[Tex/LaTex] Double column table IEEE & one “invisible” column in the table

tables

i'm trying to create a table for my ongoing paper for IEEE , the table should spread over two columns , so I tried to use the "*" command, but it is just hovering on the 3rd page in the middle of it and not spreading over the two columns. I reallt don't know what are all the "C{#}" I just copied it from one example that I saw on the web.

Also i'd like to merge or split the "Term" column such that, the Symbol would be in the 1st column and its description would be in the 2nd column, but both would be under "Term" (I don't know what is the English term for this action, sorry).

Here is my table 

\documentclass[10pt,journal,final]{IEEEtran}
\usepackage[cmex10]{amsmath}
\interdisplaylinepenalty=2500
\usepackage{float}
\usepackage{tabularx,ragged2e,booktabs,caption}
\newcolumntype{C}[1]{>{\Centering}m{#1}}
\renewcommand\tabularxcolumn[1]{C{#1}}


\markboth{JOURNAL OF LIGHTWAVE TECHNOLOGY,~Vol.~???, No.~???, September~????}%
{Shell \MakeLowercase{\textit{et al.}}: Bare Demo of IEEEtran.cls for Journals}
\begin{document}
\begin{table*}[!htbp]
\centering
\captionof{table}{Link budget parameters} 
\begin{tabular}{ C{1.25in} C{.85in} C{.75in}C{.75in}C{.75in}C{.75in}}\toprule[1.5pt]
\bf Term & \bf Formula &\bf Parameter \\\midrule
$P_{tr}$  Transmitted power      &  According to Eq.\ref{linkbudget} &Calculated     \\
\midrule
$G_{tr}$ Transmitting antenna gain & $\left(\frac{\pi D_tr}{\lambda}\right)^2$ & $D_{tr = 5[cm]}$, transmitter aperture diameter;$\lambda=800[nm]$ \\
\midrule
$G_{MRR}$  MRR gain & $\left(\frac{\pi D_{MRR}}{\lambda}\right)^4$&$D_{MRR}=1[cm]$,MRR aperture diameter\\
\midrule
$G_r$  Receiving antenna gain & $\left(\frac{\pi D_{rec}}{\lambda}\right)^2$ & $D_{rec}=5[cm]$, receiver aperture diameter \\
\midrule
$M$  Modulation efficiency & $e^{-\sum\limits_{N}^{}\alpha_{off}^N} \prod\limits_{N}^{}\left(C_m^N-1\right)$&$\alpha_{off}^N$ absorption in off state of layer N; $C_m^N$ optical contrast ration of layer N\\
\midrule
$L_{fs}^2$ Free space loss & $\left(\frac{\lambda}{4\pi R}\right)^2$ & R, distance from MRR to base station \\
\midrule
$L_r$  Receiving antenna loss & & $-1.5[dB]$ assumed\\
\midrule
$L_{MRR}$ MRR loss & Due to anti-reflection & $-0.5[dB]$ assumed\\
\midrule
$P_r$ Received signal power & & Assumed\\
\bottomrule[1.25pt]
\end {tabular}\par
\bigskip
%caption
\label{tab:linkbudget_table} 
\end{table*}


\end{document}

I don't know if to open for next question another thread , because it is related to the same table , now i'm trying to put this table in my dissertation, which defined with : 

\RequirePackage[l2tabu, orthodox]{nag}
\documentclass[a4paper,onecolumn,12pt,twoside,openright,bibliography=totoc]{scrreprt}

but the text at the right most column is getting out of the page , while it should be spread across two or more rows , how can I fit to my dissertation?

Best Answer

Do you mean something like this:

enter image description here

I show only few first rows of table, other can be easily added on shoved way. This table can not appear in the first page of your article, but on the second or later page on the its top or on the bottom.

For table I use tabularx environment, redefine column type s to the left align, erase unnecessary columns and ad one on the beginning of table as you desired. I also change the formula with exponent into more readable form.

If you wish, you can change align of cells column. For example, in the first column instead center align maybe will look better right align (just change c to r).

Edit: The first version of proposed code I replaced with slightly simplified version, which gives the same result:

\documentclass[10pt,journal,final]{IEEEtran}
\usepackage[cmex10]{amsmath}
\interdisplaylinepenalty=2500
\usepackage{float}
\usepackage{tabularx,ragged2e,booktabs,caption}
\newcolumntype{L}{>{\RaggedRight\arraybackslash}X}

\usepackage{lipsum}

\markboth{JOURNAL OF LIGHTWAVE TECHNOLOGY,~Vol.~???, No.~???, September~????}%
{Shell \MakeLowercase{\textit{et al.}}: Bare Demo of IEEEtran.cls for Journals}

\begin{document}
    \lipsum[1-5]
    \begin{table*}[t]
\centering
\setlength{\tabcolsep}{3pt}
\caption{Link budget parameters}
    \label{tab:linkbudget_table}
\begin{tabularx}{\hsize}{@{}>{$}r<{$:}l 
                            >{$\displaystyle}c<{$} 
                            L @{}}
    \toprule[1.5pt]
\multicolumn{2}{c}{\textbf{Term}} 
            & \textbf{Formula} &\textbf{Parameter}          \\
    \midrule
P_{tr}     
    &   Transmitted power      
        &  \text{According to Eq.\ref{linkbudget}} 
                                & Calculated                    \\
\addlinespace
G_{tr} 
    &   Transmitting antenna gain 
        &   \left(\frac{\pi D_tr}{\lambda}\right)^2 
            &   $D_{tr} = 5[cm]$, transmitter aperture diameter;
                $\lambda=800[nm]$                               \\
\addlinespace
G_{MRR}  
    &   MRR gain 
        &   \left(\frac{\pi D_{MRR}}{\lambda}\right)^4
            &   $D_{MRR}=1[cm]$,MRR aperture diameter           \\
\addlinespace
G_r &   Receiving antenna gain 
        &   \left(\frac{\pi D_{rec}}{\lambda}\right)^2
            & $D_{rec}=5[cm]$, receiver aperture diameter       \\
\addlinespace
M   &  Modulation efficiency 
        &   \exp\{-\sum\limits_{N}^{}\alpha_{off}^N\}
            \prod\limits_{N}^{}\left(C_m^N-1\right)
            &   $\alpha_{off}^N$ absorption in off state of layer $N$; 
                $C_m^N$ optical contrast ration of layer $N$    \\
\bottomrule[1.25pt]
\end{tabularx}
    \end{table*}
    \lipsum[6-17]
\end{document}
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