\begin{table}%t2
\caption{\label{table:1}Predicted in-flight beam properties\tablefootmark{a}.}
%\centering
\par
\begin{tabular}{p{1.5cm}p{0.5cm}p{0.6cm}p{0.6cm}p{0.6cm}p{1.0cm}p{0.5cm}p{0.5cm}p{0.5cm}p{1.2cm}p{0.5cm}p{0.5cm}p{0.5cm}p{0.5cm}p{0.5cm}p{0.5cm}}        
\hline\hline \noalign{\smallskip}                 
Frequency (GHz)& No. det. & \multicolumn{3}{c}{{\it FWHM}\tablefootmark{b} (arcmin)} & Band-averaged
{\it FWHM}\tablefootmark{c}
 & \multicolumn{3}{c}{Ellipticity\tablefootmark{d}} & Band-averaged
Ellipticity\tablefootmark{e} &
\multicolumn{3}{c}{SR Spillover\tablefootmark{f}
(\%)} & \multicolumn{3}{c}{PR Spillover\tablefootmark{g} (\%)}
\\     
 &  & Mean & Min & Max & Mean & Mean & Min & Max & Mean & Mean & Min & Max & Mean & Min & Max\\
\hline                         
30 & 4 & 33.34 & 33.33 & 33.35 & 32.71 & 1.38 & 1.36 & 1.40 & 1.36 & 0.24 & 0.23 & 0.24 & 0.59 & 0.59 & 0.59 \\
44 & 6 & 26.81 & 22.96 & 29.14 & 29.54 & 1.26 & 1.21 & 1.37 & 1.50 & 0.07 & 0.03 & 0.09 & 0.18 & 0.14 & 0.19 \\
70 & 12 & 13.03 & 12.76 & 13.38 & 13.00 & 1.22 & 1.20 & 1.26 & 1.27 & 0.17 & 0.12 & 0.19 & 0.65 & 0.54 & 0.76 \\
\hline
100 & 8 & 9.40 & 8.62 & 10.21 & 9.58 & 1.18 & 1.17 & 1.18 & 1.17 & 0.19 & 0.17 & 0.21 & 0.14 & 0.12 & 0.16  \\
143 & 8 & 6.79 & 6.54 & 7.12 & 6.93 & 1.06 & 1.03 & 1.09 & 1.06 & 0.19 & 0.19 & 0.19 & 0.11 & 0.10 & 0.11 \\
143 (unpol) & 4 & 6.99 & 6.85 & 7.21 & 7.11 & 1.04 & 1.03 & 1.05 & 1.03 & 0.19 & 0.19 & 0.19 & 0.13 & 0.13 & 0.13 \\
217 & 8 & 4.57 & 4.31 & 4.84 & 4.63 & 1.10 & 1.08 & 1.12 & 1.10 & 0.10 & 0.10 & 0.11 & 0.07 & 0.02 & 0.09 \\
217 (unpol) & 4 & 4.57 & 4.29 & 4.87 & 4.62 & 1.12 & 1.11 & 1.13 & 1.12 & 0.12 & 0.12 & 0.12 & 0.12 & 0.12 & 0.12 \\
353 & 8 & 4.52 & 4.28 & 4.76 & 4.52 & 1.08 & 1.06 & 1.11 & 1.08 & 0.02 & 0.02 & 0.02 & 0.02 & 0.02 & 0.02 \\
353 (unpol) & 4 & 4.60 & 4.04 & 5.27 & 4.59 & 1.25 & 1.19 & 1.31 & 1.23 & 0.02 & 0.02 & 0.02 & 0.02 & 0.02 & 0.02 \\
545 (unpol) & 4 &  &  &   & 4.7\tablefootmark{h} &  &  &  & 1.03 & 0.02 &  &  & 0.3 &  & \\
857 (unpol) & 4 &  &  &  & 4.3&  &  &  & 1.04 & 0.0001 &  &  & 0.03 &  & \\
\hline                                    
\end{tabular}
\tablefoot {\tablefoottext{a}{The characteristics listed in this table correspond to those of monochromatic beams at band centre; the typical effect of including band-averaging is indicated for {\it FWHM} and ellipticity. Mean, minimum, and maximum are drawn from the set of all detectors at a given frequency; polarised and unpolarised detectors are separately indicated.} \\
\tablefoottext{b}{The mean of the minor and major axis at half-power found by fitting a bivariate Gaussian to the beam.} \\
\tablefoottext{c}{Mean {\it FWHM} (in arcmins) for beams averaged across the detector bandwidth, based on straight averaging of 5~frequencies equally spaced within the bandpass. This is indicative only, as~it does not account for the bandpass shape of the detector, nor for the spectrum of the source. A~more optimal way to account for broadband optical effects in the near sidelobes is described in Yurchenko et~al. (\cite{Yurchenko2005}); their analysis indicates that the effect of
increasing the number of frequencies averaged from~3 to~9 is well below~1\% in total power.} \\
\tablefoottext{d}{The ratio of major and minor axis.} \\
\tablefoottext{e}{Mean ellipticity of beams averaged across the detector bandwidth. This is indicative only, as~for the {\it FWHM}.} \\
\tablefoottext{f}{The percentage of power reaching the detector without having reflected on either SR or~PR.} \\
\tablefoottext{g}{The percentage of power reaching the detector having reflected only on the SR.} \\
\tablefoottext{h}{Since the shape of the multi-moded beam patterns is not Gaussian, the {\it FWHM}  only partially represents~it. A~different parameter to use is the half-power angle in the azimuthally integrated power, whose mean is~4.08 and 3.3~arcmins for~545 and 857~GHz, respectively.}
}
\vspace*{6.2mm}
\end{table}