The basic working principle of Cell Phone Signal Boosters is: use the forward antenna (donor antenna) to receive the downlink signal of the base station into the repeater, amplify the useful signal through the low-noise amplifier, suppress the noise signal in the signal, and improve the signal-to-noise ratio ( S/N); then down-converted to IF signal, filtered by filter, IF amplified, frequency-shifted and up-converted to RF, amplified by power amplifier, and transmitted to mobile station by backward antenna (retransmission antenna).
