# Thread: Minimum wavelength required for a radio wave to penetrate the skull?

1. What is the smallest wavelength required for a radio wave to pass through the skull and reach the brain in a human being?

How can the wavelength be calculated?

What type of antenna would be required to produce this radio wave?

2.

3. Originally Posted by Sci-fi guy
What is the smallest wavelength required for a radio wave to pass through the skull and reach the brain in a human being?

How can the wavelength be calculated?

What type of antenna would be required to produce this radio wave?
Your question presupposes something that isn't true. There's no minimum wavelength requirement. Indeed, there is a minimum wavelength constraint.

You are, basically, meat, as a first approximation. The skin depth of meat is about 10cm for 2.45GHz (the frequency used by ordinary microwave ovens). The skin depth varies inversely as the square-root of frequency.

The product of wavelength and frequency equals the speed of light, so you can compute one given the other two. A 3GHz wave in free space has a wavelength of 0.1m.

As for your last question, antennas do not produce radio waves; they radiate them. To do so efficiently requires that they be at least a reasonable fraction of a wavelength.

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