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how should i minimize the size of antenna which is used in cellphones? Answered


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rickharris
rickharris

10 years ago

Most modern cell phones in the Uk don't have an external aerial (antenna).


A rubber coiled aerial (antenna) would be shorter than a solid one.


In essence the length of the aerial (antenna) is fixed by the frequency in use for the most efficient range.

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frollard
frollard

Answer 10 years ago

Seconded. The antenna length is determined by a fraction of the wavelength -- certain lengths enhance/reinforce certain frequencies, while cancelling/subtracting from others. To miniaturize you can often coil or fold the antenna.

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kelseymh
kelseymh

Answer 10 years ago

I'm feeling really stupid right now. Antennae work by having the EM wave induce a current, hence the > 1/2-wavelength requirement. Since EM is (to zeroth order) transversely polarized, I don't see how a coiled up antenna could possibly work. Can you point me to a decent discussion of this (the Wikipedia article was a bit too basic, and stopped at the same dipole approximation I'm stuck on).

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frollard
frollard

Answer 10 years ago

I don't know the specifics or the physics of it -- I just know certain lengths are required based on length. I know theres a 'diy high gain antenna' for wifi, and it involves both straight lengths, and coils to get extra-awesome signal amplification and attenuation (where needed)

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NachoMahma
NachoMahma

Answer 10 years ago

.  Check the ARRL web site. If you don't find what you need quickly, let me know and I'll investigate further.
.  IIRC, a coiled antenna uses its' own inductance as a loading coil, but it has been decades since I used that stuff.

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seandogue
seandogue

10 years ago

Buy an iPhone?

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seandogue
seandogue

Answer 10 years ago

But seriously, as has already been said, if you're designing an antenna for a cell phone, then investigate "fractal antenna design" using your favorite search engine

you can use "printed circuit" or "PCB" or "circuit board layout" as adjuncts for the search term for added "hit" content.