Based On The Multi-band And Wideband Characteristics Of The Fdtd Method For The Microstrip Antenna

With the rapid development of mobile communication technology, microstrip antennas have been used broadly for their small volumes, low profiles, good integration and low costs. Despite many advantages of microstrip patch antennas, they have some considerable drawbacks, for example narrow bandwidth and low gains, which prevent the application of microstrip patch antennas.Recently, an artificial composite material named "metamaterial" has begun to attract more and more attention of researchers in solid physics, material science, optics and application electomagnetics, due to it's specific electromagnetics, such as negative permittivity negative permeability and negative index of refraction. Applying the metamaterial to microwave to get some novel microwave devices will become a brand-new subject.Combining the theory of microstrip patch antenna design with the "metamaterial", a novel wideband antenna is presented. This antenna is composed of Right/Left-Handed transmission lines. The impedance bandwidth can reach around 108.3%, which has rarely been reported for single layer and single patch antennas. As the input-return is -10dB, the bandwidth is around 2.6GHz, including the frequency 0.9GHz, 1.8GHz, 1.9GHz, 2GHz and 2.4GHz, which are used in wireless communication systems. The operating frequency of the antenna is 2.4GHz and the physical size is 40 × 1 0 mm~2 which is smaller than conventional rectangle patch antenna. Otherwise, a double frequency antenna is present combining the technology of improving bandwidth. The operation frequencies of the double band antenna are 2.4GHz and 5.57GHz. The impedance bandwidth can reach around 16.7% at 2.4GHz and 5.38% at 5.57GHz, which can be used in wireless communication systems. In This paper, FDTD numerical computation method is used to analyse and design antennas. By setting perfectly matched layer (PML) absorbed boundary condition and partitioning inhomogeneous adaptive mesh, the accuracy of FDTD numerical computation is enhanced. Comparing the simulation result by FDTD method with the simulation result by CST, confirms that FDTD algorithm is more useful when calculate this kind of structure models. In order to get the structure of antenna with good performance, different structures must be simulated. The designed antenna with good capability was produced with PCB technology. In this way, the three antennas with good performance, which can be used in wireless communication system is designed at last.