Electromagnetic Metamaterials In The Application Of The Electromagnetic Radiation

Metamaterials are broadly defined as artificial effectively homogeneous electromagnetic structures with unusual properties not readily available in nature. Due to their unique properties that may lead to unconventional phenomena in transmission, radiation, and scattering of electromagnetic wave, metamaterials, with potential applications in many domains, have recently received much attention from various research groups. In2003, the discovery of left-handed materials (one of the metamaterials) was regarded as one of the most ten significant progresses in science community, and the experimental study of two-dimensional cylindrical cloak based on left-handed materials won the same honor in2006. Metamaterials have opened up new areas of research and will have a significant impact on communications, radar, defense, microelectronics, medical imaging, et al.Based on the theoretical EM analysis of metamaterials and ideas of the related novel antennas, this paper firstly investigates the wave propagation characteristics in metamaterials, and then focuses on its applications in antenna technology. The original works of this paper are as follows:1. A modified frequency-dependent finite-difference time-domain (FDTD) method is presented to study the electromagnetic resonance of metamaterials. Both the negative permittivity and permeability are realized with the Drude medium model. Then, the characteristics of one-dimensional wave propagation and two-dimensional electromagnetic energy localizing in metamaterials are analyzed by using this numerical method.2. Investigation and analysis of the electromagnetic resonance of a periodic array of split rings resonators (SRRs) and wires in free space are provided. We numerically verify a series of unusual properties of SRR/Rod structure by software. Then, two aspects of work are carried out. Firstly, the bandwidth of negative permeability of Smith structure is expanded by introducing super-cells. Secondly, a dual-band metamaterial is proposed by using double SRRs resonator coupling structures. 3. A novel dual-beam scanning leaky-wave antenna is proposed and investigated based on composite left/right-handed transmission line (CRLH-TL). The spatial scanning range (-600,+600) can be achieved when frequency varies.4. The applications of left-handed materials in antennas are studied, to improve the performances of antennas and (or) reduce the antenna size, we design a series of compact and wideband zeroth-order resonator (ZOR) antennas and a multi-mode antenna based on the unusual resonance characteristics of left-handed materials.