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Edge-Coupled Stripline Impedance Calculator

Welcome to our Edge-Coupled Stripline Impedance Calculator, your essential tool for calculating the impedance of edge-coupled striplines in PCBs based on specific operational parameters. This calculator is designed to provide accurate impedance assessments for various edge-coupled stripline configurations.

Click to learn more about the different types of traces.

Edge-coupled microstrips consist of two parallel traces that can effectively carry differential signals. This configuration helps reduce cross-talk and improves signal integrity in high-speed applications.

Inputs Required:

  • Trace Thickness (oz/ft², mils, cm, mm, µm, in)
  • Height (mils, cm, mm, µm, in)
  • Trace Width (mils, cm, mm, µm, in)
  • Trace Spacing (mils, cm, mm, µm, in)
  • Dielectric Constant

Outputs Provided:

  • Differential Impedance (Ohms)
  • Warnings for Values Exceeding Acceptable Ranges

PCB Design Calculators

Disclaimer: Please note that the results provided by this calculator are for estimation purposes only and should be used as a guide during the design process. We make every effort to ensure the accuracy of this tool, but it is important to verify all calculations through standard design verification processes. We are not liable for any errors in calculations or their consequences in your projects.
Diagram of a microstrip line to reference while using Edge-Coupled Stripline Impedance Calculator.
Inputs:
Trace Thickness (t)
Height (h)
Trace Width (w)
Trace Spacing (s)
Dielectric constant (εr)
Results:

*  This calculator determines the differential impedance of edge-coupled microstrips by considering crucial geometric dimensions such as trace width, trace thickness, height above the ground plane, and trace spacing. For accurate and reliable impedance calculations, it is essential that the ratio of the trace width ('w') to the height above the ground plane ('h') remains between 0.1 and 2.0. This range ensures proper confinement of the electromagnetic fields, which is critical for maintaining stable impedance and optimal signal integrity. Ratios outside this specified range might not comply with standard PCB design principles, potentially resulting in inaccurate impedance values and performance issues.

Edge-coupled microstrip transmission lines consist of two conductive traces running parallel on the same plane within a dielectric substrate, with a continuous ground plane on the opposite side. The impedance of an edge-coupled microstrip line depends on the width of each trace (w), the spacing between the traces (s), the thickness of the trace (t), the height above the ground plane (h), and the dielectric constant of the substrate (εr).

The calculator uses a specific formula to accurately estimate the impedance of your edge-coupled microstrip line:

  1. Logarithmic Function for Impedance Calculation:
    • Z0 = (60 / √(εr + 1.41)) × log((1.9 × (2 × h + t)) / (0.8 × w + t))
    • This function calculates the effective width of the coupled traces. It accounts for the increase in trace width due to the fringing fields, where the electric field lines spread out around the edges of the traces, effectively increasing their width.
  2. Square Root and Scaling Factors:
    • √(εr + 1.41)
    • This part of the formula helps approximate the effective dielectric constant, taking into account the non-ideal behaviors of the substrate material.
    • The scaling factor of 60 is used to align the result with the standard impedance units of Ohms. This factor helps balance the microstrip line's capacitive and inductive properties, ensuring your circuit meets its required performance characteristics.

While using our Edge-Coupled Stripline Impedance Calculator, remember that complex PCB designs often require expert guidance. If you need additional support, our team at 911EDA is ready to assist with comprehensive PCB design services and engineering solutionsLeverage our expertise in PCB design and electronic engineering to enhance your project's success. Learn more about our services and how we can help bring your ideas to life by visiting our PCB Design Services and Engineering Services pages.

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