Dipole Antenna Calculator

How to Use This Calculator

This calculator helps you design a half-wave dipole antenna by calculating its resonant frequency, total length, and bandwidth based on either the frequency or wavelength you provide.

Input Parameters

• Frequency (MHz): Enter the operating frequency of your antenna in megahertz (MHz).
• Wavelength (m): Enter the wavelength of your operating frequency in meters.
• Conductor Material: Select the material of the antenna conductor (affects impedance but not physical dimensions for half-wave dipoles).

Calculation Results

• Resonant Frequency: The frequency at which the antenna is resonant (equal to the input frequency).
• Total Length: The total length of the antenna (for a half-wave dipole, this is λ/2).
• Half Element Length: The length of each half of the dipole element.
• Bandwidth (2Δf): The frequency range within which the antenna operates effectively, typically ±0.1λ from the resonant frequency.
• Bandwidth (±0.1λ): An alternative bandwidth calculation based on ±0.1 wavelength.

Antenna Principles

A half-wave dipole antenna is one of the most common and versatile antenna designs. It consists of two identical elements spaced a quarter-wavelength apart, fed at their center point. At its resonant frequency, the impedance of a half-wave dipole is approximately 73 ohms resistive.

The resonant frequency (f) of a half-wave dipole is related to the wavelength (λ) by the formula:

f = c / λ

Where c is the speed of light (approximately 3×10⁸ meters per second).

The total length of a half-wave dipole antenna is equal to half the wavelength at the operating frequency:

Total Length = λ / 2

The bandwidth of a dipole antenna is typically narrow, with most of the energy being radiated perpendicular to the plane of the antenna. The bandwidth is often specified as the frequency range within which the antenna's impedance stays within ±10% of its resonant value.