Calculator Inputs
Plotly Graph
This graph shows wavelength change with dielectric constant at the current frequency and magnetic permeability.
Example Data Table
| Material | Frequency (GHz) | εr | μr | Free-Space λ (m) | Dielectric λ (m) | Velocity (m/s) |
|---|---|---|---|---|---|---|
| Air | 2.4 | 1.0006 | 1 | 0.124914 | 0.124876 | 299702560.71 |
| PTFE | 2.4 | 2.1 | 1 | 0.124914 | 0.086199 | 206876450.22 |
| Polyethylene | 2.4 | 2.25 | 1 | 0.124914 | 0.083276 | 199861638.67 |
| Quartz | 2.4 | 3.8 | 1 | 0.124914 | 0.064079 | 153790286.01 |
| Glass | 2.4 | 5.5 | 1 | 0.124914 | 0.053263 | 127831933.61 |
| Alumina | 2.4 | 9.8 | 1 | 0.124914 | 0.039902 | 95765187.89 |
Formula Used
n = √(εr × μr) v = c / n λ0 = c / f λd = λ0 / n = v / f k = 2π / λd Phase shift = (path length / λd) × 360°This calculator assumes a lossless or low-loss medium for wavelength estimation. It converts your chosen units, computes refractive index, then finds phase velocity, dielectric wavelength, wavenumber, electrical length, and path phase shift from the selected material model.
How to Use This Calculator
- Choose a calculation mode: material constants, refractive index, or known free-space wavelength.
- Enter frequency or wavelength in your preferred unit.
- Provide dielectric properties using εr and μr, or enter refractive index directly.
- Enter path length to estimate electrical length, transit time, and phase shift.
- Click the calculate button to show results above the form, beneath the header section.
- Review the graph and example table to compare wavelength behavior across dielectric values.
- Use the CSV or PDF buttons to export the current result summary.
Frequently Asked Questions
1. What is dielectric wavelength?
Dielectric wavelength is the distance one wave cycle occupies inside a material. It is shorter than free-space wavelength because electromagnetic waves travel slower in most dielectric media.
2. How do I calculate wavelength in a dielectric?
Find the refractive index first. For many materials, n = √(εrμr). Then divide free-space wavelength by n. You can also calculate it directly from λ = v/f after finding phase velocity.
3. Why does wavelength decrease inside a dielectric?
The frequency set by the source stays constant at boundaries, but wave speed decreases in the medium. Since wavelength equals speed divided by frequency, the wavelength becomes smaller.
4. Does frequency change when a wave enters a dielectric?
No. Frequency remains the same across the boundary for a continuous source. The medium mainly changes wave velocity and wavelength, not the oscillation rate of the source.
5. What role does relative permeability play?
Relative permeability affects refractive index through n = √(εrμr). In many nonmagnetic dielectrics, μr is close to 1, so permittivity dominates the wavelength change.
6. What is electrical length?
Electrical length tells you how many wavelengths fit within a path. It is useful for transmission lines, resonators, antennas, and phase-sensitive layouts in high-frequency design.
7. Can this calculator be used for RF and microwave work?
Yes. It is useful for quick RF, microwave, and photonics estimates where you need wavelength, phase velocity, or phase shift inside a dielectric medium.
8. Is this result exact for lossy materials?
Not always. Strongly lossy materials require complex permittivity and propagation constants. This tool provides a practical wavelength estimate for lossless or lightly lossy media.