There has been a large and steady increase in the number of microwave point to point links, and this trend looks set to continue as the technology becomes cheaper and finds applications in new areas. Whilst microwave links are often seen as a 'temporary' solution in many situations, i.e. as a means of establishing communications relatively quickly before cabling can be installed, in many cases the cost of cabling can be prohibitive and the microwave link becomes the only variable option. With the increasing demand for radio communications services it is becoming more important to utilise the allocated frequency bands efficiently. The directional properties of both the transmit and the receive antenna contribute equally to the determination of the re-use of available frequencies in a line of sight region. For point to point applications the ideal antenna would have a small aperture, high gain, very low sidelobes and a beamwidth wide enough to facilitate and maintain alignment in adverse conditions. Unfortunately, these are conflicting factors. Maximising the antenna gain differential between the wanted and unwanted directions will directly reduce co-channel interference, and this can be achieved in a number of ways. The paper aims to identify the ways in which antenna performance can be improved and to quantify the benefits in terms of the impact on link density. The results of various methods of analysis are presented.
展开▼
