The L5540 from Mercury Systems is a Diplexer with Frequency f1 1.564 to 1.586 GHz, Frequency f2 1.216 to 1.238 GHz, Insertion loss 1 dB, Frequency 1.564 to 1.586 GHz / 1.216 to 1.238 GHz, Return Loss 17.6 dB. Tags: Module with Connectors, Cavity. More details for L5540 can be seen below.