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abstract: |
    To exploit synergies between the [*Herschel*]{} Space Observatory and next generation radio facilities, we have extended the semi-empirical extragalactic radio continuum simulation of Wilman et al. to the mid- and far-infrared. Here we describe the assignment of infrared spectral energy distributions (SEDs) to the star-forming galaxies and active galactic nuclei, using [*Spitzer*]{} 24, 70 and 160 and [*SCUBA*]{} 850 survey results as the main constraints.

    Star-forming galaxies dominate the source counts, and a model in which their far-infrared–radio correlation and infrared SED assignment procedure are invariant with redshift underpredicts the observed 24 and 70 source counts. The 70 deficit can be eliminated if the star-forming galaxies undergo stronger luminosity evolution than originally assumed for the radio simulation, a requirement which may be partially ascribed to known non-linearity in the far-infrared–radio correlation at low luminosity if it evolves with redshift. At 24, the shortfall is reduced if the star-forming galaxies develop SEDs with cooler dust and correspondingly stronger Polycyclic Aromatic Hydrocarbon (PAH) emission features with increasing redshift at a given far-infrared luminosity, but this trend may reverse at $z>1$ in order not to overproduce the sub-mm source counts. The resulting model compares favourably with recent [*BLAST*]{} results and 