Microwave antennas

Antennas are of particular importance for microwave transmission. It is only as a result of the high antenna gain that it is possible at all to transport low transmit power of microwave equipment over large distances with an adequate signal level for the receiver. On the other hand, it is only possible through extremely intensive bundling of the electromagnetic radiation to use repeatedly one and the same frequency at a location and hence make efficient use of the precious frequency resources. In particular for telecommunication companies, many special constructions with in some cases huge dimensions have been developed in the course of the past decades.

Above all, there is a widespread use of parabolic dishes — in various sizes and with a range of properties. Dimensions between 30 cm (1 ft) and 4.6 m (15 ft), in small steps, are common. In certain conditions so-called shell-parabolic antennas are also being used nowadays. This type is marked by a particularly intense focussing and the highest possible cross polarisation decoupling. According to the concrete situation and requirements, the microwave link planner will choose the appropriate type. Andrew, Ericsson (Marconi/Bosch), Faini (Kathrein) und RFS are the most important suppliers for microwave antennas.

In the case of short-haul microwave links, the antenna and the microwave outdoor unit are often combined to form a single constructive unit. It is either the case that the antenna is integrated directly into the housing (e.g. in the case of Ericsson) or that the antenna and the outdoor unit are connected via an installation bracket or a coupling unit (e.g. in the case of Alcatel and NEC). In this way the equipment is particularly compact and can be installed at low cost. A separate installation is only unavoidable for larger antennas (at least 1.2 m / 4 ft diameter).