The APT4-20202120-1708-D4 from AmpliTech, Inc. is a RF Amplifier with Frequency 20.2 to 21.2 GHz, Gain 22 dB, Gain Flatness ±1.75 dB, Noise Figure 1.70 dB, IP3 35 to 37 dBm. Tags: Low Noise Amplifier. More details for APT4-20202120-1708-D4 can be seen below.