Regarding smart phone antennas

[ram@419]

HI
I have a simple doubt on smart phones.
smart phones can be used for voice calls,data browsing,fm,video calls,multi media services etc.

does all the above services have same frequency.
FM -88 TO 108
GSM 890Mhz around
like the above mentioned different services has different frequencies.
Is there a single antenna for all these services ?
please clarify me how it is going to work?

Thanks and regards
Ram.

 

[tpetar]

How FM radio stations broadcast radio program over Internet? :smile:

Some devices can have builtined real FM tuner, and for antenna is used connection cable for handsfree. This works separated from cell phone network. Also there is devices with TV tunner inside, which have connection point with external TV antenna. All FM and TV also can be received over digital network such as Internet, in digital form.


You can find over Google lots of useful informations and diagrams as answer on your question.


Mobile Phone Frequencies
http://whirlpool.net.au/wiki/mobile_phone_frequencies
http://www.wpsantennas.com/cellular-frequency-information.aspx


Cellular frequencies
http://en.wikipedia.org/wiki/Cellular_frequencies

GSM frequency bands
http://en.wikipedia.org/wiki/GSM_frequency_bands



Radiofrequency Fields from Mobile Phone Technology
http://www.iegmp.org.uk/documents/iegmp_4.pdf


:wink:

 

[ram@419]

How FM radio stations broadcast radio program over Internet? :smile:

Some devices can have builtined real FM tuner, and for antenna is used connection cable for handsfree. This works separated from cell phone network. Also there is devices with TV tunner inside, which have connection point with external TV antenna. All FM and TV also can be received over digital network such as Internet, in digital form.


You can find over Google lots of useful informations and diagrams as answer on your question.


Mobile Phone Frequencies
http://whirlpool.net.au/wiki/mobile_phone_frequencies
http://www.wpsantennas.com/cellular-frequency-information.aspx


Cellular frequencies
http://en.wikipedia.org/wiki/Cellular_frequencies

GSM frequency bands
http://en.wikipedia.org/wiki/GSM_frequency_bands



Radiofrequency Fields from Mobile Phone Technology
http://www.iegmp.org.uk/documents/iegmp_4.pdf


:wink:

hi thanks for information.
in our mobiles does both data and voice will be in the same frequency bands or different?

 

[tpetar]

Cell-phone Channels
https://electronics.howstuffworks.com/cell-phone2.htm

Digital phones convert your voice into binary information (1s and 0s) and then compress it (see How Analog-Digital Recording Works for details on the conversion process). This compression allows between three and 10 digital cell-phone calls to occupy the space of a single analog call.


https://electronics.howstuffworks.com/cell-phone7.htm
https://electronics.howstuffworks.com/cell-phone8.htm


Digital cell phones use the same radio technology as analog phones, but they use it in a different way. Analog systems do not fully utilize the signal between the phone and the cellular network, analog signals cannot be compressed and manipulated as easily as a true digital signal. This is the reason why many cable companies are switching to digital so they can fit more channels within a given bandwidth. It is amazing how much more efficient digital systems can be.

Many digital cellular systems rely on frequency-shift keying (FSK) to send data back and forth over AMPS. FSK uses two frequencies, one for 1s and the other for 0s, alternating rapidly between the two to send digital information between the cell tower and the phone. Clever modulation and encoding schemes are required to convert the analog information to digital, compress it and convert it back again while maintaining an acceptable level of voice quality. All of this means that digital cell phones have to contain a lot of processing power!

https://www.mat.ucsb.edu/~g.legrady/academic/courses/03w200a/projects/wireless/cell_technology.htm

 

[E Kafeman]

FM is normally 76-108 MHz if same phone should cover FM broadcast for most countries. Actually shown frequency band is limited by localized software.
Embedded FM and TV antennas: **broken link removed**
2G, 3G: Same multi-resonant antenna should cover 3 -5 frequency bands. Actual used frequency-bands differ in different parts of the world.
4G/LTE: As 3G + some additional bands but to achieve high bandwidth must it exist two almost identical antennas in the phone.
GPS/GNSS has its own antenna.
Bluetooth/Wlan can often share same antenna.
RFID/NFC is a separate antenna.
Wireless charging do also require an antenna (eg. a big coil).
Many other types of antennas occur more or less commonly: for medical proposes, L-band special TV service, wireless hearing aid coil, extra FM antenna for the inbuilt transmitter, satellite antennas.
Embedded shortwave receiver antenna, is a small ferrite coil. Most common in South America.
As far as I know do no company any longer produce cellphones with inbuilt DECT phone, so these antennas are not any longer needed. It was else a nice feature.

 

[FvM]

Mobile phones have optimized antennas for 900/1800 MHz GSM bands. If they offer FM radio as additional feature, they most likely use the same antenna for it, accepting less than optimal operation of the now electrical small antenna for this purpose.

 

[E Kafeman]

Cheap FM antenna solution use headset cable as antenna, that is a good solution as long as you dont forget to bring that cable with you. A more exclusive solution use internal FM/TV antenna. Performance is assumed to be about the same for FM and for TV is internal antenna in most cases better performing then a headset cable. It is not possible to use a GSM antenna for FM/TV reception for a number of reasons. Same phone should often fit different market and upper UHF will then collide with Lower GSM/LTE bands causing poor performance for both.
A GSM antenna, even if it was possible to use it as FM antenna would performance be too low. Follow my link above and see how a embedded FM/TV solutions looks like.
As a embedded FM/TV antenna is very small compared to wavelength, must bandwidth be kept narrow to not get too low efficiency. To cover whole FM band is antenna tuned with a varactor diode. It is not popular to place a varactor diode on an antenna that also can transmit due to that it will cause high harmonics. Similar solution is used also for the TV antenna but with wider tuned bandwidth. As the antenna from Ethertronics is intended for DVB-h must it fulfill a minimum required efficiency set by MBRAI. As far as I know is this the smallest antenna that have achieved that. For FM antenna have I now developed an smaller and somewhat better performing antenna (8*8*4 mm) but I doubt that it will be produced as both radio and TV have been reduced to a streamed function in most modern cellphones.

 

[FvM]

Thanks for reminding the tuned Ethertronic antennas. Dynamical tuning seems in fact as the the only means to achieve an acceptable gain of electrical small antennas in presence of "hand" and similar effects. I prevously tested "chip" antennas for 434 MHz ISM band, their behaviour is simply awful.

I also wonder how varactor tuned antennas deal with intermodulation and if the Ethertronics transmitter antennas are able to keep the regulations for harmonic emissions?

You're indeed right about the trivial option to use the headset cable for FM receiption. I find it mentioned in mobile phone FAQ: No FM radio on speaker without conncted headphone.

 

[E Kafeman]

As these tuned FM/TV antennas are RX only and have low coupling effect to the other internal antennas is intermodulation a minor problem. Worst problem with these real small antennas, compared with for example a headset cable is that the internal RX antennas suffer much more from wideband internal in phone generated EMI as they are several times closer to the actual noise source. A bad location and high antenna efficiency is not worth anything.
Ceramic mini antennas are often better described as counterweight to the ground plane. With a well tuned ground plane can they perform better then expected.

 

[tony_lth]

In a smart phone, there is 7 antennas for various applications except FM antenna.
FM antenna uses headset.

 

[FvM]

there is 7 antennas

GSM, GPS, Bluetooth/WLAN, FM... What else?

 

[E Kafeman]

Most phones use headset as antenna but Nokia 5030, x2, x6 and a few more Nokia cell phones have internal FM antenna.
Those rather old phone models does maybe not count as a smartphones any longer?
Nokia 603 is however still a rather modern and smart Symbian phone, with internal FM antenna for both TX and Rx.
Perfect phone if you want something that can handle a few hours talk-time, still with a week between each battery charging.
Can it be smarter then that?

 

[volker_muehlhaus]

GSM

There are many different mobile phone bands/standards in today's phones, operating at different frequencies.

 

[FvM]

There are many different mobile phone bands/standards in today's phones, operating at different frequencies.

Of course, but they are usually handled by a single multiband anatenna.

 

[tony_lth]

LTE needs two antennas, one for main and the other is for diversity.
One US band is 700MHz, and another band may be used 2600MHz, that can't be ermgered sometimes for optimise.
So low band may denotes 1700MHz ~ 2200MHz, high band denotes 2200MHz ~ 2700 MHz.