Uniform Linear Array (ULA) Calculator
Compute beamwidth, directivity, array factor parameters, spacing constraints and grating lobe limits for a uniform linear antenna array.
Inputs
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ULA Diagram & Theory
Array Geometry
Key Equations
Wavelength: λ = c / f
Array Factor (AF):
AF(θ) = sin( N·ψ/2 ) / sin( ψ/2 )
ψ = (2π·d/λ)(cosθ − cosθ0)
HPBW (for uniform weights):
HPBW ≈ 50.8° / (N·d/λ)
Directivity:
D ≈ N (for isotropic elements)
First Side Lobe Level (uniform): ≈ −13.26 dB
Grating lobe condition:
d ≤ λ / (1 + |cosθ0|)
Symbol Glossary
- N – number of antenna elements
- d – element spacing
- θ0 – steering angle
- λ – wavelength
- AF – array factor
Notes
- Assumes **uniform weights** (no tapering).
- HPBW, directivity and SLL are approximate analytical formulas.
- Spacing beyond λ/2 can cause grating lobes when steering.