Why do routers have so many antennas?

Not long ago, in a much simpler and slower era, many Wi-Fi routers came with a single antenna that could only handle one wireless data stream at a time. As Wi-Fi improved, the Internet became faster and devices quickly proliferated in homes. Also the number of antennas on routers. Today there are routers with eight antennas.

At first glance, routers with many antennas may seem like just a marketing gimmick, but there’s a good reason why single-antenna routers aren’t enough anymore. Yes, even this spider-looking alien router with eight antennas has a good reason to exist, but that doesn’t mean it’s for everyone. Think of an antenna as a single-lane road. In a small town, this single lane is enough. Take that same road into a busy city and traffic jams build up quickly. In the early days, when one of the main uses of the Internet was email, a single antenna was also enough, but this is no longer the case. So instead of building routers with just one lane, manufacturers began building ones that could handle multiple lanes of traffic at once, using a trick called MIMO (multiple-input, multiple-output). It’s this technology that makes multiple antennas useful, because contrary to what most people think, simply installing additional antennas without MIMO causes more problems than it solves.

Using MIMO, routers with multiple antennas can carry more data using a sophisticated technique called spatial multiplexing. So, more antennas accommodate more data lanes, but that doesn’t mean that more antennas automatically equal more data lanes. The router also needs the appropriate internal hardware to turn these lanes into separate data paths.

Another use of multiple antennas is beamforming. In simple terms, this means that multiple antennas allow your router to determine where your device is and then focus its signal on it. And the more antennas there are, the more your router can do this, because each additional antenna gives it another signal that it can fine-tune. Think of several people throwing stones into a pond at carefully timed times. Their ripples can turn into a stronger wave in one chosen location and remain weaker elsewhere. Beamforming requires multiple antennas for the same reason: the router coordinates their signals so that they combine more strongly around your device. A single antenna has no other signals to coordinate with.

Signal diversity and reliability are other important reasons for multiple antennas. In a home, Wi-Fi signals do not reach the recipient directly; instead, they bounce off walls, furniture, metal objects, and even people. So having multiple antennas spaced apart ensures that at least one of them gets a clean signal even if others don’t. Additionally, multiple antennas are required for MU-MIMO (Multi-User Multiple-Input Multiple-Output). Older routers served one device at a time before quickly moving on to the next. MU-MIMO divides a router’s antenna array so that it can communicate with multiple devices simultaneously.

For most people and homes, a router with eight antennas is excessive; a good router with two to four antennas is generally more than sufficient. In fact, the most important thing is not just the antennas; Wi-Fi standards and software also play an important role in a router’s performance. If coverage is one of your concerns, a router with eight antennas might be a reasonable choice, as you would have more antennas to adjust to improve coverage. But for coverage cases, setting up a mesh network is generally a more reliable solution than simply having more antennas.

For businesses, a high-capacity router with more antennas and data streams can be useful, especially in offices, coffee shops, or other places where many people are connected at the same time. But once again, beyond the number of antennas, the Wi-Fi standard and software play a major role in the proper functioning of the network, even when multiple devices are connected. Another thing to know is that a newer, faster Wi-Fi router with more antennas does not necessarily mean faster internet speed. Ultimately, your maximum internet speed is capped by your plan, and a new eight-legged, spider-like router won’t magically get around that.