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Antenna calibration/tuning in smartphones

 
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Moridin
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Joined: 13 Sep 2014
Posts: 3

PostPosted: Sat Sep 13, 2014 8:57 pm    Post subject: Antenna calibration/tuning in smartphones Reply with quote

Hi,

I'm currently working on an article based on my own experiences based on an iPhone. I have a European model and when used in other countries and on other networks, it exhibits increased or decreased battery life. Example:

Poland: phone is cool, good reception, 8-10 hours of battery life
Italy: as above, 10-12 hours of battery life despite roaming
India: phone gets hot, 3-4 hours of battery life
USA: phone gets hot from time to time, 5-6 hours of battery life

My theory is that manufacturers calibrate/tune (what's the technical term?) antennas differently for various continents and in different phone models, hence the different behavior.

Could you please point me to where I could find more information on the subject?
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la7no
Antenna Theory Regular


Joined: 05 Jul 2014
Posts: 22
Location: Bergen, Norway

PostPosted: Sun Sep 14, 2014 2:01 pm    Post subject: Reply with quote

Hello,

But these observations are with the same iPhone. Or?
So it is the same antenna and calibration in all cases.
Or are you referring to the different GSM cells?

Myself, I have never noticed such differences between countries.

P-T
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Moridin
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PostPosted: Sun Sep 14, 2014 2:13 pm    Post subject: Reply with quote

Same phone. I've observed this on others too though, eg. HTC One to name one example.
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la7no
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Location: Bergen, Norway

PostPosted: Sun Sep 14, 2014 2:18 pm    Post subject: Reply with quote

OK.
But how can it be a matter of different antenna adjustments if it is with the same phone?

P-T
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Moridin
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PostPosted: Sun Sep 14, 2014 5:38 pm    Post subject: Reply with quote

My apologies, let me explain:

Smartphone manufacturers offer various versions of their phones depending on which country/continenet that they're being sold on.

Example:

A US iPhone will work properly in USA/Canada/etc and get 8-10 hours of battery life. In Europe or Asia it will exhibit increased temperatures and shorter battery life (eg. 6-8 hours). A US iPhone supports different bands and has different antennas.

An EU iPhone will of course be the other way around, as first detailed in my earlier posts.

Do you know if various chipsets + different antennas can account for the need to increase the signal strength of the antenna and hence generate more heat and result in shorter battery life?
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la7no
Antenna Theory Regular


Joined: 05 Jul 2014
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Location: Bergen, Norway

PostPosted: Sun Sep 14, 2014 5:55 pm    Post subject: Reply with quote

Thanks for the clarification.

For a mobile phone (in particular for one with support for multiple bands), the antenna will of course have to be a big compromise.

I would have expected a US and EU phone to behave similarly on the same band. But, you might have a point. The antennas can very well be optimized for different bands.

Sorry, I have no info on the different chipsets.
But I'm sure other people on this list could help.

P-T
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E Kafeman
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Joined: 04 Feb 2013
Posts: 25
Location: Sweden

PostPosted: Mon Sep 15, 2014 4:34 am    Post subject: Reply with quote

It can be a numerous reasons that affects power consumption.
For any cellular phone, if network coverage is less good must phone use more TX power to keep in contact with base-station.
Depending on phone model, if it is a Iphone4, that phone model have some specific antenna problems (search antennagate). Its antenna have problems that is depending on how the phone is held. It is not so visible in number of signal-bars as one of the fixes to solve problem was to by software adjust scaling of the bars. Another fix was to add a rubber bumper around phone as it then reduced hand-effect which else could cause antenna degradation.
This problem is worst for very specific parts of the frequency band, so depending on which cellular plan you have, say AT&T or T-Mobile or O2 can it result in a bit different battery consumption as they are active in different parts of same GSM band.

Most modern smart-phones are a bit too thin, with a display that is further reducing available internal height, so it is not possible to make well performing embedded antenna, especially for the lowest frequencies.

Unfortunately, these lowest frequencies are mainly used outside of cities, where also less good cellular coverage are more likely.
Less good antenna in combination with less good coverage results in that phone must use max TX power to not drop calls or update its registration with local base-station.. It results in that battery is drained much faster then when same phone is in areas with good coverage.

If it is a Iphone4, there can be minor difference in antenna tuning if phone is sold as world-phone (quad band GSM) or US (CDMA, sold by Verizon and Sprint) but I doubt that difference can be seen in battery consumption. More important is the difference in type of TX/RX-radio circuits in these two models. It can also exist other models of hardware, guess model sold in China are slightly different, but nothing I know about.

As GSM bands also differ in frequency between different locations and especially US relative rest of the world, can that be an factor also and in general can it be assumed that lower frequency costs more TX power.

Main battery life factors due to different countries are what services you have active and how good coverage are for these. If you have services active in a country that not even provide that system will it cost battery with no use.
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