Explore field patterns using dipoles, arrays, and apertures. Tune spacing and phase quickly. Generate plots and exports for cleaner engineering decisions.
Sample values for a simple sin(θ) reference cut, normalized to 1.00 at 90°.
| θ (deg) | Magnitude (norm) | Power (dB) |
|---|---|---|
| 0 | 0.0000 | -60.00 |
| 30 | 0.4330 | -7.27 |
| 60 | 0.8660 | -1.25 |
| 90 | 1.0000 | 0.00 |
| 120 | 0.8660 | -1.25 |
| 150 | 0.4330 | -7.27 |
| 180 | 0.0000 | -60.00 |
Every run generates a normalized elevation cut from θ = 0° to 180°. The angular step sets the sample count; a 1° step yields 181 points, Normalization divides each magnitude by the peak value, then converts to decibels using P(dB) = 20·log10(|E|n). Values are clamped at −60 dB to keep tables readable when nulls approach numerical floors.
The short dipole uses |E(θ)| = |sinθ|, producing a broad maximum at 90°. The half‑wave dipole uses |cos((π/2)cosθ)/sinθ|, which slightly sharpens the main lobe and deepens nulls at 0° and 180°. These curves are useful baselines before adding array gain.
For the ULA, the array factor is AF = |sin(Nψ/2)/(N·sin(ψ/2))| with ψ = k·d·cosθ + β. Increasing N narrows the main beam; doubling N roughly halves beamwidth for similar spacing. Spacing near d/λ = 0.5 limits grating lobes, while larger spacing can create additional peaks. Progressive phase β steers the maximum roughly toward cosθ0 ≈ −β/(k·d) when |β| is modest.
The calculator estimates HPBW by locating the first −3 dB crossings around the peak angle. Because crossings depend on sampling, smaller θ steps give more accurate HPBW for narrow beams. It also reports front‑to‑back as the maximum level in 0°–90° minus the maximum level in 90°–180°. These metrics help compare directionality across designs with consistent normalization.
The rectangular aperture option uses an E‑plane cut of |sinc(k·a·sinθ/2)|, assuming uniform illumination. As frequency increases (smaller λ, larger k), the main lobe tightens and sidelobes become more visible. Larger physical aperture a produces narrower beams, matching common microwave antenna behavior. Parameter b is included for completeness, but this cut assumes φ = 0°, so b does not change the plotted slice.
CSV export delivers θ, normalized magnitude, and dB columns for spreadsheet post‑processing, curve fitting, or overlay comparisons. PDF export provides a compact summary and sample points for quick reviews and approvals. Use the Polar plot for lobe shape and the Cartesian plot for reading beamwidth and sidelobe levels accurately. When comparing revisions, keep frequency and θ step identical so exported numbers remain directly comparable.
Magnitudes are divided by the maximum value in the computed cut. This makes the peak equal to 1.000, so different antenna sizes and configurations can be compared on the same scale.
Deep nulls can drop far below typical plot ranges and clutter the table. Clamping improves readability while preserving main‑lobe, beamwidth, and sidelobe trends.
Adjust the progressive phase β. For many broadside-style arrays, small β values shift the peak away from 90°. Keep spacing near 0.5λ to avoid grating lobes while steering.
No. It computes a 2D elevation cut versus θ. Use full-wave simulation or measured data for complete 3D patterns, polarization, and mutual-coupling effects.
Use 1° for narrow beams or report-quality tables. Use 3°–5° for quick exploration. Smaller steps produce more points and slightly better HPBW estimates.
Yes. The CSV includes θ (degrees), normalized magnitude, and dB. Most spreadsheet tools import it cleanly, letting you overlay multiple exports on one chart.
Important Note: All the Calculators listed in this site are for educational purpose only and we do not guarentee the accuracy of results. Please do consult with other sources as well.