Study On The Metamaterial Applications In The Microstrip Antenna Miniturization Design

Left-handed materials(LHMs) are characterized by a negative effective permittivity and simultaneously a negative effective permeability. It is different from the traditional right-hand material, whose electric field, magnetic field and wave vector satisfy the left-hand rule, that means the phase velocity and group velocity are in the opposite directions, so they have many unusual properties, such as negative refraction of light, reversed doppler effect, reversed Cherenkov radiation, the perfect lens effects and etc. Metamaterials was first proposed in2002. The development of the left-handed material has been regarded as one of top ten scientific and technological breakthroughs in science community in2003, and metamaterials have been the cutting-edge in the field of electromagnetic research.Composite right/left-handed (CRLH) transmission line is a new type of transmission line structure based on the theory of metamaterials, it shows the characteristics of the left-handed material in the low frequency band and right-handed material in the high frequency band. Moreover, compared to the traditional left-handed material structure, composite right/left-handed (CRLH) transmission line has certain advantages in insertion loss, bandwidth, etc. Thus the research of composite right/left-handed (CRLH) transmission line has been one of the focus of the left-handed materials in the field of microwave antenna. Studies have shown that the composite right/left-handed (CRLH) transmission line having a very distinct advantage in the miniaturization of microwave devices.Firstly, the basic concept of metamaterials, as well as the research progress of left-handed material at home and abroad was introduced in this paper, then given a brief introduction on the concepts and principles of the microstrip antenna and the electromagnetic parameters extraction of the metamaterials. Afterwards, based on the optical transformation theory, the constitutive parameters of the two-dimensional arbitrarily shape cloak and electromagnetic rotator can be obtained by numerically solving the Laplace’s Equation with the given boundary condition. The effection of this method was demonstrated by the numerical simulation with a full-wave simulations software. Next, a small antenna based on circuit model of composite right/left-handed (CRLH) transmission line was designed, its zero-order resonance mode of the antenna was obtained by adjusting the structure of composite right/left-handed (CRLH) transmission line. And then, the operating frequency of the antenna no longer depends on the geometry of the antenna, but only the inductance and capacitance of the left-handed transmission line, the antenna size was greatly reduced. Two small microstrip antennas operating at ISM band(2.4GHz) were studied by zero-order resonance theory, which meeting the requirement of wireless local area network(WLAN:2.4 GHz-2.4835GHz). Compare to conventional antenna, the proposed two antennas in this paper have smaller size.