The SMC-3540 from Sierra Microwave Technology is a RF & Microwave Circulator with Frequency 35 to 40 GHz, Average Power Reverse 2 to 150 W, Insertion Loss 1 dB, Isolation 16 dB, Operating Temperature -54 to 85 Degree C. Tags: Coaxial Circulator. More details for SMC-3540 can be seen below.