Calculadora de Comprimento de Antena
Calcule o comprimento ideal da antena para uma frequência de operação específica.
Half-Wave Dipole
34.62 cm
Half-Wave Dipole vs Frequency
Formula
## 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.
Exemplo Resolvido
Design an antenna for 433 MHz ISM band.
- 01Wavelength = 299.792 / 433 = 0.6924 m
- 02Half-wave dipole = 0.6924 / 2 = 34.62 cm
- 03Quarter-wave = 0.6924 / 4 = 17.31 cm
Perguntas Frequentes
Why does size matter?
An antenna resonates when its length matches a fraction of the wavelength. Off-resonance antennas have poor efficiency and high VSWR.
What about PCB antennas?
PCB trace antennas are physically shorter due to the substrate dielectric constant. Multiply by velocity factor (typically 0.6-0.8).
Half-wave vs quarter-wave?
Half-wave dipoles are balanced and need a balun. Quarter-wave monopoles need a ground plane but are simpler and half the size.
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