GoKawiilNot so many decades ago, in much simpler and slower times, many Wi-Fi routers shipped with just a single antenna that could only handle one wireless data stream at a time. As Wi-Fi got better, the internet got faster and devices rapidly multiplied across households. The number of antennas on routers did, too. Today, there are routers with as many as eight antennas.
At first glance, routers with many antennas might come off as a simple marketing gimmick, but there's a good reason why single-antenna routers stopped being enough. Yes, even that alien spider-looking router with eight antennas has a good reason for existing, but that doesn't mean it's for everybody. Picture an antenna as a single-lane road. In a small town, that single lane is plenty. Take that same road into a busy city, and traffic congestion builds up fast. In the early days, when one of the internet's main uses was email, a single antenna was plenty too, but that's no longer the case. So instead of building routers with just one lane, manufacturers started building ones that could run several lanes of traffic at once, using a trick called MIMO (multiple-input, multiple-output). This tech is what actually makes multiple antennas useful, because contrary to what most people think, simply bolting on extra antennas without MIMO causes more problems than it solves.