. The stand by timeof your product will be
less.
You will spend more money
for bigger batteries.
The products of competition
with better antennas will work at locations, whereyour product has already
topass.
input
radiated
www.roundsolutions.com 9 / Harald Naumann / 07.04.2009© Round Solutions GmbH & Co. KG
Impact of a reduced ground plane Impact of a reduced ground plane
DUT antenna ANT-GXE477
Lenght of ground plane
Good VSWR on GSM 900 and GSM 1800 MHz band
Optimised ground plane
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Impact of 15 cm smaller ground plane Impact of 15 cm smaller ground plane
DUT antenna ANT-GXE477
Lenght of ground plane cut by 15 cm
Centre frequency on GSM 900 and GSM 1800 MHz band still ok
VSWR on GSM 900 is already less
VSWR on GSM 1800 has not changed
Optimised ground plane
Q: Why is there no change on GSM 1800?
A: Because wave length is only the half.
www.roundsolutions.com 11 / Harald Naumann / 07.04.2009© Round Solutions GmbH & Co. KG
Impact of 30 cm smaller ground plane Impact of 30 cm smaller ground plane
DUT antenna ANT-GXE477
Lenght of ground plane cut by 30 cm
Centre frequency on GSM 900 and GSM 1800 MHz band still ok
VSWR on GSM 900 is already poor
VSWR on GSM 1800 is still close the same
Optimised ground plane
Q: Do you know options on optimization?
A: Yes, often we can help with hints and tipps.
www.roundsolutions.com 12 / Harald Naumann / 07.04.2009© Round Solutions GmbH & Co. KG
Ground plane in praxisGround plane in praxis
Q: Why does my GSM antenna radiates, but my GPS antennadoes not work?
A: Why didn’t your supplier sell you a starter kit;why didn’t they recommend to take care on ground
plane?
Please do not follow the upper example Please do not follow the upper example
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Do's and Dont's during development Do's and Dont's during development
Never place ground plane or tracks underneath the antenna Never place the antenna very close to metallic objects Be careful about the wiring in the finalized product, not too
close to the antenna A monopole antenna should have a reasonable ground plane to
be efficient Do the final tuning in the end product, not in free air Never install a chip antenna in a vastly different layout than the
reference design, and expect it to work without tuning Do not use a metallic enclosure or metallized plastic for the
antenna Test the plastic casing for high RF losses, preferably before
production Never do a cut and paste antenna design and expect it to work
without testing Do not use very thin PCB tracks, the tracks should be fairly
wide
www.roundsolutions.com 14 / Harald Naumann / 07.04.2009© Round Solutions GmbH & Co. KG
International success storiesInternational success stories
Medical Intelligence,Canada
Eureka,Italy for
e-foxx,Germany bplan,
Germany
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Customised external antennasCustomised external antennas
Q: Can you help us with antennas that will pass PTCRB? A: Yes, we can help with standard and customised antennas.
GSM 850/1900 antenna GSM 850/1900 antenna with American PTCRB with American PTCRB approvelapprovel
Narrow band GSM-RNarrow band GSM-R antenna on top of antenna on top of information terminalinformation terminal
Top and back viewTop and back view of GSM-R antenna of GSM-R antenna
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Embedded antenna GSM 900/1800 Embedded antenna GSM 900/1800 and ISM 868 for electricity meterand ISM 868 for electricity meter
Result after customisation:The VSWR for GSM 900 is always better than 1.9 and in GSM 1800 MHz band the VSWR is always better than 1.6.
Before After
www.roundsolutions.com 17 / Harald Naumann / 07.04.2009© Round Solutions GmbH & Co. KG
Enhanced servicesEnhanced servicesDesign in aid for embedded antennas Design in aid for embedded antennas Tuning and
customisationof antennas
Developmentof matchingcircuit
Development of new customisedantennas
Mount standard part on board and check for shift in characteristics Select an item from the frequency and impedance series to correct
the shift in characteristics Mount the new part on the board and check characteristics
Repeat steps 2 and 3 if necessary to get the best results
Receipt of Customers Board
Measure the radiation pattern in the company's anechoic chamberCheck the center frequency, upper and lower band limits as well asverify the gain.
Send a technical report of the test results and a recommendation for the part to use to the customer.
CustomerCustomer
TuningTuning
Standard MeasurementsStandard Measurements
Make Technical ReportMake Technical Report
CustomerCustomer
www.roundsolutions.com 18 / Harald Naumann / 07.04.2009© Round Solutions GmbH & Co. KG
Q: How to find the best partner?
A: Just divide the number of listed components on line cardby support engineers
Where to buy my antennas?Where to buy my antennas?
Wireless Solution supplier
300 components
You get all parts you need and it fits always together
Best support, becausethe team has to serve minimum lines
Special distributor
3000 components
You get a fewmore parts
Good support, because the team has to serve a few lines
Broadline distributor
30000 components
You get a few parts for your project
Poor support, becausethe team has to serve several lines
www.roundsolutions.com 19 / Harald Naumann / 07.04.2009© Round Solutions GmbH & Co. KG
Do not burn your moneyDo not burn your money
Be careful when selecting your antenna supplier
First plane the size of PCB and antenna
Doing the other way around can force enormous costs
Better spending money for feasibility study, then loosing the chance to get GSM operator approval
Take care that GSM operators like Cingular and Vodafone are looking for antenna efficiency of at least of 40%
Our European wireless paradise will shrink, as soon operators will use close the same rules than the Americans
Hire resources as soon you run in trouble with your RF design
The best RF amplifier is a good antenna
The best antenna you get by selecting a high position
www.roundsolutions.com 20 / Harald Naumann / 07.04.2009© Round Solutions GmbH & Co. KG
Tools and services to play with Tools and services to play with
Q: Where to get all thetools and services?
A: Please feel free to askfor measurement equip-ment, consulting,
studies and development with us.
Please note that we offer the loaning of GSM testers and other equip-ment for premium customers free of charge.
www.roundsolutions.com 21 / Harald Naumann / 07.04.2009© Round Solutions GmbH & Co. KG
Why not to use services like Why not to use services like rapid prototyping of enclosures?rapid prototyping of enclosures?
Robust material Polyamide
Very detailed by usingfiles in format STL
Minimum edge lengthof polygons 0,01 mm
Only Euro 350 to 400for handheld enclosure
Delivery after 2 - 3 workingdays
Final enclosure
Prototype
www.roundsolutions.com 22 / Harald Naumann / 07.04.2009© Round Solutions GmbH & Co. KG
Why not being a part of a huge Why not being a part of a huge community?community? World's biggest forum for wireless
applications
5.000+ members
Support and information24 hours/7 days a week
www.roundsolutions.com 23 / Harald Naumann / 07.04.2009© Round Solutions GmbH & Co. KG
Round Solutions GmbH & Co. KGHans-Boeckler-Straße 1663263 Neu-Isenburg, Germany
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Thank you for listening.More about antennas and services around at stand A17
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