This converter makes it possible to determine the width of a microstrip track from a target characteristic impedance Z0, the trace thickness (t), the dielectric thickness (H) and the relative dielectric constant (εr). It provides a quick method to convert electrical specifications into physical dimensions of the microstrip line.
Formula
W = (7.48 × H) / exp(Z0 × √(εr + 1.41) / 87) − 1.25 × t
Explanation of the formula
The formula uses the relative dielectric constant εr to calculate the effective capacitance of the line. The exponential in the denominator adjusts the width according to the target impedance Z0, while the subtractive term 1.25 × t takes into account the physical thickness of the trace. The final result W corresponds to the width necessary to obtain the desired impedance.
Uses
- Accurately size microstrip lines for high frequency PCBs.
- Quickly convert impedance requirements into physical values for manufacturing.
- Evaluate the impact of variations in H, t or εr on the final impedance.
- Facilitate RF design and signal integrity calculations in printed circuit boards.