Modifying the Integral Equation Method
When using either the MoM or the MLFMM, you can specify the integral equation method to be applied to a face to obtain either faster iterative convergence or higher numerical accuracy.
 If the model is solved using the multilevel fast multipole method (MLFMM) activate the MLFMM.
 Select the face of the enclosed volume in the in the 3D view or in the details tree.

In the details tree, from the rightclick context menu, select Properties.
 On the Face properties dialog, click the Solution tab.

From the Integral equation
dropdown list, select one of the following options.

 Combined field

Solve the model using a combination of the electric field integral equation (EFIE) and magnetic field integral equation (MFIE) methods. This is known as the combined field integral equation (CFIE) method.

 Electric field
 Solve the model using the electric field integral equation (EFIE) method.

 Magnetic field
 Solve the model using the magnetic field integral equation (MFIE) method.
Note: The electric field integral equation (EFIE) is the default method and is valid for general open geometries. 
 Click OK to save the face properties and to close the dialog.