Enter your Trace Width (W), Trace Thickness (T), Substrate Height (H), and Dielectric Constant (εr) into the Stripline Impedance Calculator to find your PCB trace's Characteristic Impedance, along with Capacitance per Unit Length and key geometry ratios like W/(H-T) and T/H.
Characteristic Impedance
--
Capacitance per Unit Length
--
W/(H-T) Ratio
--
T/H Ratio
--
A stripline is a flat conductor embedded between two parallel ground planes, typically used in multilayer PCBs. The trace is completely surrounded by dielectric material and reference planes, providing excellent signal isolation and controlled impedance.
Analytical formulas work best when W/(H-T) < 0.35 and T/H < 0.25. For very thin or wide traces outside these ranges, the calculator may deviate significantly from actual values. Field solvers provide more accurate results for complex geometries.
Higher dielectric constant (εr) reduces the characteristic impedance. Common PCB materials like FR-4 have εr around 4.0-4.5, while high-frequency materials like Rogers can range from 2.2 to 10.
The required trace width depends on substrate height, thickness, and dielectric constant. For typical FR-4 (εr=4.0) with 15 mil substrate height and 1.37 mil thickness, approximately 10-12 mil width achieves 50 ohms.
Use stripline when you need better signal isolation, reduced crosstalk, and symmetric field distribution. Stripline provides better EMI shielding but requires more PCB layers compared to microstrip.
Common conversions: 1 mil = 0.0254 mm, 1 inch = 1000 mils = 25.4 mm. Most PCB design tools work in mils for trace dimensions, but metric units are also widely used in modern designs.
Symmetric stripline has equal spacing to both ground planes, while asymmetric stripline has unequal spacing. This calculator assumes symmetric configuration where the trace is centered between the planes.