Question about polarization and mobile antennas

[saif haider]

polarization

why polrization is taken so seriouly in case of dipoles monopoles but when we take about mobile their is also antenna in it, why we dont cosider its orientation either horizontal or vertical. it is some times in pocket and sometimes placed on table and their is no effect. have some one got any explanation on this.

 

[biff44]

Re: polarization

Why?

1) handheld apps are too small to use a dual polarization antenna

2) many apps naturally orient the antenna in the vertical polarization, ie. cell phone with antenna always pointing up

3) In mobile applications where there are lots of reflections and multipath, the polarization shifts to almost anything you want, so it is less important.


Now, in other applications where things are fixed, high quality electronics are used, and the antenna is far above the earth, then polarization is very important. Some telephone backhaul services actually send one set of data on one polarization, and a completely different set of data over the crosspolarization, and the same frequency. There they are really counting on the antenna to cancel the cross-pol interfering signal!

 

[saif haider]

Re: polarization

Why?

1) handheld apps are too small to use a dual polarization antenna

2) many apps naturally orient the antenna in the vertical polarization, ie. cell phone with antenna always pointing up

3) In mobile applications where there are lots of reflections and multipath, the polarization shifts to almost anything you want, so it is less important.


Now, in other applications where things are fixed, high quality electronics are used, and the antenna is far above the earth, then polarization is very important. Some telephone backhaul services actually send one set of data on one polarization, and a completely different set of data over the crosspolarization, and the same frequency. There they are really counting on the antenna to cancel the cross-pol interfering signal!

i mean to say why their is no effect if antenna is always pointing up then why it is not bothering the reciever that are the antenna of mobile companies that have their own antenna in one orientations

 

[Azulykit]

Re: polarization

Polarization is a very real issue. Careful testing on a clean range can easily measure a 30 dB change in signal level.

Another thing to consider: circular polarized antennas tend to be less orientation dependant. That is one reason for chosing that option. It is still possible to get cross polarized and loose signal. A linear to circular antenna appears to be orientation independant as well.