\documentclass[11pt]{article}
\usepackage{fig4tex}
\begin{document}

% 1. Definition of characteristic points

\figinit{.8cm,orthogonal}

%Axes.
\figpt 1:(0,0,0)
\figpt 2:(2,0,0)
\figpt 3:(0,2,0)
\figpt 4:(0,0,2)
\figvectC 0 (0,6,0)
\figpttra 1:=1 /1, 0/
\figpttra 2:$x$=2 /1, 0/
\figpttra 3:$y$=3 /1, 0/
\figpttra 4:$z$=4 /1, 0/

%Antenne.
\def\ray{2}
\def\hau{3}

\figpt 5:(0,-\ray,-\hau)
\figpt 6:(0,0,-\hau)
\figpt 7:(0,\ray,-\hau)
\figpt 8:(\ray,0,-\hau)
\figpt 9:(-\ray,0,-\hau)

\figpt 10:(0,-\ray,\hau)
\figpt 11:(0,0,\hau)
\figpt 12:(0,\ray,\hau)
\figpt 13:(\ray,0,\hau)
\figpt 14:(-\ray,0,\hau)

% 2. Creation of the graphical file

\def\ROTA{10}
\figset projection(longitude=\ROTA)
\figdrawbegin{}

%Axes.
\figdrawarrow[1,2]
\figdrawarrow[1,3]
\figdrawarrow[1,4]

%Anneau du bas.
\figdrawarccircP 6;\ray[5,8,8]
\figset (dash={7})
\figdrawarccircP 6;\ray[5,9,9]
\figset (dash={1})

%Anneau du haut.
\figdrawarccircP 11;\ray[12,13,13]
\figdrawarccircP 11;\ray[12,14,14]

%Courant.
\figset arrowhead(fillmode=yes)
\figdrawarrowcirc 6,7,8 ; \ray (0,90)
\figset (dash={7})
\figdrawarrowcirc 6,7,9 ; \ray (0,90)
\figset (dash={1})

\figset arrowhead(fillmode=yes)
\figdrawarrowcirc 11,10,13 ; \ray (0,90)
\figdrawarrowcirc 11,10,14 ; \ray (0,90)

%Brins verticaux (en tenant compte de la rotation due a l'angle de vue).
\figvectC 100(0,0,1)
\figptrot 5:=5/6,\ROTA,100/\figptrot 10:=10/6,\ROTA,100/
\figptrot 7:=7/6,\ROTA,100/\figptrot 12:=12/6,\ROTA,100/
\figdrawline[5,10]
\figdrawline[7,12]

%Courant sur les brins verticaux.
\figptbary 15:[5,10;1,1]
\figptbary 16:[7,12;1,1]
\figdrawarrow[5,15]
\figdrawarrow[12,16]

\figdrawend

% 3. Writing text on the figure

\def\dist{3pt}
\figvisu{\figBoxA}{{\sc Fig. 6}\ --\ L'antenne \'el\'ementaire pour $k$ impair}{%
\figwritew 2:(\dist)
\figwritene 3:(\dist)
\figwriten 4:(\dist)
\figwritew 10:$A$(\dist)
\figwritee 12:$B$(\dist)
\figwriten 8:$I/2$(\dist)
\figwriten 9:$I/2$(\dist)
\figwriten 13:$I/2$(\dist)
\figwriten 14:$I/2$(\dist)
\figwritew 15:$I$(\dist)
\figwritee 16:$I$(\dist)
}
\box\figBoxA
\end{document}