Antenna Length Calculator Formula

Understand the math behind the antenna length calculator. Each variable explained with a worked example.

Use the Antenna Length Calculator

Formulas Used

Full Wavelength

full_wavelength_m = wavelength_m

Half-Wave Dipole

half_wave_cm = wavelength_m / 2 * 100

Quarter-Wave Monopole

quarter_wave_cm = wavelength_m / 4 * 100

Variables

VariableDescriptionDefault
frequency_mhzFrequency(MHz)433
wavelength_mDerived value= 299.792 / frequency_mhzcalculated

How It Works

Antenna Length

Formulas

Wavelength = c / f = 299.792 / f(MHz) meters

Half-wave dipole = wavelength / 2

Quarter-wave monopole = wavelength / 4

In practice, antennas are shortened 2-5% due to end effects and conductor diameter.

Worked Example

Design an antenna for 433 MHz ISM band.

frequency_mhz = 433
  1. 01Wavelength = 299.792 / 433 = 0.6924 m
  2. 02Half-wave dipole = 0.6924 / 2 = 34.62 cm
  3. 03Quarter-wave = 0.6924 / 4 = 17.31 cm

Ready to run the numbers?

Open Antenna Length Calculator