I've been trying to make a proper header for my lab reports, that uses a table with 2 pictures. Thing is, each cell in the table has a different length.

Using this online table generator I was kind of able to emulate the tables my university uses as headers.

The code I got is:

\documentclass[12pt,letterpaper]{article}
\usepackage[spanish]{babel}
\usepackage[utf8]{inputenc}
\batchmode
\usepackage{blindtext}
\usepackage{graphicx}
\usepackage{geometry}
\geometry{left=13mm,right=13mm,top=21mm,bottom=21mm}

\usepackage{float}
\usepackage{multicol}
\usepackage{array}

\usepackage{fancyhdr}
\pagestyle{fancy}
\usepackage{tabularx}

\begin{document}
\resizebox{\textwidth}{!}{
\begin{tabular}{|c|c|l|l|c|}
\hline
\multicolumn{4}{|c|}
Escuela de Ingeniería Eléctrica\\ Departamento de Electrónica Y
Telecomunicaciones\end{tabular}}}
&
{\includegraphics[width=1cm, height=1.10cm]{images/escudo}
\includegraphics[width=2cm, height=1.10cm]{images/eie}}
\hfill Pág.\thepage \\ \end{tabular}}}  \\

\hline

Author, ID\\ Author, ID\\ Author, ID \end{tabular}}  }
& \multicolumn{4}{c|}
{{\tiny \textsc{\begin{tabular}[c]{@{}c@{}}IE|0307 Electromagnetismo
I - I Ciclo 2018\\ Laboratorio de Electromagnetismo y
\end{tabular}}}} \\

\hline

\end{tabular}%
}
\blindtext[25]
\end{document}


And with that the result I get is this:

The thing is that I'm not familiar to the facyheader package, and I haven't been able to put that table as a header.

Also, I'm supposed to put the date beneath the page count, but I'm not able to, because of how the table is structured.

I've seen similar posts such as Table as Header and Footer and Table as Header - How to? but none are quite the same, and I've been hard stuck with this. I would greatly appreciate if you could help me understand this one.

based on my answer to question Table as Header - How to?:

\documentclass[12pt,letterpaper]{article}
%\geometry{left=13mm,right=13mm,top=21mm,bottom=21mm}

\usepackage[spanish]{babel}
\usepackage[utf8]{inputenc}
%\batchmode
\usepackage{makecell,multirow,tabularx}
\newcolumntype{C}{>{\centering\arraybackslash}X}
\usepackage[demo]{graphicx}

\usepackage{fancyhdr}
\tiny
\scshape
\setlength\extrarowheight{3pt}
\noindent\begin{tabularx}{\linewidth}{|C|C|}
\hline
Escuela de Ingeniería Eléctrica\newline
Departamento de Electrónica Y\newline
Telecomunicaciones
&   \hfill%
\includegraphics[width=1cm, height=1.10cm, valign=t, margin=0pt 3pt 0pt 0pt]{images/escudo}
\includegraphics[width=2cm, height=1.10cm, valign=t,margin=0pt 3pt 0pt 0pt]{images/eie}
\hfill Pág.\thepage \\
\hline
\end{tabularx}      \\[-1pt]
\begin{tabularx}{\linewidth}{|>{\hsize=0.25\hsize}C
|>{\hsize=0.75\hsize}C|}
Author, ID\\
Author, ID\\
Author, ID}
& \makecell{Electromagnetismo I - I Ciclo 2018\\
-- Reporte Práctica Experimental 01}                   \\
\hline
\end{tabularx}%
}

\usepackage{blindtext}

\begin{document}
\pagestyle{fancy}
\blindtext[25]
\end{document}


in real document please remove graphicx's option demo.