Show
Signal strength along the path
With the wall
Without the wall
Radio waves don't just travel in straight lines: they bounce, bend, spread around corners, scatter and fade. This is a live wave simulation: pick a behaviour and watch the waves do it.
A snapshot of the wave: red is where the field is positive, blue where it's negative. The distance from one red crest to the next is one wavelength. The picture is a flat slice, so a small source spreads out in circles.
The average power at each point over the last few cycles, in dB relative to the strongest spot. It shows what a device would measure: shadows behind obstacles, bright and dark bands where waves overlap, and how much gets through a wall.
The picture is 20 wavelengths across: about 2.5 m at 2.4 GHz, 1.1 m at 5 GHz and 0.9 m at 6 GHz. Objects are drawn at their real size in centimetres, so switching band changes how big they are compared with the wave. That's why the same gap or object behaves differently at 2.4 and 6 GHz.
It solves the wave equation on a grid (the finite-difference time-domain method used by real RF design software), in two dimensions. Metal is a perfect conductor, glass, wood and concrete slow the wave down, and lossy materials absorb some of it. The edges of the picture soak up waves so they don't bounce back.
A flat, 2D world with one polarisation. Material values are typical, and real walls vary widely with moisture, rebar and construction. The attenuation figures are a guide, not a site survey.
See all these effects combined in a room in the Multipath Simulator, clearance for diffraction in the Fresnel Zone Calculator, and wall losses in a link budget in the Power Budget Calculator.