Stackup and materials

The stackup is the ordered set of layers that gives your board its vertical structure and its material properties. This page covers the layer model, the dielectric and conductor properties, and where they are edited. Drawing copper and placing ports is Geometry and drawing.

The layer model

A layer is one of three types:

• Conductor carries the copper you draw on it. It is a zero-thickness sheet at a single Z, not a solid slab. The drawn shapes on that layer become the metal.
• Dielectric is a substrate slab with a thickness, a relative permittivity, and a loss tangent. It fills the gap between the conductors above and below it.
• Air is a free-space spacer. It has a thickness so it sets a gap, but no permittivity or loss. It emits nothing to the mesh, so the gap simulates as air.

Layers are ordered top to bottom in the Stackup list, topmost first. Each layer's Z is derived, never typed: the bottom layer sits at z = 0 and every layer above it stacks up by the dielectric and air thicknesses below it. A conductor's own thickness does not move any Z, only dielectric and air thicknesses do. Because Z is computed, the z field in the properties panel is read only. Change a dielectric thickness and every layer above it shifts.

A new blank project starts with no layers. Build the stackup by adding layers, or open the bundled example to start from a working one.

Adding, removing, and ordering layers

The Stackup section holds the layer list and two buttons:

• New Layer opens a dialog. Pick the type (Conductor, Dielectric, or Air), give it a unique name, and for a dielectric enter the thickness and relative permittivity. The new layer lands at the top of the stack.
• Delete Selected removes the selected layer.

Drag a row in the list to reorder it. Right-click a row for Properties, Rename, Copy Layer Above, Copy Layer Below, and Delete. Double-click a row to open its properties.

The active layer is the one new geometry is drawn on. Click a row to make it active, or press a digit key 1 to 9 on the Edit tab to select that row by position.

The Viewport view-mode selector sets which layers are drawn on the canvas. All Layers shows everything, Focused highlights the active layer and dims the rest, and Active Only shows only the active layer's geometry. Shift+S cycles the three modes.

Dielectric properties

Selecting a layer with nothing else selected shows the Layer Properties panel: the name, the derived z, and the material fields for that layer type. The right-click Properties... dialog holds the same fields and works while the panel is hidden by another selection.

A dielectric layer carries a thickness in mm, a relative permittivity epsilon_r (at least 1), and a loss tangent (0 for lossless). Higher permittivity slows propagation and shortens the guided wavelength, so it sets the electrical length of traces and the resonant frequencies.

A preset fills these values:

Editing any value switches the preset to Custom.

Conductors

A conductor layer carries the copper you draw on it as a zero-thickness sheet at that layer's Z. At export the drawn shapes rasterize onto that plane as a perfect electric conductor: a lossless metal with no thickness and no per-layer material fields to set. A new conductor layer needs only a name.

Paint every dielectric, or it simulates as air

A dielectric layer with no geometry painted on it is treated as air and its permittivity is ignored. validate and running a simulation both warn on this, since running a layer as air is sometimes intended. If the layer is a real substrate, paint a board-sized rectangle across it so it carries its permittivity. If it is left over from an earlier stackup, delete it. A layer at epsilon_r = 1 is not flagged, since painting it would change nothing.

Layer limit on Hobby

The Hobby plan allows a stackup of up to 3 layers total, counting conductors and dielectrics together. Pro and Founding plans have no layer limit.