A frequency multiplier (200) generates an output signal with a frequency 3 times of the input signal frequency. The frequency multiplier (200) comprises four cascaded stages. A first stage (201) is configured to receive an input signal and generate harmonics signals of the input signal. A second stage (202) is a passive filter, a frequency response of the passive filter has either a peak or a dip around an upper frequency end of a frequency band of the input signal. A third stage (203) is configured to mix the 1st and the 2nd order harmonics signals to generate 3rd order harmonic signals. A fourth stage (204) is configured to suppress the 1st and even-order harmonics signals and output a signal dominated with a frequency 3 times of the input signal frequency.
展开▼