This simulator circles an animated scanning probe around a transmitting dipole. Rotate the antenna, compare short and half-wave dipole patterns, and measure how direction, distance and polarization mismatch change the far-field signal received by an idealized unity-gain probe.
• A real-time 3D scene of a center-fed dipole and insulating hub, a coaxial feed/balun/transmitter, a normalized far-field power envelope, a scanning receiving probe, a rotation stage with angular guide frame, and outward energy markers, with home view, focus-selected-part, auto-rotate, expand and show/hide labels controls. • Ten experiment controls: dipole model (thin half-wave or electrically short), frequency (100–1,000 MHz), accepted transmitter power (1–100 W), radiation efficiency (0.1–1), antenna tilt (0–90°), probe polar angle (0–180°), probe starting azimuth (0–360°), probe azimuth scan rate (0–45°/s), physical far-field distance (5–100 m) and receive polarization mismatch (0–90°). • Live metrics: peak directivity, peak gain in dBi, probe direction normalized power, relative pattern in dB, far-field power density, unity-gain reference received power, total radiated power, current probe azimuth, probe angle from antenna axis, modeled dipole length and free-space wavelength. • Playback controls: pause/resume, advance 1 s, advance 5 s, and four playback speeds. • A Curves & measurements tab with two live charts (antenna-axis elevation cut and range/received power), the full directivity and gain equations, and snapshot measurement readouts. • An Experiments tab with four guided fixtures (azimuthal symmetry, sweep through nulls, compare a short dipole, cross-polarized reception) and a Model verification bench that runs independent deterministic checks, plus a timestamped event log and a copyable trial report. • A Learn & assess tab with four guided lessons, a knowledge-check quiz with reset, and a written model-scope statement with a technical-background reference link.
The 3D envelope plots normalized radiated power in each direction, not a physical object or propagating wavefront — a dipole has maximum radiation broadside to its axis and a null exactly along its axis. Directivity measures how concentrated the radiation is relative to the average over all directions, while gain also folds in radiation efficiency: increasing loss reduces gain and radiated power without changing the normalized pattern shape in this model.
Tilting the dipole changes which world directions land on strong lobes versus deep nulls, since the probe moves in world coordinates while the pattern itself follows the antenna axis.
Far-field power density falls as 1/r², so doubling distance quarters the power density reaching the probe. The reference receiver uses unity gain and an effective aperture of λ²/(4π); a linear polarization mismatch multiplies received power by cos²ψ — this is an imposed test condition, not an orientation solved for the visible probe hardware.
This is an analytical isolated thin-dipole far field in free space, using either an electrically short or half-wave sinusoidal-current model. It excludes ground reflection, multipath, mutual coupling, impedance tuning, receiver sensitivity and near-field solutions. The axial pattern null is exactly zero, so dB display is unavailable exactly on-axis, and all offered distances lie beyond the simple far-field bound for the modeled arms.
No. Its horizontal azimuth cut is uniform, meaning it radiates the same in every compass direction at a fixed elevation, but radiation vanishes exactly along the vertical antenna axis itself.
Directivity measures how concentrated radiated power is relative to an isotropic radiator, using only the pattern shape. Gain multiplies directivity by radiation efficiency, so a lossier antenna has lower gain than directivity even with an identical normalized pattern.
It falls to one quarter. The same total radiated power spreads over a spherical area proportional to distance squared, so power density follows an inverse-square law.
The electrically short dipole has directivity 1.5, while the half-wave dipole has directivity about 1.641 (about 2.15 dBi at unit efficiency). The short-dipole elevation lobe is slightly broader than the half-wave pattern.