Meaning
Electromagnetic spectrum band with wavelengths between one and ten millimeters, corresponding to frequencies from thirty to three hundred gigahertz. In high-data-rate wireless systems, millimeter wave technology is used to provide ultra-wide bandwidths for short-range communication. This spectrum band is bounded by the lower microwave frequencies and the higher sub-terahertz region.
Material Loss
Dielectric loss increases dramatically as the operating frequency of the circuit rises. At millimeter wave frequencies, standard circuit board substrates like FR4 are too lossy, requiring the use of specialized materials such as polytetrafluoroethylene or liquid crystal polymer. These high-performance materials prevent the signal from dissipating as heat before it reaches the antenna elements.
Device Integration
Miniaturization is both an advantage and a challenge for the thermal and mechanical design of the device. The short wavelengths of millimeter wave signals allow antennas to be integrated directly into the semiconductor package or onto the main board. However, this high density means that heat from the power amplifiers is concentrated in a tiny area, requiring thick copper ground planes and thermal vias.
Propagation Path
Line-of-sight propagation is generally required because high-frequency signals do not penetrate solid objects easily. Human hands, office walls, and outdoor vegetation can block the signal completely, disrupting the connection. To maintain the link, devices use steerable antenna arrays that bounce the millimeter wave signals off nearby reflective surfaces to find an alternative path to the base station.
This capability is managed by fast switching algorithms in the transceiver that scan the environment in real time to select the best beam configuration for the current physical layout.
