Review on Bingfu 4G LTE Antenna - 8dBi Magnetic Base SMA Male Antenna for Enhanced Wireless Connectivity with 4G LTE Wireless CPE Router, Cellular Gateway, Industrial IoT Router, and Mobile Cellular Devices by Ananta Crowley

The base is magnetic and is designed to be placed on a metal surface (the so-called ground plane). There is no need to use a ground layer as the antenna is designed to work with or without a ground layer. When you put it on the roof of your car it won't stay in place because the base is too small and the magnet is too weak. I don't know how to rate this product as I use it in a stationary position all the time. For me it's 5 stars because only the reliability of the antenna is important to me. But if you want to install this on your car, it probably won't work for you unless you fix it with epoxy. Then I would rate it 0 stars.