  We present MeqSilhouette v2.0 (MeqSv2), a fully polarimetric, time-and
frequency-resolved synthetic data generation software for simulating millimetre
(mm) wavelength very long baseline interferometry (VLBI) observations with
heterogeneous arrays. Synthetic data are a critical component in understanding
real observations, testing calibration and imaging algorithms, and predicting
performance metrics of existing or proposed sites. MeqSv2 applies physics-based
instrumental and atmospheric signal corruptions constrained by
empirically-derived site and station parameters to the data. The new version is
capable of applying instrumental polarization effects and various other
spectrally-resolved effects using the Radio Interferometry Measurement Equation
(RIME) formalism and produces synthetic data compatible with calibration
pipelines designed to process real data. We demonstrate the various corruption
capabilities of MeqSv2 using different arrays, with a focus on the effect of
complex bandpass gains on closure quantities for the EHT at 230 GHz. We
validate the frequency-dependent polarization leakage implementation by
performing polarization self-calibration of synthetic EHT data using PolSolve.
We also note the potential applications for cm-wavelength VLBI array analysis
and design and future directions.
