An intermediate frequency (IF) amplifier is proposed, which is wideband, high gain, and low noise. It is supposed to be applied to 300 GHz wireless systems. It consists of one stage of common gate (CG) and three stages of common source (CS). The input impedance of CG stage is analyzed to get wide band matching. And capacitor cross-coupled (CCC) feedback is employed to increase the gain of CS stage. The IF amplifier has 40 dB peak gain at 17.5 GHz, and the 3 dB bandwidth of 9.5 GHz from 10.5-20 GHz. The noise figure (NF) is 3.5-6 dB over the frequency range. And the power consumption is 72 mW.