Performance Enhancement Of Integrated Antennas Using Metamaterials And Characteristic Mode Theory

Download or read book Performance Enhancement of Integrated Antennas Using Metamaterials and Characteristic Mode Theory written by Ozuem Anthony Chukwuka and published by . This book was released on 2020 with total page 0 pages. Available in PDF, EPUB and Kindle. Book excerpt: The demand for miniaturized mobile wireless systems have increased the need to integrate electrically small antennas which are generally characterized by poor performances and low efficiency. Methods such as the use of dielectric, slots, parasitic components, ... have been applied over the years to enhance the performance of such antennas. However they are empirical and based on time-consuming optimisations. Other methods like antenna current optimization based on modal analysis are systematic methods which have been proposed. It has also been shown that the use of artificial materials known as metamaterial inclusions as parasitic element help to improve antenna performance at lower cost. The choice of the right inclusion for an antenna design is complicated especially when the antenna is non-canonical and arbitrary.In this thesis, we propose a systematic method for enhancing the performance of antenna using metamaterial inclusion as a parasitic element. The method is used for designing parasitic metamaterial antenna with the potential to analyse both the radiation and scattering properties of the parasitic metamaterial design. It uses the characteristic modal method to evaluate the quantitative stored energy of metamaterial inclusions which provide quantitative information on the near-field behaviour of the inclusion. The modal stored energy method is compared to the effective parameter method for describing inclusions and they both show good qualitative agreement. In the parasitic metamaterial antenna design process, characteristic mode is applied to get an insight into the radiation properties of the structure and an inclusion is chosen to compensate the stored energy of the antenna element based on the quantity of its modal stored energy. The coupling between the antenna and the inclusion is analysed using the inter-modal coupling co-efficient. It represents the scattering between the antenna and the inclusion and defines how the positioning and separation distance between the two elements affect the overall performance of the metamaterial-inspired system. The proposed methodology is validated with a prototype that show a good agreement between the simulated and measured result. The method is further applied in investigating the enhancement of integrated antenna using electromagnetic cloaking. The cloak couples to the passive element in its vicinity and allow the active antenna element to operate with a better radiation efficiency. The proposed method show usefulness for future design of parasitic metamaterial systems with enhanced performance.