Radio frequency sensors are devices that detect and measure electromagnetic waves in the radio frequency spectrum. They are commonly used in various applications, including telecommunications, security systems, and environmental monitoring. These sensors can pick up signals from devices like cell phones, Wi-Fi routers, and radar systems, allowing for the analysis of data transmitted over the air. These sensors work by converting radio waves into electrical signals, which can then be processed to extract useful information. They are essential in industries such as automotive for keyless entry systems and in smart homes for controlling devices remotely.