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Wavelength Calculator
Calculators / RF Wavelength
RF Wavelength
Calculator
The fundamental equation of RF engineering: λ = c / f. Calculate wavelength from frequency, or frequency from wavelength — for antenna design, RF engineering, and microwave systems. Covers the full spectrum from ELF to mmWave.
RF Spectrum Position
ELF/VLFAMHFVHFUHFSHFmmWave
⚙ Wavelength Engine
Enter frequency to calculate wavelength
Enter wavelength to calculate frequency
λ in medium = λ₀ / √εr
1.0 = free space. Coax ≈ 0.66–0.85. Overrides medium if <1.0
Advanced Parameters
λ_medium = λ₀ / √εr. Overrides medium selector
°C
Speed of sound in air: c_sound ≈ 331 + 0.6T m/s
m/s
Default: 299,792,458 m/s (exact, NIST)
Total length = n × λ (useful for array design)
Calculated Results
Free-space Wavelength (λ₀)
—m
λ in medium—
Frequency—
λ/2 (half-wave)—
λ/4 (quarter-wave)—
λ in mm—
λ in cm—
λ in inches—
λ in feet—
n × λ (total)—
RF Band—
Period (T = 1/f)—
Wave number (k)—
Enter frequency above to calculate.
📖 Theory
The wavelength is the distance between two consecutive peaks (or any two identical points) of an electromagnetic wave. It is inversely proportional to frequency.
Free-space Formula
λ = c / f
c = 299,792,458 m/s (speed of light), f = frequency in Hz
In a Medium
λ_medium = λ₀ / √εr
λ_medium = λ₀ × k
εr = relative permittivity, k = velocity factor (0–1)
Antenna Length Rule
λ/2 dipole: L ≈ 143/f(MHz) m
λ/4 monopole: L ≈ 71.5/f(MHz) m
Includes VF=0.95 and end-effect corrections.
The wave number k = 2π/λ describes spatial frequency. The period T = 1/f is the time for one complete cycle. Both are fundamental in EM field analysis and transmission line theory.
📡 Wavelength & Spectrum Viewer
Live Simulation
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◉ Wave scales with frequency & medium
Display Mode
Frequency
144 MHz
Medium εr
1.0
Air (1.0)Alumina (12)
Sine Wave (E-field)
ℹ
Wavelength Insights
Enter a frequency above to see wavelength insights.
Common Applications
Antenna Design
Every antenna element length — dipole, monopole, Yagi, patch — is a fraction of λ. Wavelength is the starting point of all antenna design.
RF Engineering
Transmission line stubs, matching networks, quarter-wave transformers, and waveguide cutoff frequencies all depend on λ at the operating frequency.
Microwave Systems
At GHz frequencies, wavelengths are millimetres. PCB trace lengths, via spacing, and component placement all interact with the signal wavelength.
Education
The λ = c/f equation is the most fundamental relationship in RF and electromagnetic engineering — the first equation every RF engineer learns.
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