Provided is an amplifier structure. The amplifier structure includes a delta-sigma modulator, an up converter, a power amplifier, and a band-pass filter. The delta-sigma modulator receives an IF signal to delta-sigma modulate the IF signal. The up converter up-converts a frequency of the delta-sigma modulated signal with an LO signal. The power amplifier amplifies a power of the up-converted signal. The band-pass filter filters the amplified signal of a selected band. The amplifier structure performs the delta-sigma modulation operation on an IF input signal, and thus can considerably decrease a delta-sigma modulation operation speed compared to a typical amplifier structure and moderate the specification in implementing a power amplifier.