A Study on High Gain Circular Waveguide Array Antenna Using Metamaterial Structure

A new method of improving the gain of circular waveguide array antenna using metamaterial structure is presented in this paper. The electromagnetic characteristics of metamaterial and high-gain circular waveguide antenna with the metamaterial structure are studied by using the numerical simulation method, which were also compared with those of the conventional circular waveguide antenna. The simulation results show that this method is effective and the metamaterial structure can realize congregating the radiation energy, so the gain of the antenna is increased and the side lobe level is decreased. Keywords-Metamaterial structure; Circular waveguide antenna arrays; High-gain In this paper, we present a new high gain circular waveguide array antenna design using metamaterials structure. The properties of metamaterial structure and the radiation characteristics of the array antennas are investigated by numerical method. Our studies demonstrate that the metamaterial structure can realize an effective refraction index which can be close to zero and congregate the radiation energy, and the array antenna with metamaterial structure can obtain a great improvement of the antenna gain, in comparison with the conventional array antenna. II. PRINCIPAL CHARACTERISTICS OF METAMATERIAL STRUCTURE The metamaterial,which is studied in this paper, is composed of copper grids with a square lattice and whose period is equal to a mm (in the x-axis and y-axis directions). The grids' spacing in the z-axis direction is H mm, and the edge of the square holes of the copper grids is (a-r)mm. the structure of the metamaterial is shown in figure 1.