Abstract:We report a Ka-band monolithic frequency quadrupler with high dynamic range and harmonics efficient rejection based on 0.15 µm GaAs PHEMT process in this letter. The quadrupler is constructed a drive power amplifier, a one-stage active quadrupling part, a high-pass filter, and a threestage power amplifier of the fourth harmonic. Efficient harmonics rejection is realized by harmonic restrain structure inside the quadrupling part and the filter between the quadrupling part and the output amplifier. According to the measured results, the output power reaches 20 dBm when input power ranges from −5 dBm to 1 dBm at an input frequency of 8.5 GHz. The harmonics rejections are larger than 40 dBc. The overall chip size is 3 × 2.2 mm 2 .