Overview
When you see "5G" appended to a Wi-Fi network name, it refers to the 5GHz frequency band (Hz is the unit of frequency), not the fifth-generation mobile network commonly called 5G. Consumer routers are commonly single-band or dual-band. A single-band router operates on 2.4GHz, while a dual-band router offers both 2.4GHz and 5GHz. If you see two identical SSIDs and one includes "5G", that typically indicates a dual-band router exposing both bands.
Differences Between 2.4GHz and 5GHz
2.4GHz has a longer wavelength, experiences less attenuation over distance, and penetrates obstacles more effectively, so it is better for longer range and coverage through walls. However, its maximum data rate is generally lower than 5GHz, and the 2.4GHz band is often more congested because many devices use it.
5GHz has a shorter wavelength and higher attenuation, so it provides shorter range and weaker obstacle penetration compared with 2.4GHz. In exchange, 5GHz supports higher data rates and typically encounters less interference from other devices.
Which Band to Choose
If there are obstacles between your device and the router or the distance is relatively long, 2.4GHz is usually the better choice. If the device is close to the router with few obstructions, 5GHz will typically provide higher throughput.
Antenna Count and Signal Strength
Having more antennas on a router is primarily about increasing throughput rather than extending coverage or increasing transmit power. A router's signal strength is determined by its transmit power, which is subject to regulatory limits. In many markets, regulatory limits cap the maximum transmit power for consumer routers (for example, 100 mW in some jurisdictions). Regardless of antenna count, the maximum allowable signal power is constrained by those limits.
MIMO and Multiple Antennas
The practical benefit of multiple antennas is to enable MIMO (multiple input, multiple output) techniques. MIMO requires multiple antennas so the router can split data streams across antennas and send them simultaneously, with the receiver recombining the streams. A simple analogy: a single antenna is like a single traffic lane; MIMO creates multiple lanes to increase throughput under higher traffic load.
