Network Characteristic Modes Optimisation for Wideband and Superdirective Small Antennas
Abstract
The recent development in communication systems requires more compact antennas to be integrated on a limited space in order to operate on the desired radio standards. Nevertheless, as the antenna size decreases with respect to the wavelength, it becomes limited by bandwidth, efficiency and directivity. Recently, several researches have focused on a new class of compact antennas with high directivity. Such antennas are called superdirective anetnnas. However, despite the high directivity achieved, the antennas suffer from very narrow bandwidth and low efficiency. This paper presents an approach to enhance the bandwidth of superdirective arrays based on characteristic modes analysis. By optimizing the modes in the unit element of the array, it is possible to obtain a wideband superdirective array. © 2018 International Union of Radio Science URSI.