MUTUAL COUPLING OF THE ANTENNAS ON THE HELICOPTER TAIL

Abstract

For systems to interact, the frequencies have to be above a specified power threshold, and their spatial as well as their time domain characteristics have to be overlapping. When any EM wave transfers from one system to another the systems are said to be ‘coupled’. This term is used for systems when this occurs unintentionally. At the design stage when positions of antennas are continually being changed, a quick and easy means of estimating the coupling between antennas is required. Computer modeling cannot be used at this stage, since the change of position of one antenna is invariably accompanied by the change of positions of a number of adjacent antennas, and a quick method of determining the impact is required. Additionally it is more satisfactory to perform calculations since the coupling has to be estimated over large combinations of antennas at the design stage, and a spreadsheet is more amenable to the frequent changes that occur during the design stages of a new aircraft or complete systems modification of an existing aircraft.