I have, with limited success, been trying to optimise the match between simulations and data measured on a home-built HF EPR setup. My data is measured with frequencies between 128 and 660 GHz. My collaborators told me that the the instrument was setup in a "double-pass" configuration - I am not sure what this means exactly, or how I should adapt my simulation accordingly.
Yhe data was measure as a transmission signal. I also know that the phase of the radiation is not controlled explicitly.
Unless the instrument uses frequency or field modulation, or you are taking a numerical derivative, set Exp.Harmonic=0. Regarding phasing etc, it really depends on the specific instrument. In the simulation, phase can be controlled via Exp.mwPhase. If you are just measuring transmission without phase-sensitive detection on the microwave, it should be sufficient to simulate the absorption spectrum.