Cloverleaf Antenna Calculator
Calculate wavelength, element dimensions, and operating parameters for a circularly polarized cloverleaf antenna.
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Inputs
Live
Math
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Related
Enter parameters and click Calculate to view results
Formula & Theory
λ = c/f, Element Length ≈ λ/4This formula is used to calculate antenna parameters for cloverleaf antenna calculator.
Overview
The Cloverleaf Antenna Calculator determines wire element lengths, individual leaf lobe dimensions, and feed parameters for 3-leaf circularly polarized cloverleaf antennas. Highly popular in FPV (First-Person View) drone video systems (5.8 GHz, 2.4 GHz, and 1.2 GHz), the cloverleaf antenna provides omnidirectional coverage with excellent multipath signal rejection.
Input Guide
Enter Frequency exactly in the units shown by this cloverleaf antenna. Check the operating band, unit prefix, and decimal position before calculating; these are the inputs used by the formula.
- Frequency — use MHz.
Output Guide
The results describe the calculated cloverleaf antenna 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 Cloverleaf Antenna uses λ = c/f, Element Length ≈ λ/4. Supply Frequency (MHz) in the displayed units, then use the calculated values as the first engineering target for this resonant antennas design or analysis.
Design Notes
A cloverleaf antenna consists of three identical wire loops tilted at $45^{\circ}$ relative to the horizontal plane and spaced $120^{\circ}$ apart around a central coaxial feed. Each loop consists of a full wavelength wire bent into a specific geometry (a $1/4\lambda$ vertical leg, a $1/2\lambda$ outer arc, and a $1/4\lambda$ ground leg), yielding a total perimeter of approximately $1\lambda$. Tilting the lobes generates Circular Polarization (RHCP or LHCP depending on the direction of leaf slant), which significantly minimizes video flicker caused by multipath reflections.
Build and Tuning Notes
For optimal $50\;\Omega$ feedpoint impedance matching and low VSWR ($<1.2:1$), maintain an exact $45^{\circ}$ tilt angle for all three leaves. Use rigid enamel-coated copper or brass wire (typically 0.8 mm to 1.2 mm diameter) to prevent physical deformation during drone flights. Validate antenna resonance and axial ratio using a Vector Network Analyzer (VNA). Pair a 3-leaf Cloverleaf transmitter antenna with a 4-leaf Skew-Planar Wheel receiver antenna for maximum link robustness.
Frequently Asked Questions
Why are Cloverleaf Antennas widely used in FPV drone video links?
Cloverleaf antennas provide omnidirectional Circular Polarization (CP). Unlike linear dipole antennas, circular polarization rejects multipath reflections (signals bouncing off walls, trees, or ground), preserving a clean video feed even during aggressive acrobatic maneuvers.
What determines whether a Cloverleaf is RHCP or LHCP?
Polarization (Right-Hand Circular Polarization - RHCP vs. Left-Hand Circular Polarization - LHCP) is determined by the tilt direction of the leaves. Slanting leaves to the right yields RHCP, while slanting to the left yields LHCP. Transmitter and receiver antennas must match polarization.
What is the difference between a 3-leaf Cloverleaf and a 4-leaf Skew-Planar Wheel?
A 3-leaf cloverleaf offers a closer match to $50\;\Omega$ input impedance, making it ideal for video transmitters (VTX). A 4-leaf skew-planar wheel offers a superior axial ratio and multipath rejection, making it preferable for video receivers (VRX).
Why is a 45-degree tilt angle required for each leaf?
Tilting each lobe at $45^{\circ}$ balances horizontal and vertical electric field components in phase quadrature ($90^{\circ}$ shift), creating a circular rotating wave with a near-unity axial ratio.
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.