How do I specify the loss of a dielectric layer?

You specify the loss of a dielectric layer by entering the dielectric parameters for each layer. It is possible to define a different loss, i.e. a different dielectric, for each layer in your circuit. These parameters are entered in the Dielectric Editor dialog box. You access this dialog box by selecting Circuit => Dielectric Layers from the project editor main menu and clicking on the Above, Below or Edit button in the Dielectric Layers dialog box which appears on your display.

The Global dielectric library, supplied with your software installation, contains common dielectrics and their loss parameters.

The following parameters are used to define a dielectric layer:

• thickness (Thickness)

• relative dielectric constant (Erel)

• dielectric loss tangent (Dielectric Loss Tan)

• dielectric conductivity (Diel Cond)

• relative magnetic permeability (Mrel)

• magnetic loss tangent (Ma Loss Tan)

The dielectric constant and loss of a dielectric layer are defined as follows:

• Erel: The ratio (e’/e_o´), where e is the real part of the permittivity of the dielectric layer material, and e_o is the permittivity of free space. The ratio is dimensionless.

• Loss Tan: The ratio (e´´/e), where e = e - je´´, and e is the complex permittivity of the dielectric layer material. The ratio is dimensionless.

• Diel. Cond: The quantity s, where s is the dielectric conductivity in Siemens per meter.

The EM Analysis engine combines the Loss Tan and Diel Cond to determine the total dielectric loss. Although the loss of a dielectric can contain contributions from both terms, many dielectric vendors only publish data for one term or the other, whichever dominates the loss.

For a detailed discussion of dielectric loss, please see the ''Metalization and Dielectric Layer Loss'' chapter in the Sonnet User's Guide. The user's manuals are available in PDF format in PDF format by selecting Help => Manuals from any Sonnet application.