Parabolic Dish Antenna Gain (dBi) & Half-Power Beamwidth (HPBW°) Calculator

Compute dish antenna gain (dBi) and 3 dB beamwidth (deg) from dish diameter and frequency.

Parabolic Dish Gain
41.36 dBi
Half-Power (−3 dB) Beamwidth (HPBW) 1.46 degrees
Effective Capture Aperture Area (A_e) 0.68 m²
Diameter-to-Wavelength Ratio (D / λ) 48.03 wavelengths
Inputs
⚡ Scenarios:
m
Parabolic dish reflector diameter D in meters.
GHz
Operating frequency in GHz (e.g., 5.8 GHz, 12 GHz Ku-band, 28 GHz Ka-band).
η
Aperture illumination efficiency η (typically 0.55 to 0.70).
Results & Graph
Parabolic Dish Gain
41.36 dBi
Half-Power (−3 dB) Beamwidth (HPBW)
1.46 degrees
Effective Capture Aperture Area (A_e)
0.68 m²
Diameter-to-Wavelength Ratio (D / λ)
48.03 wavelengths

Parabolic Dish Gain

Graph 1 • Parabolic Dish Gain & Beamwidth • Domain Architecture & Live Telemetry Maps Dish Diameter Meters, Operating Frequency Ghz, Aperture Efficiency Eta through Parabolic Dish Gain & Beamwidth Formula.
Source / Tx Target / Rx Parabolic Dish Gain & Beamwidth Propagation Path Parabolic Dish Gain 41.36 dBi Half-Power (−3 dB) Beamwid: 1.46 degrees Effective Capture Aperture: 0.68 m²
Graph 2 • Parabolic Dish Gain Across Dish Diameter Meters Sweep (40% → 160%) Evaluates Gain (dBi) = 10 × log₁₀[ η × (π × D / λ)² ]; HPBW_deg ≈ 70 × (λ / D) across 7 operating points (current input highlighted).
0 dBi 24.99 dBi 49.98 dBi 33.40 0.480m 36.92 0.720m 39.42 0.960m 41.36 1.20m 42.94 1.44m 44.28 1.68m 45.44 1.92m
Graph 3 • Joint Sensitivity: Dish Diameter Meters × Operating Frequency Ghz Compares Parabolic Dish Gain when Operating Frequency Ghz is shifted +25% (solid) vs. −25% (dashed).
0 dBi 25.06 dBi 50.13 dBi --- Operating Frequency Ghz @ 75% 40.20 -30% 41.88 -15% 43.29 +0% 44.51 +15% 45.57 +30%
Summary: A 1.2 m dish at 12 GHz (λ = 2.5 cm, η = 0.6) achieves 41.36 dBi directional gain and a narrow 1.46° Half-Power Beamwidth.
Summary: A 1.2 m dish at 12 GHz (λ = 2.5 cm, η = 0.6) achieves 41.36 dBi directional gain and a narrow 1.46° Half-Power Beamwidth.
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Formula & Mathematical Methodology: Parabolic Dish Gain & Beamwidth Formula

Gain (dBi) = 10 × log₁₀[ η × (π × D / λ)² ]
HPBWdeg ≈ 70 × (λ / D)
Gain (dBi) = 10 × log₁₀[ η × (π × D / λ)² ]; HPBW_deg ≈ 70 × (λ / D)
  • dishDiameterMeters: Dish Diameter Meters (m)
  • operatingFrequencyGhz: Operating Frequency Ghz (GHz)
  • apertureEfficiencyEta: Aperture Efficiency Eta (η)

Rounding: Engineering outputs round to 2–3 decimal places; discrete material bag/unit counts round up via ceiling.

Worked Example: Engineering Scenario: Parabolic Dish Gain & Beamwidth

Compute dish antenna gain (dBi) and 3 dB beamwidth (deg) from dish diameter and frequency.

  1. Enter your system dimensions, electrical/RF ratings, or environmental conditions.
  2. Evaluate the governing equation: Gain (dBi) = 10 × log₁₀[ η × (π × D / λ)² ]; HPBW_deg ≈ 70 × (λ / D).
  3. Inspect the primary design output, supporting allowances, and 3 SVG schematics.
Result: Computes Parabolic Dish Gain & Beamwidth via Gain (dBi) = 10 × log₁₀[ η × (π × D / λ)² ]; HPBW_deg ≈ 70 × (λ / D).

Frequently Asked Questions

How does the Parabolic Dish Antenna Gain (dBi) & Half-Power Beamwidth (HPBW°) Calculator calculate results?

It evaluates Gain (dBi) = 10 × log₁₀[ η × (π × D / λ)² ]; HPBW_deg ≈ 70 × (λ / D) directly in your browser and updates three custom SVG visualizations in real time.

Can I use Goal Seek to solve backwards for a required dimension or rating?

Yes. Click "🎯 Goal Seek" in the results toolbar to solve backwards for any numeric input parameter.

Does this engineering calculator work offline?

Yes. All calculations run 100% locally in your browser and work offline via the CalculatorGraph PWA.

Science & Engineering · RF, Telecom & Antenna Engineering

Parabolic Dish Antenna Gain (dBi) & Half-Power Beamwidth (HPBW°) Calculator: inputs, method, and how to read the result

Compute dish antenna gain (dBi) and 3 dB beamwidth (deg) from dish diameter and frequency.

Choose inputs for the case you are checking

The defaults are illustrative. Replace them with values for your case and keep the units shown beside each field.

  • Dish Diameter Meters: Parabolic dish reflector diameter D in meters.
  • Operating Frequency Ghz: Operating frequency in GHz (e.g., 5.8 GHz, 12 GHz Ku-band, 28 GHz Ka-band).
  • Aperture Efficiency Eta: Aperture illumination efficiency η (typically 0.55 to 0.70).

What the calculation includes

With the default values shown, Parabolic Dish Gain is 41.36 dBi. The calculation follows Parabolic Dish Gain & Beamwidth Formula; the formula and variable definitions above show how the inputs combine.

One-input check: With the other defaults held constant, changing Dish Diameter Meters from 1.2 m to 1.32 m changes Parabolic Dish Gain from 41.36 dBi to 42.18 dBi. This is a comparison inside the calculator's stated model, not a prediction.

Where to use caution

  • Uses standard NREL, IEEE, ASHRAE, and IRC design equations.
  • Verify final structural, electrical, and mechanical specifications against local building codes.

Scope: Global Engineering & Building Code Standard Check the assumptions and limitations against your situation before relying on the estimate.

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