Cellular antennas play an essential role in the operation of cellular routers. They help improve the signal quality and strength received by or sent from a cellular device. While some cellular devices work without an antenna, most require an internal or external antenna. Internal antennas are mounted inside the case of the cellular router and are not usually accessible. External antennas are either attached directly to the device or connected via a cable. Antennas can be single or multiple functions. For instance, an LTE antenna will boost only one frequency, LTE, while a 3-in-1 antenna may boost LTE, WiFi, and GPS. It is possible to get up to a 9-in-1 antenna.