Defining a Unit Cell

Define a layered unit cell using layers of substrate, free space and metal.

1. On the Periodic Structures tab, in the Structure group, select  Unit Cell.

   
   

   

   
   Figure 1. The Create Unit Cell dialog.

2. From the Reference Vector drop-down list, select one of the following:
   • To specify the skew angle relative to the U axis, select U vector.
   • To specify the skew angle relative to the V axis, select V vector.
3. Under Dimensions, specify dimensions and orientation of the unit cell:
   1. In the Skew angle ( $\theta$ ) field, specify the unit cell skew angle.
      Tip: A skew angle of 0 degrees yields a rectangular unit cell.
   2. In the Distance (U) field, specify the unit cell dimension in the U axis direction.
   3. In the Distance (V) field, specify the unit cell dimension in the V axis direction.
4. For each layer:
   1. From the Method drop-down list, select one of the following:
      • To specify a layer of substrate (dielectric) or vacuum (Free space), select Substrate.
      • To specify a layer of metal, select Metal or Aperture.
      Tip: A Metal layer realises the shape exactly. An Aperture layer realises a metallic layer minus the shape.
   2. For a layer of substrate, specify the following:
      • In the Medium field, specify the dielectric medium or Free space for vacuum.
      • In the Thickness field, specify the thickness of the layer.
   3. For a layer of metal (Metal or Aperture), specify the following:
      • In the Shape field, specify the shape to be used.
      • In the Rotation field, specify the rotation of the shape.
      • [Optional] To specify a thickness, select the Define thickness check box and in the Thickness field specify the metal thickness.
        Tip: Specifying thickness creates a 3D layer of metal.
5. In the Z-value at the top of layer 1 field, specify the Z axis position of the top of layer 1.
6. Click OK to define the unit cell and to close the dialog.