antenna-theory.com

[PVAMSIECE]

i want to know in which part of the cell phone antennas are placed? and also what are the differnat antennas used in cell phone towers and what for they are used?

[bigSteve]

Cell Phones today often have several antennas: WIFI, GPS, and then the Cell Antenna for voice traffic.

Typically these antennas are on the top and bottom of the cell phone, on the side that is farther from the user's head. The radiation is directed away from the ear/head in order to meet SAR requirements (Specific Absorption Rate - measures the amount of power absorbed by body tissue). These antennas can be PIFAs, patch antennas, IFAs, slots, or dipoles.

For cell towers, there are typically three antennas for each sector the antennas cover. The picture on the right on this page:
www.antenna-theory.com
shows a cell tower antenna.

Usually two of these antennas are receive antennas, and the third is the transmit antenna.

[PVAMSIECE]

thanks for ur kind information.i heard that two are three service providers use the same tower. do they use the same transmitter ?

[bigSteve]

It's possible that they would share transmit antennas but I highly doubt it. If you look at the same photo I showed earlier, there are multiple sets of antennas on there, and these could be different providers or whatever.