Research On Applications Of Metamaterial In Antenna Design

Metamaterials, which have strong capability of manipulating electromagnetic waves, are commonly composed of subwavelength unit cells with a specific geometry arranged in a regular or irregular layout. The material characteristics of metamaterial depends on the structure and spatial arrangement of basic unit. Metamaterial antennas designed by traditional antennas combined with metamaterials not only enrich the types of antennas, but also provide a new way for the breakthrough of the bottleneck in traditional antenna design, further promoting the development of wireless communication systems. In this paper, the application of metamaterials in antenna design is studied,which is mainly aimed at two important branches including metasurfaces and spoof surface plasmon polaritons (SSPPs). The main contexts and contributions are shown as follows:1. A circularly polarized metasurfaced antenna which is a half-wavelength dipole right above the metasurface with polarization conversion function is designed. Taking advantage of cross-polarization between the reflected wave and the direct wave emitted from the dipole antenna, circularly polarized wave can be possibly generated. In addition to the simple structure, the proposed metasurfaced antenna can achieve good circular polarization performance with wide axial-ratio beamwidth of 123°and 90° in ?=00 and ?= 90° planes respectively and realize effective radar cross section reductions in the main direction of polarization.2. A tunable spoof surface plasmons antenna based on a bulleye structure is proposed, which utilizes sinusoidally modulated reactance disturbance to convert SSPPs constrained in metal surface to the radiated wave in free space and introduces an marginal circle to reduce back lobe. The main radiating lobe of this antenna exactly agrees with the angle of the theoretical design and can tuned to scan in a certain frequency band.3. A plasmonic antenna based on a tapered slotline antenna which makes use of the periodic grooves etched on the ground in both side of the slot to excite SSPPs is designed. Sinusoidally modulated reactance disturbance is introduced to realize the conversion from the SSPPs to the radiated wave in free space. Moreover, the elevation angle of the major radiating lobe is set to the complementary angle of inclination of slotline to ensure end fire radiation.