Antenna Gain Calculator

Summary

Calculate antenna gain in dBi and dBd from physical aperture area, aperture efficiency, and operating frequency.

How it works

1. Enter the physical aperture area of the antenna in square meters.
2. Enter the aperture efficiency (0–100%). Typical values: parabolic dish 55–75%, horn 50–90%.
3. Enter the operating frequency in MHz or GHz.
4. The tool computes wavelength λ = c / f, then gain G = η × 4π × A / λ².
5. Gain is converted to dBi = 10 × log₁₀(G) and dBd = dBi − 2.15.
6. The effective aperture and half-power beamwidth (HPBW estimate) are also shown.

Use cases

• Sizing parabolic dish antennas for satellite or microwave links.
• Verifying datasheet gain figures for horn or aperture antennas.
• Budgeting link margins in point-to-point RF design.
• Teaching RF and electromagnetics in university labs.
• Comparing different aperture sizes at the same frequency.
• Estimating beamwidth to plan sectorization in cellular networks.
• Validating simulation results from HFSS or CST against analytical formulas.
• Quick sanity checks during telecom equipment procurement.

Frequently Asked Questions