Home
Back
Quarter Wave Antenna Formula:
| From: | To: |
A ground plane antenna is a type of antenna that uses a flat conducting surface as a simulated ground. It's commonly used in vertical monopole antenna designs where the ground plane serves as a reflector, creating an image of the antenna element.
The calculator uses the quarter-wave antenna formula:
Where:
Explanation: The formula calculates the optimal length for a quarter-wave antenna based on the operating frequency. The velocity factor accounts for signal propagation speed in different materials.
Details: Proper antenna length is crucial for optimal signal transmission and reception. An incorrectly sized antenna will have poor efficiency, high SWR (Standing Wave Ratio), and reduced performance.
Tips: Enter the operating frequency in Hz. For more accurate results, include the velocity factor if your antenna uses a dielectric material other than air (typical values: 0.66-0.95 for coaxial cables, 0.85-0.95 for insulated wire).
Q1: What is a quarter-wave antenna?
A: A quarter-wave antenna is a type of monopole antenna that is one quarter of the wavelength of the frequency it's designed to transmit or receive.
Q2: Why is the ground plane important?
A: The ground plane creates an electrical mirror image of the antenna, effectively making it work like a half-wave dipole antenna with improved radiation pattern.
Q3: What is velocity factor?
A: Velocity factor is the ratio of the speed at which a radio wave travels in a material compared to the speed of light in a vacuum. Different materials have different velocity factors.
Q4: Can I use this calculator for other antenna types?
A: This calculator is specifically designed for quarter-wave ground plane antennas. Other antenna types (half-wave, full-wave) require different calculations.
Q5: How accurate is this calculation?
A: The calculation provides a theoretical length. Actual construction may require slight adjustments for optimal performance due to various factors like nearby objects and exact material properties.