Stay Updated with Antenna Design Insights
Subscribe to receive practical antenna design tips, RF simulation techniques, and insights on high-performance wireless systems.
Antenna Gain Calculator
Calculators / Antenna Gain
Antenna Gain
Calculator
Calculate antenna gain vs directivity, effective aperture, and radiation efficiency. Convert between dBi and dBd, calculate from physical aperture or beamwidth, and understand the relationship between gain, directivity and ohmic losses.
Gain Lobe
Isotropic Reference
Efficiency η
⚙ Antenna Gain Engine
λ = — cm
D = G / η. For lossless antenna D = G
Ratio of radiated power to accepted power
Physical capture area of the antenna
Uniform illum. ≈ 1.0, typical reflector ≈ 0.55–0.70
°
Half-power (−3 dB) beamwidth in elevation plane
°
Half-power beamwidth in azimuth plane
Advanced Parameters
Ω
η = Rr / (Rr + Rl). 0 = ideal lossless
Ω
Dipole ≈ 73 Ω, monopole ≈ 36.5 Ω
dB
Impedance mismatch loss (SWR 1:1 = 0 dB)
Effective gain reduction from polarisation mismatch
Calculated Results
Antenna Gain (G)
—dBi
Radiation Efficiency (η)
— %
Gain (dBi)—
Gain (dBd)—
Directivity (D)—
Gain (linear)—
Effective Aperture (Ae)—
Physical Aperture (A)—
Aperture efficiency (ηap)—
Effective loss (ohmic)—
Total system loss—
Wavelength (λ)—
Enter values to calculate.
📖 Theory
Antenna gain, directivity, and efficiency are three related but distinct quantities that describe how well an antenna concentrates radiated energy in a given direction.
Gain vs Directivity
G = η × D
G(dBi) = D(dBi) + 10·log(η)
G ≤ D always. G = D only when η = 1 (lossless).
Effective Aperture
Ae = G × λ² / (4π)
Ae = ηap × A (aperture antennas)
Every antenna has an effective capture area proportional to its gain.
Gain from Beamwidth
D ≈ 32,400 / (θ_E × θ_H)
G ≈ 29,000 / (θ_E × θ_H)
θ in degrees. Kraus approximation for pencil-beam antennas.
Efficiency from Resistance
η = Rr / (Rr + Rl)
η(dB) = 10·log₁₀(η)
Rr = radiation resistance, Rl = ohmic loss resistance.
📡 Gain & Aperture Viewer
Live Simulation
|
◉ Pattern & Ae scale with gain and efficiency
Display
Gain
6.0 dBi
−540 dBi
Efficiency
90%
10%100%
Radiation Pattern
ℹ
Design Insights
Select antenna type or enter gain/directivity values to see design insights.
Common Applications
Link Budget Design
Antenna gain is the key input to the Friis equation — critical for calculating received power, range, and link margin in any RF system.
Antenna Selection
Compare gain and effective aperture of different antenna types — dipole, patch, Yagi, horn, dish — for the same frequency.
Antenna Measurement
Convert measured beamwidths to gain, verify antenna efficiency from radiation resistance, or cross-check dBi vs dBd readings.
Satellite & Radar
Calculate dish antenna gain, effective aperture, and aperture efficiency for earth station, satellite, and radar system design.
Stay Updated with RF & Antenna Insights
Get practical antenna design tips, simulation techniques, and RF engineering insights directly in your inbox.