Please enter all required values.
RESULTS
Input Parameters Specification
Wire DiameterRound conductor diameter used in the wire stripline impedance equation. A larger diameter usually lowers impedance.
Substrate HeightDistance between the wire conductor region and reference plane geometry. Height strongly affects calculated impedance.
Dielectric ConstantRelative permittivity of the PCB dielectric material. Higher dielectric constant generally lowers impedance.
OutputCharacteristic impedance in ohms for RF PCB and transmission line design checks.
Practical Operational Examples
RF Interconnect
Estimate impedance for round wire style stripline structures in RF layouts.
Stackup Check
Change wire diameter, dielectric height or material Er to tune impedance.
Controlled Impedance
Use this when a round conductor or wire-like stripline structure is used inside a dielectric region.
Material Comparison
Compare FR4, PTFE, ceramic or other dielectric constants to understand impedance movement.
Diagrams & Theory
A wire stripline uses a round conductor inside a dielectric region with reference planes. Impedance depends strongly on conductor diameter, height and dielectric constant.
Formulas & Mathematical Logic
Formula used from source code: Z0 = 377 / (2 × π × sqrt(Er)) × log(4 × H / (π × D))
Where D = wire diameter, H = substrate height, and Er = dielectric constant.
Selected diameter and height units are converted using the original source multipliers before calculation.
Practical meaning: larger wire diameter usually reduces impedance, while larger height usually increases impedance.
Step-by-Step Example
Example: wire diameter = 10 mil, substrate height = 60 mil, dielectric constant = 4.2.
The calculator converts wire diameter and substrate height using the selected unit multipliers.
The dielectric constant is used inside the square-root term.
The ratio 4 × H / (π × D) is calculated.
The natural log of that ratio is multiplied by 377 / (2 × π × sqrt(Er)).
The final characteristic impedance is displayed in ohms.
How to Use This Calculator
Enter wire diameter and select the correct unit.
Enter substrate height and select its unit.
Enter dielectric constant of the PCB or dielectric material.
Click Calculate to get wire stripline impedance.
Compare the result with your RF or transmission line impedance target.
About This Calculator
Estimate impedance for round-wire stripline transmission structures.
The CalcBoy Wire Stripline Impedance Calculator calculates characteristic impedance using wire diameter, substrate height and dielectric constant.
Wire stripline impedance is useful when a round conductor is modeled inside a dielectric region with reference planes. This type of calculation can appear in RF interconnects, embedded wire structures, transmission line experiments, fixture design and special PCB geometry checks where a flat copper trace formula is not the best fit.
The result depends strongly on the conductor diameter and dielectric height. Increasing wire diameter usually lowers impedance because the conductor becomes electrically larger. Increasing the spacing to reference planes usually raises impedance. Dielectric constant also matters because a higher-permittivity material slows the wave and reduces impedance.
This calculator is intended for quick engineering estimation. For critical RF, microwave, controlled-impedance or production designs, confirm with field solver data, PCB manufacturer stack-up information, test coupons or measured impedance.
Best UseRound-wire stripline impedance estimates for RF and transmission line work.
Supported InputsWire diameter, substrate height and dielectric constant.
Helpful ForRF fixtures, embedded wire geometry, controlled impedance and lab prototypes.
Design ReminderUse real dielectric data for better impedance accuracy.
Tip: For precision RF design, impedance depends on the complete field geometry. Use this as a fast estimate, then validate with measurement or simulation.
Frequently Asked Questions
What is wire stripline impedance?
It is the characteristic impedance of a round conductor placed in a dielectric region with reference plane geometry.
What inputs are required?
The calculator needs wire diameter, substrate height and dielectric constant.
Does larger wire diameter lower impedance?
Generally yes. A larger conductor diameter lowers the calculated impedance in this equation.
Why does dielectric constant matter?
Higher dielectric constant reduces wave velocity and usually lowers characteristic impedance.
Can I use this for PCB production design?
Use it as an estimate. For production controlled impedance, verify with manufacturer stack-up or field solver data.
What unit is the output?
The output impedance is displayed in ohms.
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