Concerning the polarization:
Cell phone antennas are often linearly polarized, so rotating the phone can often match the polarization of the phone and thus increase reception.
However, circular polarization is a desirable characteristic for many antennas. Two antennas that are both circularly polarized do not suffer signal loss due to polarization mismatch. For instance, antennas used in GPS systems are Right Hand Circularly Polarized.
Concerning the impedance bandwidth of a mobile phone:
There's no fixed "VSWR rules" for cell phone design. Most people who don't work on antennas will tell you that the Antenna's Impedance is matched to 50 Ohms. However, given the relatively small volume of the antenna and relatively large required bandwidth, the impedance is rarely if ever exactly 50 Ohms. Typically the VSWR is less than 3, with 2 being very acceptable.
Hello,
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Linear polarization is by far the most widely used for most radio communications applications. Vertical polarisation is often used for mobile radio communications. This is because many vertically polarized antenna designs have an omni-directional radiation pattern and it means that the antennas do not have to be re-orientated as positions as always happens for mobile radio communications as the vehicle moves.
from:
http://ing.dk/artikel/spoerg-laeserne-kan-en-kobberledning-forstaerke-mobilsignalet-174413
http://www.radio-electronics.com/info/antennas/basics/polarisation-polarization.php
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