CMB foreground measurements through broad-band radio
  spectro-polarimetry: prospects of the SKA-MPG telescope
  Precise measurement of the foreground synchrotron emission, which
contaminates the faint polarized cosmic microwave background radiation (CMB),
is a major challenge for the next-generation of CMB experiments. To address
this, dedicated foreground measurement experiments are being undertaken at
radio frequencies between 2 and 40 GHz. Foreground polarized synchrotron
emission measurements are particularly challenging, primarily due to the
complicated frequency dependence in the presence of Faraday rotation, and are
best recovered through broad fractional-bandwidth polarization measurements at
frequencies $\lesssim 5$ GHz. A unique opportunity for measuring the foreground
polarized synchrotron emission will be provided by the 15-m SKA-MPG telescope
operating in the frequency range 1.7 to 3.5~GHz (S-Band). Here, we present the
scope of a Southern sky survey in S-Band at 1 degree angular resolution and
explore its added advantage for application of powerful techniques, such as,
Stokes $Q$, $U$ fitting and RM-synthesis. A full Southern-sky polarization
survey with this telescope, when combined with other on-going efforts at
slightly higher frequencies, will provide an excellent frequency coverage for
modeling and extrapolating the foreground polarized synchrotron emission to CMB
frequencies ($\gtrsim80$~GHz) with rms brightness temperature better than 10~nK
per 1 degree$^2$. We find that this survey will be crucial for understanding
the effects of Faraday depolarization, especially in low Galactic latitude
regions. This will allow better foreground cleaning and thus will contribute
significantly in further improving component separation analyses and increase
usable sky area for cosmological analysis of the \textit{Planck} data, and the
\textit{LiteBIRD} mission in the future.
