Funke 4G LTE INERT Technology Prominent DTT Antenna Qualities
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October 2013
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Introduction
DTT receiving antennas come in many forms, brands and prices.
Great variety in pricing – or better – performance over price.
Quality of Rx (Receiving) antenna becomes more prominent in nowadays
DTT networks as there is more demand for wireless communication in all
kind of forms (mobile services, wireless LAN, fixed links, PMR*, PMSE*).
This presentation summarizes the most prominent qualities of a good
antenna that will perform in today’s and tomorrow’s DTT network.
* PMR = Public Mobile Radio, PMSE = Programme Making and Special Events
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Prominent Antenna Qualities
There are many qualities to an antenna. Only a few are really
prominent in system performance.
<< prominent antenna parameters
Shown Scenarios:
[A] Rural areas – far away from transmitter(s)
[B] (Very) Close to transmitter
[C] Urban areas – buildings, large infrastructural objects, ...
[D] Under influence of disturbances (e.g. 4G / LTE or GSM)
[E] Rural/Mountainous areas
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Low Noise
EVERY antenna adds noise to the system:
(passive : 4kTR (Noise Temperature)
(active : depends on LNA design (1 .. 5 [dB]))
Low noise floor achieved by sound LNA* design
(topology, PCB design, selection of components,..)
In particular relevant for reception far away from Tx (transmitter)
and in urban area’s (w/ many disturbances) to offload demands on
STB.
* LNA = Low Noise Amplifier (in Antenna)
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High IP3 (3rd Order Intercept)
Only applicable for active antennas.
High IP3 achieved by sound LNA design
(topology and selection of components,..).
In particular relevant for areas where there are (relatively) high
power disturbances (GSM, LTE, ...) in adjacent bands in spectrum.
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Antenna Gain
Distinguish active from passive gain:
(Total) Antenna gain = Passive Gain + Active Gain
Passive gain contributes to a good C/N (carrier over noise), active
gain does not.
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F/B Ratio and Antenna Diagram
F/B (Front-to-Back Ratio) comes with the antenna concept and
implementation.
Trade-off between usability and 4G LTE/GSM protection:
too small Ѳ : re-orientating antenna (after house cleaning
e.g.) may cause loss of signal strength...
too big Ѳ : end-user not able to ‘turn away’ from
disturbances...
Funke promotes to use STB with option to display BER/MER* or
signal quality indicator to allow user to position antenna for best
reception.
Ѳ is opening angle (-3[dB]), * BER/MER = Bitrate /Modulation Error Rate
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F/B Ratio and Antenna Diagram
Example of a modest F/B (e.g. DSC550):
ѲH,3dB @ 506 MHz = 130°
ѲH,3dB @ 578 MHz = 90°
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F/B Ratio and Antenna Diagram
End-User Self Help Model by Funke:
- End-User should not need to have upfront info on the
whereabouts of all transmitters or disturbances in order
to setup the antenna at home.
- Use the BER/MER/Signal Quality Indicator (STB) to position
and orientate DTT antenna.
- Simple, yet efficient: - LED for 5VDC power supply
- Postcode Check
- Online Q&A / Instructions / …
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F/B Ratio and Antenna Diagram
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F/B Ratio and Antenna Diagram
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F/B Ratio and Antenna Diagram
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F/B Ratio and Antenna Diagram
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Funke 4G LTE INERT Technology
Relevance of filtering becomes more relevant now spectrum
becomes over-crowded, often with (very close by) adjacents with
relatively high power, like 4G LTE, GSM...
Since ‘neighbors’ are very close by (in frequency), steepness of
gain curve must be high and fall-off frequency reproducible (in
mass production).
As explicit Funke IP, our compact PCB implementation is very well
suitable to full fill these requirements.
Can be adapted – by design - for future LTE requirements (e.g. 700
[MHz])
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Standard DTT transmission
LPF = Low Pass Filter
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4G LTE signal distortion
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Funke 4G LTE INERT Technology
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Funke Product Range