The 1720BL15B0050 from Johanson Technology is a wideband ceramic balun that operates from 628 to 2815 GHz. It has a 1:1 Impedance ratio with an unbalanced/balanced port impedance of 50 Ohms. The balun has an insertion loss of 1.5 dB, return loss of 9.5 dB and can handle up to 2 W of power.