Calculate Single-Ended and Coplanar Single-Ended Transmission Lines

This calculation type allows you to calculate the characteristic impedance and secondary parameters of a transmission line with specified geometric and electrophysical parameters.

Example

• Calculate Characteristic Impedance

Walkthrough

To perform a calculation of single-ended transmission lines, follow these steps:

1. Set the calculation settings as shown below:

   • Set Target to Transmission line
   • Set Target type to Single-ended or Coplanar single-ended
   • Set Mode to Lossless

   

2. Select the required transmission line model and review it in the preview area.

   

   Transmission line models with conductors on inner layers support the Trace inverted option. This option determines the position of the core (dielectric base) in the PCB stackup.

   

3. Define the input parameters for the target transmission line. The parameter set may vary depending on the selected transmission line model.

   For a single-ended transmission line, the parameter set includes:

   • H – Dielectric thickness. For each dielectric layer, you can specify its own thickness using the H1..H4 parameters (the number of H(n) parameters is determined by the number of dielectric layers).
   • Er – Dielectric constant. For each dielectric layer, you can specify its own dielectric constant using the Er1..Er4 parameters (the number of Er(n) parameters is determined by the number of dielectric layers).
   • W1 – Trace width.
   • W2 – Trace width after undercut.
   • T1 – Trace thickness.
   • C1 – Coating thickness.
   • CEr – Coating dielectric constant.

   

   For a coplanar single-ended transmission line, the parameter set also includes:

   • D1 – Distance from the trace to the reference plane.

   

4. Ensure Impedance is selected as the calculated parameter.

   

5. Click Calculate in the lower-right corner of the calculation tab to run the calculation.

   

   Before running the calculation, you can click the dropdown arrow next to the Calculate button to choose between two calculation saving options:

   

   • Overwrite calculation – Saves the modified input parameters to the current calculation, overwriting previous data.
   • Save as new calculation – Saves the modified input parameters to a new calculation. This calculation will appear in the Projects panel.

Calculation Results

The calculation results are displayed in a table at the bottom of the tab.

• Zo – Characteristic impedance (Ohm)
• Tpd – Propagation delay (ps/m)
• C – Capacitance per unit length (pF/m)
• Vp – Signal propagation velocity (m/s)
• L – Inductance per unit length (nH/m)
• EEr – Effective dielectric constant

See Also

• Example - Calculate Characteristic Impedance