Antenna Gain Calculator
An Interactive Calculator and Learning Center
Parabolic Antenna Gain Calculator
Instantly calculate the theoretical gain of a parabolic (dish) antenna. Enter your parameters below.
Calculated Antenna Gain
42.2 dBi
Formula Used
This is the theoretical maximum forward gain relative to an isotropic antenna. Real-world performance may vary.
What Does It All Mean?
Antenna gain isn't about creating energy; it's about focusing it. Here's a breakdown of the key concepts that determine your antenna's performance.
Antenna Gain
A measure of an antenna's ability to direct or concentrate radio frequency energy in a particular direction. It's like focusing a flashlight beam—the tighter the beam, the brighter the light (and the higher the gain).
dBi vs. dBd
dBi: Gain compared to a theoretical isotropic antenna, which radiates energy equally in all directions (like a perfect sphere). This is the most common industry standard.
dBd: Gain compared to a half-wave dipole antenna. A simple conversion: dBi ≈ dBd + 2.15.
Efficiency (η)
Represents how much of the electrical power delivered to the antenna is actually radiated. Losses due to materials, design, and construction reduce efficiency. A typical parabolic dish has an efficiency of 50-60%.
Visualize the Impact of Parameters
See for yourself how changing a single parameter affects antenna gain. This helps build an intuitive understanding of antenna design principles.
Frequently Asked Questions
What is considered a "high" antenna gain?
"High gain" is relative to the application. For Wi-Fi, 8-15 dBi is high. For satellite communication, gains can exceed 50 dBi. Higher gain means a more focused beam, which requires more precise aiming.
How can I increase my antenna's gain?
Based on the formula, there are two primary ways: increase the antenna's physical size (diameter) or increase the operating frequency. Improving efficiency through better design and materials also helps, but often with diminishing returns.
Does antenna gain increase my transmitter's power?
No. Antenna gain does not add power. It focuses the existing power from the transmitter into a narrower beam. The total radiated power remains the same, but the power in the desired direction, known as Effective Isotropic Radiated Power (EIRP), increases.
Is more gain always better?
Not necessarily. Very high gain antennas have very narrow beamwidths, making them difficult to aim and susceptible to signal loss from slight movements. The best antenna has a gain and beamwidth appropriate for the specific application, balancing signal strength with coverage area and ease of use.
