The D3I3442 from DiTom Microwave is an RF Isolator that operates from 3.4 to 4.2 GHz. It can handle an average input power of up to 20 W, a peak input power of 30 W, and a reflective power of 2 W. This isolator provides an isolation of more than 20 dB and has an insertion loss of less than 0.4 dB. It is available in a module that measures 2.27 x 1.40 x 0.70 mm with SMA-male/female connectors.
