Effective radiated power

== Polarization ==
Polarization has not been taken into account so far, but it must be properly clarified.  When considering the dipole radiator previously we assumed that it was perfectly aligned with the receiver.  Now assume, however, that the receiving antenna is circularly polarized, and there will be a minimum 3&nbsp;dB polarization loss ''regardless'' of antenna orientation.  If the receiver is also a dipole, it is possible to align it orthogonally to the transmitter such that theoretically zero energy is received.  However, this polarization loss is not accounted for in the calculation of ERP or EIRP.  Rather, the receiving system designer must account for this loss as appropriate.  For example, a cellular telephone tower has a fixed linear polarization, but the mobile handset must function well at any arbitrary orientation.  Therefore, a handset design might provide dual polarization receive on the handset so that captured energy is maximized regardless of orientation, or the designer might use a circularly polarized antenna and account for the extra 3&nbsp;dB of loss with amplification.