Design and development of a hybrid near field and far field antenna measurement system, The

Abstract

In this thesis, a dual-purpose antenna chamber measurement system is presented. The measurement system is an anechoic chamber where the near-fields or far-fields of an antenna can be measured with the same equipment. A custom software was developed to perform either type of measurement. This antenna chamber is a much more cost-effective solution compared to conventional antenna chambers, where separate chambers are used for different types of measurements. This thesis presents the developed software and hardware for a custom-made chamber design that produces accurate results.

Both mechanical and software capabilities are introduced, but emphasis is put on the development of the software capabilities throughout this thesis. Both theoretical, numerical, and experimental analysis is introduced to verify the performance of the chamber. The necessary methods to perform the near-field to far-field transformations are presented and discussed in detail. A circular patch antenna is designed, simulated and tested to verify the accuracy of the far fields measured in the chamber, and a broadband horn antenna is measured to verify the accuracy of the near field measurements. The measured results for these two types of antennas matched the expected results, verifying the accuracy of each measurement type. Lastly, an antenna array is tested using both far field and near field systems, and the results from both measurement system were compared with each other. Good agreement is obtained, but due to the physical limitations related to the equipment used in the chamber and the size of the antenna some differences in the far field patterns are observed.