When you need to see inside the brain, you usually lie in a tight tube of an MRI scanner or get zapped with X-rays. Both methods are costly, bulky, and not always available. Engineers explored an alternative — a radar that sends weak radio pulses and catches reflections from different tissue layers.

In a computer model, they filled a head with materials mimicking the density of brain, bone, and fluid. They aimed two types of antennas at it — a small rectangular 'patch' and a smoothly flaring plate (Vivaldi). The former works like a narrow flashlight: the signal focuses into a spot and clearly indicates where a lump hides. The latter resembles a wide floodlight: it covers a large area but loses sharpness.

The result is encouraging: the 'patch' confidently highlights a tumor the size of a cherry pit, while the 'fan' suits a quick scan of a hemisphere. This is only a simulation, but it shows that radio waves could become a light, harmless tool — especially in rural areas and mobile clinics where you can't haul a multi-ton magnet.