Patent ID: 7792501

Claim:
An apparatus for attenuating a leakage signal of a radio frequency (RF) transmitter, the apparatus comprising: a local oscillator for outputting a reference frequency signal; a mixer for adding the reference frequency signal to an intermediate frequency (IF) signal to convert the IF signal into an RF signal, and for outputting the RF signal, a leakage signal and an image signal; and a leakage signal attenuator including a signal dividing block for extracting a partial signal from the reference frequency signal output from the local oscillator, a phase shift block for adjusting the amplitude of the extracted signal and for shifting the phase of the extracted signal, and a signal combining block for combining an output signal of the phase shift block and the output signal of the mixer to remove the leakage signal, wherein the phase of the extracted signal is shifted by an amount corresponding to the addition of 180° to a resulting value of a difference between a phase shift of the extracted signal from the signal dividing block to the phase shift block and a phase shift of the extracted signal from the phase shift block to the signal combining block from a phase shift of the reference frequency signal throughout the signal dividing block, the mixer and the signal combining block.