Reducing the size won't help; assuming the standard settings for 10pt article on A4 paper, even at \scriptsize
the formula is too wide. With \tiny
it is not overfull, but it becomes unreadable.
A possibility is to avoid the radical, squaring the left hand side, and using multlined
from the mathtools
package for the numerator:
\documentclass[a4paper]{article}
\usepackage[T1]{fontenc}
\usepackage[utf8]{inputenc} % or other encoding
\usepackage[italian]{babel}
\usepackage{amsmath,mathtools}
\begin{document}
\begin{equation}
\lvert Y(j \omega) \rvert^2 =
\frac{
\begin{multlined}[b]
\omega^2 ( C\ped{DC} + C\ped{eq} )^2 \\
\qquad{} +\omega^4 [ ( R\ped{eq} C\ped{eq} C\ped{DC} )^2 -
2 (C\ped{DC} + C\ped{eq} ) ( L\ped{eq} C\ped{eq} C\ped{DC} ) ] \qquad\\
{} + \omega^6 ( L\ped{eq} C\ped{eq} C\ped{DC} )^2
\end{multlined}
}
{
1 + \omega^2 [ ( R\ped{eq} C\ped{eq} )^2 - 2 L\ped{eq} C\ped{eq} ] +
\omega^4 ( L\ped{eq} C\ped{eq} )^2
}.
\label{eq:cmut:abs_y_w_eq}
\end{equation}
\end{document}
The two \qquad
commands are just to widen the middle row which shouldn't be broken, but becomes the longest, spoiling the alignment.
Don't overuse \left
and \right
; in this formula none of them is needed.
A different strategy might be to use symbolic names for the coefficients: with the same preamble as before (but mathtools
is not necessary), you can write
\begin{align}
\lvert Y(j \omega) \rvert &=
\sqrt{
\frac{X_2 \omega^2 + X_4 \omega^4 + X_6 \omega^6}
{1 + Y_2 \omega^2 + Y_4 \omega^4}
},\\[2ex]
%%%
X_2 &= ( C\ped{DC} + C\ped{eq} )^2
\notag\\
X_4 &= ( R\ped{eq} C\ped{eq} C\ped{DC} )^2 -
2 (C\ped{DC} + C\ped{eq} ) ( L\ped{eq} C\ped{eq} C\ped{DC} )
\notag\\
X_6 &= ( L\ped{eq} C\ped{eq} C\ped{DC} )^2
\notag\\
Y_2 &= ( R\ped{eq} C\ped{eq} )^2 - 2 L\ped{eq} C\ped{eq}
\notag\\
Y_4 &= ( L\ped{eq} C\ped{eq} )^2
\notag
\end{align}
and get the following result
\ped
. I'm not sure whether that's a user defined macro or something else. Either way, I'm unfamiliar with it.article
on A4 paper, even at\scriptsize
the formula is too wide. With\tiny
it is not overfull, but it becomes unreadable.\ped
is not a standard command, but is only provided by theitalian
option tobabel
. So you see the necessity for a minimal working example (MWE)