GridBeam

Patch antenna array & multi-beamforming

3D radiation pattern

drag to rotate

u-v space

click / drag = steer the active beam

Array excitation

hue = phase · opacity = amplitude

Radiated field — vertical cut

Pattern cut

normalised to the maximum

Guide

Getting started in 30 seconds

  1. Pick a scenario at the top right, or set the number of elements and the array spacing.
  2. Click in the u-v map to steer the active beam. Add more beams with “+ Add a beam”: they are transmitted simultaneously.
  3. Tune the patch (frequency, substrate, dimensions, feed) and watch the impedance, S₁₁ and gain.
  4. Watch the wave propagate in the vertical cut; hover over it to probe E, H and the power density.

Reading the views

3D pattern
Radius and colour give the level in dB in every direction of the half-space above the array.
u-v space
The pattern seen from above: u = sinθ·cosφ, v = sinθ·sinφ. The centre is the array normal (θ = 0), the rim is the horizon (θ = 90°).
Excitation
Each patch drawn to scale. Hue encodes the feed phase, opacity the amplitude.
Vertical cut
Coherent sum of the waves emitted by every element. E(t) and H(t) are animated; in the far zone H = E / 377 Ω and is perpendicular to E.
Pattern cut
Level versus θ in the vertical plane containing the active beam.

Physical model

Patch
Width W = c / (2f) · √(2 / (εr + 1)), effective permittivity εeff, fringing extension ΔL (Hammerstad), length L = c / (2f·√εeff) − 2ΔL.
Impedance
Redge = 1 / (2·(G₁ + G₁₂)), then Rin = Redge·cos²(π·y₀ / L) for a feed inset at y₀. Around resonance: parallel RLC resonator whose Q is derived from the bandwidth.
Element
|E|² ∝ sinc²(k·W·v / 2) · cos²(k·Leff·u / 2) · (1 − v²).
Array
wmn = am·an · Σb Ab·exp(−j·k·(xm·ub + yn·vb)): each beam contributes its own phase gradient, and the weight sets add up.
Directivity
D = 4π·Pmax / ∬ P·sinθ dθ dφ, integrated numerically. Realized gain = D · (1 − |S₁₁|²).

Limitations to keep in mind