Calculation method and supported range
λ₀ = c/f; λg = c/(f√εeff); phase = 360° × length/λg; propagation delay = length × √εeff/c. c = 299,792,458 m/s.
Assumes a lossless, nondispersive line with 1 ≤ εeff ≤ 128. Phase is unwrapped; delay is propagation delay, not a dispersive group-delay prediction. Frequency input: 10⁻⁹–1,000 GHz.
Technical sources
Using the result
Use effective permittivity from the transmission-line model rather than inserting bulk laminate Dk into a microstrip calculation. A phase result is unwrapped: more than one full cycle can accumulate on a long line. Material and geometry dispersion can change both phase and group delay.
From a calculation to a released design
Keep the input assumptions with the result. Recalculate when the ordered material, dielectric height, copper or operating conditions change. Confirm the final construction with the fabricator and use field simulation or measurement wherever the simplified model omits an important effect.
See the controlled-impedance guide and material selection workflow for the next checks.