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Antenna Effective Aperture Calculator
Calculators / Antenna Aperture
Antenna Effective
Aperture Calculator
Calculate the effective aperture Ae of any antenna using the fundamental RF engineering formula Ae = λ² G / (4π). Also solves for gain from aperture, computes aperture efficiency, and compares physical vs effective capture area. Essential for RF link budget and antenna selection.
Effective Aperture (Ae)
Physical Aperture (A)
⚙ Effective Aperture Engine
λ = — cm
0 dBi = isotropic. Dipole = 2.15 dBi
Physical cross-section of the antenna
Used when solving for G from Ae
Advanced Parameters
Uniform illumination=1.0, typical dish=0.55–0.70
Ohmic loss reduces effective aperture. % (100=lossless)
Reduces effective Ae by polarisation mismatch factor
W/m²
Pr = Pd × Ae (received power at antenna terminal)
Calculated Results
Effective Aperture (Ae)
—cm²
Aperture efficiency (Ae / A)
— %
Ae (m²)—
Ae (cm²)—
Gain (dBi)—
Gain (linear)—
Wavelength (λ)—
λ² / (4π)—
Physical Aperture (A)—
Aperture efficiency (ηap)—
Received Power (Pr)—
Gain (dBd)—
Enter values above to calculate.
📖 Theory
Every antenna — regardless of its physical size or type — has an effective aperture Ae: the equivalent capture area that intercepts incoming power from a plane wave.
Core Formula
Ae = λ² G / (4π)
λ = free-space wavelength, G = linear gain
Received Power
Pr = Pd × Ae
Pd = incident power density (W/m²). This is the Friis equation in aperture form.
Aperture Efficiency
ηap = Ae / A
A = physical aperture area. ηap < 1 always. Uniform illumination → ηap = 1 (max). Typical dish ≈ 0.55–0.70.
Key Insight
An isotropic antenna (G=1, 0 dBi) has Ae = λ²/4π. A dipole (2.15 dBi) has Ae = 0.13λ². A 30 dBi dish at 10 GHz has Ae ≈ 0.24 m² despite a physical size of ~0.4 m². That is aperture efficiency.
📡 Aperture vs Gain Viewer
Live Simulation
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◉ Ae scales with gain and frequency
Chart Type
Gain
10 dBi
−540 dBi
Frequency
2.4 GHz
0.1 GHz30 GHz
Ae vs Gain
ℹ
RF Engineer Insights
Enter antenna gain and frequency to see effective aperture insights.
Common Applications
RF Link Budgets
Received power Pr = Pd × Ae. Effective aperture connects antenna gain directly to received power in any link budget calculation.
Satellite Earth Stations
Compare effective aperture of dish antennas for uplink/downlink. Larger Ae → more received power from the satellite.
Radar System Design
Radar range equation uses transmit gain and receive effective aperture. Larger Ae improves target detection sensitivity.
Antenna Comparison
Compare a small patch (low Ae) vs a dish (high Ae) at the same frequency. Ae reveals the true capture capability of any antenna.
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