The ZVA67 vector network analyser from Rohde & Schwarz is available as a four-port model.
The four test ports can be used for measurements up to 67GHz, and the dynamic range is 110dB at 67GHz, with output power of 6dBm at 67GHz.
Intended for characterising components and modules in the microwave and millimeter-wave range, it can typically be used for measuring the S parameters or intermodulation of mixers or amplifiers, or measuring the group delay and phase of up- or downconverters.
The analyser's dynamic range also makes it applicable to material measurements or microwave imaging applications.