Waveguides.md

+<table>
+  <tr>
+    <th colspan="2">Metallic waveguides</th>
+  </tr>
+  <tr>
+    <td style="text-align:center"><img src="Waveguides_screenshot1.png" width=100%></td>
+    <td style="text-align:center"><img src="Waveguides_screenshot2.png" width=100%></td>
+  </tr>
+  <tr>
+    <th colspan="2"> Browse <a href="https://gitlab.onelab.info/doc/models/tree/master/Waveguides/">model files</a></th>
+  </tr>
+</table>
+
+## Quick start
+
+To run the model, open `main.pro` with Gmsh.
+
+## Additional information
+
+This model explores the behavior of metallic waveguides. Various shapes are
+predefined, both in 2D and 3D.
+
+----
+*Model developed by @modave, Benjamin Klein and @geuzaine*