Steering Beams

Phased arrays, radar and 5G

An interactive lesson with 6 steps, about 5 minutes: you predict, drag and solve, with instant feedback on every answer. It runs in your browser and needs JavaScript.

What you’ll learn

• Antennas in a row interfere: their waves add up in some directions and cancel in others.
• A phase step $\varphi$ between neighbours steers the beam to $\pi\sin\theta = -\varphi$ (half-wave spacing).
• Phased arrays power modern radar, 5G and satellite internet; wide spacing makes grating lobes.

Steps

1. Two antennas
2. Delay to steer
3. Point the beam
4. How narrow?
5. Radar without dishes
6. Grating lobes