\begin{table}%t5
\caption {\label{tab:basic_performances}Receiver basic properties: gain, noise temperature, and \mbox{linearity}. }            
%\centering
                          % used for centering table
\begin{tabular}{l l r r r r}        % centered columns (4 columns)
\hline\hline                 % inserts double horizontal lines
\noalign{\smallskip}
 & & \multicolumn{4}{c}{G{\sc ain} (V/K), $T_{\rm n}$ (K), {{\sc and} L{\sc in}}}\\
 & & M-00 & M-01 & S-10 & S-11 \\    % table heading 
\hline                        % inserts single horizontal line
{\tt RCA18}  & $G_0$ & 0.0173 &	0.0195 &	0.0147	& 0.0143 \\
             & $T_{\rm n}$  & 36.0 & 36.1& 33.9 & 35.1 \\
          {\tt RCA19}  & $G_0$ & 0.0161 &	0.0174 &	0.0176 &	0.0196 \\
             & $T_{\rm n}$ & 33.1 & 31.5 & 32.2 & 33.6 \\
          {\tt RCA20}  & $G_0$ & 0.0186 &	0.0164 &	0.0161 &	0.0165\\
             & $T_{\rm n}$ & 35.2 & 34.2 &	36.9 & 35.0 \\
{\tt RCA21}  & $G_0$ & 0.0161 &	0.0154 &	0.0119 &	0.0114\\
             & $T_{\rm n}$ & 27.3 & 28.4 & 34.4 & 36.4 \\
{\tt RCA22}  & $G_0$ & 0.0197 &	0.0174 &	0.0165 &	0.0163 \\  
             & $T_{\rm n}$ & 30.9 & 30.3 & 30.3 & 31.8 \\
{\tt RCA23}  & $G_0$ & 0.0149	& 0.0171 &	0.0271 &	0.0185\\
             & $T_{\rm n}$ & 35.9 & 34.1 & 33.9 & 31.1 \\
{\tt RCA24}  & $G_0$   & 0.0048 &	0.0044 &	0.0062 &	0.0062 \\
             & $T_{\rm n}$ & 15.5	& 15.3 &	15.8 &	15.8 \\
             & $b$     &1.79	& 1.49 &	1.44 &	1.45 \\
{\tt RCA25}  & $G_0$   & 0.0086	& 0.0085 &	0.0079 &	0.0071 \\
						 & $T_{\rm n}$ & 17.5	& 17.9 &	18.6 &	18.4\\
\par
             & $b$     & 1.22	& 1.17 &	0.80 &	1.01\\
{\tt RCA26}  & $G_0$   & 0.0052	& 0.0067 &	0.0075 &	0.0082\\
						 & $T_{\rm n}$ & 18.4	& 17.4 &	16.8 &	16.5 \\
             & $b$     & 1.09	& 1.42 &	0.94 &	1.22\\
{\tt RCA27}  & $G_0$   & 0.0723	& 0.0774 &	0.0664 &	0.0562\\
						 & $T_{\rm n}$ & 12.1	& 11.9 &	13.0 &	12.5\\
             & $b$     & 0.12	& 0.12 &	0.13 &	0.14\\
{\tt RCA28}  & $G_0$   & 0.0621 &	0.0839 &	0.0607 &	0.0518\\
						 & $T_{\rm n}$ & 10.6	& 10.3 &	9.9 &	9.8\\
             & $b$     & 0.19	& 0.16 &	0.19 &	0.20\\
\hline                                   %inserts single line
\end{tabular}
\tablefoot{For the $70$~GHz RCAs, the gain, $G_0$, and the noise temperature, $T_n$, were derived from the linear fit, and the linearity coefficient is not reported. For $30$ and $44$ GHz, $G_0$, 
$T_n$, and the linearity coefficient, $b$, were derived from the gain model-fit.}
\end{table}