Physics and mechanics
Electromagnetic Wave Solver Calculator
Solve frequency, wavelength, or relative permittivity for a lossless electromagnetic plane wave and report phase speed, intrinsic impedance, period, and phase constant.
CURRENT MODEL
Enter the declared physical case
RF students, antenna teams, cable and dielectric test engineers, and educators checking a homogeneous-medium plane-wave state before detailed field or transmission-line analysis.
LIVE PHYSICAL ANALYSIS
Orthogonal fields and propagation in the declared medium
The live sketch labels current wavelength, phase speed, and intrinsic impedance without pretending to solve boundaries or attenuation.
| Quantity | Symbol or expression | Current value | Unit |
|---|
How to use
Solve one wave variable in one declared medium
- Select frequency, wavelength, or relative permittivity as the unknown; the corresponding field is disabled.
- Enter frequency in MHz or wavelength in meters for the same phase-wave state.
- Enter positive real relative permittivity and permeability for a homogeneous lossless medium.
- Read the solved quantity together with phase speed and intrinsic impedance; they are coupled by the constitutive assumptions.
- Inspect period and phase constant before transferring the result into antenna, material, or propagation work.
- Use the f lambda residual to verify the wave relation before copying or exporting the current solution.
Plane-wave fundamentals
Five ideas behind the medium solution
- Source frequency
- The temporal oscillation rate, which remains continuous across a stationary material interface.
- Phase wavelength
- The distance between equal carrier phases in the declared medium, equal to phase speed divided by frequency.
- Relative permittivity
- The positive real electric constitutive ratio used by this ideal lossless model.
- Relative permeability
- The corresponding magnetic constitutive ratio, retained explicitly even when near unity.
- Intrinsic impedance
- The E/H ratio of a uniform traveling plane wave, not a device terminal impedance.
Calculation method
Close the constitutive and kinematic equations together
The medium first sets v_p = c0/sqrt(epsilon_r mu_r). The selected unknown is then solved from v_p = f lambda, or relative permittivity is inferred from measured frequency and phase wavelength. Period and phase constant follow from the solved state.
Intrinsic impedance is calculated independently as eta0 sqrt(mu_r/epsilon_r). The final residual compares f lambda with the constitutive phase speed so unit or input wiring errors cannot hide behind a plausible wavelength.
Bulk medium versus interface
The solver describes propagation after a uniform plane wave exists inside one medium. Reflection coefficient, refraction angle, polarization boundary conditions, and transmitted amplitude require interface data.
Phase speed versus signal speed
In the declared nondispersive model the phase and group speeds coincide. Real dielectric properties vary with frequency, so pulse delay requires frequency-dependent complex material data.
Impedance is not antenna matching
Intrinsic impedance relates local E and H fields in an unbounded medium. Antenna feed impedance also includes geometry, radiation, reactance, nearby objects, and frequency-dependent current distribution.
Detailed calculation process
Symbols, current substitution, intermediate quantities, and reconciliation
| Symbol | Meaning | Default | Unit |
|---|---|---|---|
| c0 | Exact vacuum speed of light | 299792458 | m/s |
| f | Temporal frequency | 100 | MHz |
| lambda | Medium phase wavelength | solved | m |
| epsilon_r | Relative permittivity | 4 | 1 |
| mu_r | Relative permeability | 1 | 1 |
| eta0 | Vacuum wave impedance | 376.730314 | ohm |
Waiting for valid inputs.
Evidence to retain
Keep the material state with the solved wave
Record specimen identity, lot and orientation, temperature, moisture, frequency, measurement fixture and calibration, extracted complex permittivity and permeability when available, uncertainty, sample thickness, interface assumptions, and whether the reported wavelength is measured phase wavelength or inferred from nominal material data.
Scope and limitations
Where the lossless plane-wave model stops
- No conductivity, dielectric loss tangent, magnetic loss, attenuation constant, or complex impedance
- No dispersion, anisotropy, nonlinearity, plasma, negative-index, or resonant constitutive behavior
- No interface reflection, refraction, polarization conversion, or multilayer interference
- No waveguide cutoff, cable modes, antenna near field, or cavity boundaries
- No field amplitude, Poynting power, photon energy, or exposure limit calculation
- No material certification from a single inferred relative-permittivity value
The solver describes a uniform plane wave in a linear, homogeneous, isotropic, lossless, nondispersive medium with positive real relative permittivity and permeability. It does not model conductivity, complex material parameters, waveguides, plasma cutoffs, interfaces, or group delay.
Key terminology
Electromagnetic-wave glossary
- Plane wave
- An ideal field with constant phase over planes transverse to propagation.
- Phase speed
- The speed at which a fixed phase point travels through the medium.
- Phase constant
- The phase change in radians per meter, equal to 2 pi divided by wavelength.
- Constitutive parameter
- A material property linking electric or magnetic flux density to its corresponding field.
- Intrinsic impedance
- The field ratio E/H for a traveling plane wave in the bulk medium.
- Dispersion
- Frequency dependence of propagation parameters that can separate phase and group velocities.
Practical cases
Two solutions with different engineering consequences
Dielectric wavelength estimate
An RF lab enters 100 MHz and epsilon_r = 4 for a preliminary nonmagnetic sample. The wavelength halves relative to vacuum and intrinsic impedance also changes, alerting the team that fixture dimensions and field ratios cannot use vacuum values.
Permittivity from phase measurement
A materials team measures phase wavelength at a known frequency and solves epsilon_r under mu_r = 1. They retain sample thickness and uncertainty, then compare with a complex calibrated extraction because conductor loss and fixture interfaces are excluded here.
Important note
A bulk-wave solution is a model checkpoint
Use measured complex material data and the correct electromagnetic boundary solver for RF safety, high-power design, antenna matching, waveguides, multilayers, or certification. A clean f lambda result does not validate the assumed constitutive model.
Frequently asked questions
Why is electromagnetic wave speed lower in a dielectric?
In this ideal model, phase speed is c0 divided by sqrt(epsilon_r mu_r). The material polarization and magnetization response changes the propagation relation while frequency remains set by the source.
Does frequency change when a wave enters another medium?
At a stationary interface the temporal frequency is continuous. Phase speed and wavelength change; reflection and refraction require boundary conditions beyond this bulk solver.
What is intrinsic impedance?
It is the electric-to-magnetic field ratio E/H for a uniform traveling plane wave in the declared medium. It is not automatically the input impedance of an antenna, cable, or waveguide.
Can the calculator solve a lossy material with conductivity?
No. Loss makes permittivity, propagation constant, and impedance complex and frequency dependent. Use a complex-wave or transmission-line model with conductivity and branch conventions.
Why can relative permeability differ from one?
Magnetic materials can have a frequency-dependent permeability. Many ordinary dielectrics are near mu_r = 1, but the solver keeps the parameter explicit rather than silently assuming it.
Is the solved relative permittivity a material certification?
No. It is the positive real value implied by the entered phase wavelength and frequency under an ideal homogeneous lossless model. Measurement fixture effects, dispersion, anisotropy, and uncertainty remain outside scope.
Authority and follow-on work
Reliable sources and related calculators
- NIST Fundamental Physical ConstantsProvides SI context for the vacuum speed of light and electromagnetic constants.
- NIST 2018 CODATA Recommended ValuesLists c0 = 299,792,458 m/s as an exact defining constant.
- MIT OpenCourseWare 6.013 ElectromagneticsCovers uniform plane waves, constitutive properties, propagation, and wave impedance.
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