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RayRF | Free RF calculators

Guided Wavelength Calculator (lambda_g, Bulk and Microstrip)

Guided wavelength in a bulk dielectric or microstrip. lambda_g = lambda_0 / sqrt(eeff). Microstrip eeff via Hammerstad-Jensen, bulk via straight epsilon_r.

Guided Wavelength Calculator

The wavelength of a wave traveling through a dielectric or microstrip is shorter than in free space. lambda_g = lambda_0 / sqrt(eeff).

Units
Length
Frequency

Inputs

GHz
λg = 58.335 mmeeff = 4.400 | v = c/sqrt(eeff)
Wavelength in dielectric (lambda_g)
Guided wavelength lambda_g
58.335mm
2296.65 mil

More

Effective eeff4.400
lambda_0 (vacuum)122.364 mm
lambda_g / 229.167 mm
lambda_g / 414.584 mm

Analytical calculation

Every step the calculator runs, with the formula, your numbers plugged in, and the result.

Free-space wavelength
Effective permittivity
Bulk dielectric, so eeff = er.
Guided wavelength
Wave slows by sqrt(eeff).

Frequently asked

Why is wavelength shorter in dielectric?

The wave slows by sqrt(er) because part of its energy is stored in polarizing the dielectric. Same time period, slower speed, so shorter wavelength.

References

  • Bulk dielectriclambda_g = lambda_0 / sqrt(eps_r). Standard kinematic relation for a homogeneous medium.
  • Microstrip eeffHammerstad, E. & Jensen, O. 1980 (microstrip effective permittivity, used when Medium = Microstrip).
  • ConceptEffective permittivity (overview)

Closed-form is just the start.

These calculators hand you the analytical starting point. RayRF takes you the rest of the way: antennas, filters, feedlines, and more, simulated on your real stackup with copper losses, dielectric loss, and finite ground. Roughly a second per iteration.

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