The SMD1300-T0390 from Mercury Systems is a RF & Microwave Circulator with Frequency 3.6 to 4.2 GHz, Bandwidth 600 MHz, Average Power Forward 5 W, Average Power Reverse 1 W, Insertion Loss 0.5 dB. Tags: Microstrip Circulator. More details for SMD1300-T0390 can be seen below.