Heterologous To The Media In The Antenna Technical

As a new type of electromagnetic material, left-handed materials(LHMs) have very special electrodynamic properties, such as the reversal of Snell's law, the Doppler effect, and Cerenkov radiaton. Basing on the research of LHMs, this thesis focuses on the study and applications of LHMs to antennas.The first part is the design of double negative frequency selective surfaces. The theory of general frequency selective surfaces and some typical frequency selective surfaces are introduced. Then, making use of the dispersion property of LHMs, a simple double negative frequency selective surface is designed. How the parameters of the frequency selective surface affect the bandwidth is investigated.The second part is the design of an open cavity antenna using the above frequency selective surface. The pattern of the antenna is studied in numerical simulations. The influence of the parameters of the antenna to the band and the pattern is also investigated.The third part is about the research on the improvement of the directivity of antennas using wire medium. The conditions of the highly directivity is shown, and numerical simulations are carried out, and then, the radiation pattern and directivity is observed in the certain bandwidth. Finally, we construct 3D highly directive antenna based on the hyperbolic medium.