In areas on the very edge of network coverage, using external outdoor directional antennas to connect to LTE-WiFi routers is sometimes the only solution for higher download speeds. In more challenging cases, the external antennas should offer high gain performance in order to connect to the network effectively.
The external antenna is mounted on a wall or a roof of building either directly or via a pole and is directed towards the mobile operator’s base station. Due to the antenna’s high gain, a strong and stable 4G signal is acquired and fed to the LTE-WiFi router via a low loss coaxial cable.
There are typically two types of external directional antenna that can be deployed in access applications. The first type is a multi-element antenna known as a yagi or log periodic antenna. In simple terms this looks like a regular TV aerial and is quite long in overall length. The second type is what is known as a panel antenna, usually square or rectangular in shape. The panel antenna typically is lower profile or more discreet, but doesn’t offer as much gain as yagi style antenna.
A LTE-WiFi router usually provides two antenna ports for LTE antennas. This enables the router to take advantage of MIMO (multiple in/multiple out) communications which mean two antenna elements are used to increase download speeds. In antenna terms, this means using either two antennas or a MIMO antenna which has two antenna elements that work concurrently. Therefore for access applications, it is advisable to use a MIMO antenna or 2 individual antennas to maximise system performance.
An example of the multi-element directional antenna, is the LTE-MIMO-YAGI. This is based on two separate elements offset from each other by 45 degrees (known as X-polarisation). With a peak gain of in excess of 11 dBi on both elements, this antenna system is fed by two 10M low loss cables and offers best-in-class performance for challenging LTE access sites. An optional J-pole is available if a suitable mounting fixture on the building is not available.
The SMP-4G-MIMO is an example of a discreet directional panel antenna. The effective gain is lower than the LTE-MIMO-YAGI, however the aesthetics of the antenna mean that is preferred in some situations where a large multi-element antenna is undesirable. The SMP-4G-MIMO can be bundled with very low loss cables such as BWL195 or RF400 to customised lengths to offer a solution tailored for the installation.
Notwithstanding spurious claims made by some suppliers about antenna gain, typically directional antennas for access or enterprise site applications do not exceed gain figures of about 11 dBi. Some suppliers will claim to have antennas with 35 dBi gain or similar and these suppliers should be discounted immediately as these gain figures are just not true. Connex Technologies Ltd only supplies antennas and RF accessories from best-in-class manufacturers and the specifications stated are a true reflection of antenna performance.