The 1221B-36AC from ACST GmbH is a Frequency Multiplier with Input Frequency 13.88 to 20.83 GHz, Output Frequency 500 to 750 GHz, Input Power 0 to 5 dBm, Output Power -12 to -3 dBm, VSWR 1.80:1. Tags: Waveguide, Waveguide Multiplier. More details for 1221B-36AC can be seen below.