HFSS15: Assigning Master Boundaries

Master and slave boundaries enable you to model planes of periodicity where the E-field at every point on the slave boundary surface is forced to match the E-field of every corresponding point on the master boundary surface to within a phase difference. The transformation used to map the E-field from the master to the slave is determined by specifying a coordinate system on both the master and slave boundaries.

To assign a Master boundary:

1. Select a surface on which to assign the boundary and click HFSS>Boundaries>Assign>Master to bring up the Master Boundary dialog box.

2. You must specify the coordinate system in the plane on which the boundary exists. First draw the U vector of the coordinate system. HFSS uses the U vector that you draw and the normal vector of the boundary face to calculate the Vvector. If necessary, you can reverse the direction of the V vector.

a. Select New Vector from the U Vector pull-down list.

The Master Boundary dialog box disappears while you draw the U vector.

b. Select the U vector’s origin, which must be on the boundary’s surface, either by:

• Clicking the point for the vector origin.

• Typing the point’s coordinates in the X, Y, and Z boxes.

c. Select a point on the u-axis to indicate the U vector direction.

The Master Boundary dialog box reappears and the model display shows the U vector and V vector as red and blue arrows respectively.

d. If you need to reverse the direction of the V vector, select Reverse Direction.

HFSS will compute the E-field on this boundary and map it to the slave boundary using the transformation defined by the master and slave coordinate systems.