Millimeter wave (mmWave) refers to electromagnetic frequencies between 30 GHz and 300 GHz, where wavelengths range from 1 to 10 millimeters. This spectrum enables extremely fast data transmission.
Millimeter wave technology is a key component of 5G networks and is also used in airport body scanners and automotive radar systems.
Millimeter wave describes a specific band of the electromagnetic spectrum where wavelengths are measured in millimeters—typically 1 to 10 mm, corresponding to frequencies of 30-300 GHz. The name is straightforward: waves in this range are literally a few millimeters long.
What makes millimeter wave technology significant is bandwidth. These high frequencies can carry enormous amounts of data, enabling the ultra-fast speeds promised by 5G networks. Download speeds can theoretically reach multiple gigabits per second.
However, there’s a tradeoff. Millimeter waves don’t travel far—a few hundred meters at most—and they’re easily blocked by buildings, trees, rain, and even your hand. This means mmWave 5G requires many small cell sites placed close together, unlike traditional cell towers that cover miles.
For EMF exposure considerations, millimeter waves represent a relatively new addition to our wireless environment. While higher in frequency than 4G signals, mmWave radiation is still non-ionizing and doesn’t penetrate deeply into biological tissue. The energy is largely absorbed by the skin’s surface layers.
The health research specifically on millimeter wave frequencies is less extensive than for lower RF frequencies, simply because widespread consumer exposure is new. Some researchers have called for more studies on long-term effects, particularly regarding skin and eyes, which absorb most mmWave energy.
Airport body scanners also use millimeter wave technology—these systems scan passengers without ionizing radiation, creating images based on how mmWave energy reflects off the body.
