Fresnel Zone Calculator
Calculate Fresnel zone radius, clearance requirements, and obstacle position for wireless and microwave links.
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Inputs
Live
Math
3
Related
Enter parameters and click Calculate to view results
Formula & Theory
r₁ = 17.32 × √(d₁×d₂ /(fGHz×(d₁+d₂)))This formula is used to calculate antenna parameters for fresnel zone calculator.
Overview
Fresnel Zone helps you calculate design values for a link budget & rf project from Frequency, Distance to Obstacle, Distance from Obstacle. Calculate Fresnel zone radius, clearance requirements, and obstacle position for wireless and microwave links. Use the result to make an informed first design decision before choosing hardware, setting dimensions, or evaluating the RF system in its final environment.
Input Guide
Enter Frequency, Distance to Obstacle, Distance from Obstacle exactly in the units shown by this fresnel zone. Check the operating band, unit prefix, and decimal position before calculating; these are the inputs used by the formula.
- Frequency — use GHz.
- Distance to Obstacle — use km.
- Distance from Obstacle — use km.
Output Guide
The results describe the calculated fresnel zone values for the inputs you entered. Check each value against the available space, selected components, feed system, and operating conditions before making a final design decision.
How This Calculator Works
The Fresnel Zone uses r₁ = 17.32 × √(d₁×d₂ /(fGHz×(d₁+d₂))). Supply Frequency (GHz), Distance to Obstacle (km), Distance from Obstacle (km) in the displayed units, then use the calculated values as the first engineering target for this link budget & rf design or analysis.
Design Notes
This link budget & rf calculation is based on r₁ = 17.32 × √(d₁×d₂ /(fGHz×(d₁+d₂))). Real-world accuracy depends on factors such as material properties, losses, mounting, nearby conductors, ground interaction, feed-line effects, and construction tolerance. Confirm the final system with measurement or simulation.
Build and Tuning Notes
Apply the fresnel zone result as an initial target, then validate it in the intended installation. Keep the physical layout and feed arrangement consistent while testing, change one parameter at a time, and record the measured outcome before making another adjustment.
Frequently Asked Questions
What does the Fresnel Zone calculate?
Calculate Fresnel zone radius, clearance requirements, and obstacle position for wireless and microwave links. The calculation provides an initial design value based on Frequency (GHz), Distance to Obstacle (km), Distance from Obstacle (km).
Which inputs are needed for the Fresnel Zone?
Enter Frequency (GHz), Distance to Obstacle (km), Distance from Obstacle (km) using the displayed units. Each value directly affects the calculated result, so confirm the unit and operating conditions before running the calculation.
How accurate is this fresnel zone?
It follows r₁ = 17.32 × √(d₁×d₂ /(fGHz×(d₁+d₂))). It is accurate for the formula assumptions, but installed performance can change because of materials, loss, environment, mounting, nearby objects, and measurement uncertainty.
What should I do after using the Fresnel Zone?
Compare the result with the practical constraints of your link budget & rf system, then validate the completed design with appropriate measurement equipment or simulation.
Alex Warren
B.Sc. in Electrical & Electronic Engineering (EEE)
Alex specialises in antenna design and wave propagation. His expertise helps ensure these calculators present practical RF concepts, useful design estimates, and clear engineering guidance for students, HAM operators, and wireless professionals.