Efficient methods for determining installed performance of antennas on large vehicles

Modern vehicles (Automobiles, Ships, Satellites and Aircraft) all have a limited amount of physical space to mount an ever-increasing number of different communications and navigation systems. This is exasperated by both the use of materials, like cardon fibre, and the fact that large areas of the vehicles structure cannot be used to mount antenna, due to aerodynamic or other requirements. A RF system engineer is required to be able to quickly and accurately find the optimum locations to mount a number of antenna systems, whilst considering a number of different and sometimes contradictory antenna performance parameters. Therefore, defining the optimum antenna locations, for numerous antenna systems, is a Multi-Objective Problem (MOP) and lends itself to the use of Multi-Objective Evolutionary Algorithms (MOEA). A number of papers have been published for antenna placement using a global optimisation tool to define the optimum location by minimising the mutual coupling between the antennas; however, these papers only consider a single objective. This thesis will demonstrate that the MOEA methodology can be used to accurately, quickly, and robustly define the optimal antenna locations, using multiple objectives of inter antenna mutual coupling and RF radiation pattern.

As an MOEA compares many objective solutions (fitness functions), then the algorithms behind these fitness functions must be simple, quick, and accurate. Consequently, this thesis covers the following aspects:

• Defining how the communication system parameters are affected by installing a monopole antenna on different ground planes.

• Defining a fitness function for predicting the RF interoperability/mutual coupling between antenna systems, objective number 1.

• Defining the fitness function for predicting antenna RF radiation pattern installed performance, objective number 2.

Finally, it will be shown that a multi-objective optimisation tool, using MATLAB® on a modest desktop computer, can be used to accurately and quickly calculate the optimum antenna locations on a vehicle structure.