Setting Lambda Refinement

Lambda refinement is the process of refining the initial mesh based on the material-dependent wavelength. It is recommended and selected by default.

HFSS performs solution-adaptive mesh refinement to produce accurate results. Lambda Refinement is necessary to avoid false convergence and achieve accuracy to the field data, especially for electrically large problems (approximately greater than 2*lambda). The Lambda refinement process helps simulation start with the optimal balance between element count and element size. For efficient convergence, the initial mesh should meet some element electrical size requirements determined by lambda refinement. Typically, a few elements per wavelength are needed for accurate results. Because wavelength depends upon the material, the element length target differs for each material. You can specify the size of the element target by which HFSS refines the mesh in the Lambda Target field or select the recommended Use Default Value. The default value in the Lambda Target field also depends upon the order of the basis functions. For example, if the lambda target is 0.3333, the initial mesh is refined such that on each solid the length of the elements are approximately smaller than 0.333*wavelength. Lambda refinement stops if the input mesh already reaches the Lambda refinement target.

If you use the Advanced tab to link to a mesh from another design or project, Do Lambda Refinement is unchanged.

To specify the size of the target value by which HFSS will refine the mesh:

1. From the Solution Setup window, select the Options tab and enable Do Lambda Refinement.

   This enables the Target field and the Use free space lambda check box. It also enables Lambda refinement from the background material for the IE solver. See: IE Solver Options area on the Advanced tab.

2. In the Target field, enter a value for the wavelength or accept the default.

   The Target defaults depend on the Order of Basis function selections. For example, for Driven solutions and a First Order basis function, the default target is 0.3333, which means that HFSS will refine the mesh until most element lengths are approximately one-third wavelength.

   For Eigenmode solutions and a First Order basis function, the default target is 0.2

   If you change the Order of Basis functions in the Solution Setup window, the default changes automatically. Setting the Order of Basis affects the default value of the lambda refinement in the solution setups as follows.

   Zero order:	driven 0.1	eigenmode 0.1
   First order:	driven 0.3333	eigenmode 0.2 (as is)
   Second order:	driven 0.6667	eigenmode 0.4
   Mixed order	driven 0.6667	eigenmode 0.6667

3. If you want the initial mesh to be refined based on the wavelength in free space, select Use free space lambda. Material-dependent lambda refinement will be deactivated.
   Note:

   Changing the Lambda refinement target invalidates any solutions that were performed with the previous lambda refinement.

   If an object is highly conductive, very little energy will penetrate into it, so it does not need a dense mesh. In such cases, free space mesh is applied.