Basis Functions in HFSS

Various interpolation schemes, or basis functions, can be used to interpolate field values from nodal values.

• A first order tangential element basis function interpolates field values from both nodal values at vertices and on edges.

First order tangential elements have 20 unknowns per tetrahedron.

• A zero order basis function makes use of nodal values at vertices only — and therefore assumes that the field varies linearly inside each tetrahedron.

Zero order tangential elements have six unknowns per tetrahedron.

• A second order tangential element interpolates field values from nodal values at vertices, on edges and on faces.

Second order tangential elements have 45 unknowns per tetrahedron.

• Mixed order assigns basis function elements based on the need for higher accuracy in different parts of the model.