\begin{table}%t3
\vspace{-2mm}\caption{\label{TabPolChar}Predicted in-flight main beam polarisation properties\tablefootmark{a}.}
%\centering
\par
\begin{tabular}{p{2cm}p{1cm}p{0.45cm}p{0.45cm}p{0.45cm}p{0.45cm}p{0.45cm}p{0.45cm}p{0.45cm}p{0.45cm}p{0.45cm}}        
\hline\hline \noalign{\smallskip}                
Frequency (GHz)& No. det.  & \multicolumn{3}{c}{Angle Uncertainty (deg)\tablefootmark{b}} & \multicolumn{3}{c}{Cross-polar level (\%)\tablefootmark{c}} & \multicolumn{3}{c}{$X$-$Y$ Mismatch\tablefootmark{d} (\%)}\\   
 &  & Mean & Min & Max & Mean & Min & Max & Mean & Min & Max\\
\hline                         
30 & 4 & 0.06 & -- & -- & 0.05 & 0.05 & 0.05 & 1.37 & 1.37 & 1.37 \\
44 & 6 & 0.06  & -- & -- & 0.11 & 0.04 & 0.14 & 2.40 & 2.03 & 2.58 \\
70 & 12 & 0.06  & -- & -- & 0.04 & 0.03 & 0.05 & 1.19 & 1.00 & 1.31 \\
\hline
100 & 8 & 0.82 & 0.33 & 1.47 & 3.4 & 1.95 & 5.13 & 0.41 & 0.40 & 0.43 \\
143 & 8 & 0.54 & 0.34 & 0.83 & 6.4 & 3.57 & 9.15 & 0.92 & 0.86 & 0.97 \\
143 (unpol) & 4 & 4.95 & 1.28 & 8.58 & 93.2 & 87.6 & 96.9 & -- & -- & --  \\
217 & 8 & 0.61 & 0.35 & 1.27 & 2.8 & 2.46 & 3.27 & 0.78 & 0.70 & 0.90  \\
217 (unpol) & 4 & 6.9 & 4.78 & 9.76 & 93.3 & 92.1 & 95.9 & -- & -- &  -- \\
353 & 8 & 0.81 & 0.40 & 2.09 & 6.1 & 4.13 & 8.29 & 0.60 & 0.58 & 0.62 \\
353 (unpol)  & 4 & 4.58 & 2.29 & 7.23 & 88.7 & 85.0 & 93.5 & -- & -- & -- \\
545 (unpol) & 4 & 2.68 & 0.67 & 4.15 & 89.8 & 88.8 & 91.1 & -- & -- &  -- \\
857 (unpol) & 4 & 8.7 & 2.42 & 20.79 & 86.6 & 84.2 & 88.2 & -- & -- &  -- \\
\hline                                    
\end{tabular}
\tablefoot {\tablefoottext{a}{The data presented correspond to monchromatic beams at band centre. The HFI spider-web bolometers are slightly polarised and therefore they are also included in this table.} \\
\tablefoottext{b}{The uncertainty in the angle of the principal plane of polarisation, at focal plane level (the systematic uncertainty of a rigid rotation of the focal plane is very low as it will be measured in-flight very accurately, see Sect.~7). The differences between the design angle and the angle measured at focal plane level are within~3\degr\ for HFI; the measurement was made using a source which filled the beam to $-$20~dB. For LFI the 1$\sigma$~angle uncertainty is estimated from the mechanical manufacture and assembly tolerances, plus a model of thermoelastic deformations. However, the~total angle uncertainty for LFI detectors may be dominated by
cross-polar effects in the optical chain (telescope, horn, and mainly OMT) rather than the mechanical tolerances (see Sect.~4 and Leahy et~al. \cite{LFIPol}).} \\
\tablefoottext{c}{The fraction of power detected from incident radiation linearly polarised in the direction orthogonal to the principal plane of polarisation and hence contributing to apparent
depolarisation.} \\
\tablefoottext{d}{Maximum RF power reaching one detector minus that reaching the orthogonal detector, normalised to the highest of the two (this definition is a factor of 2~larger than the leakage of Stokes~I to~Q ($M_{\rm QI}$) defined in Leahy et~al. \cite{LFIPol}).}}
\vspace{-1.8mm}\end{table}