Research On Metamaterials In UHF RFID Antennas Application

Metameterial and UHF(Ultrahigh Frequency) RFID(Radio Frequency and Identification) are both hotpots currently. Based on the research of these two points, this paper gives the application of the RFID antenna which utilizes the technology of metamaterial. The main contents are as follows:Firstly, there gives a UHF RFID microstrip patch antenna array which is applied to the real industry environment. And a UHF RFID Quasi-Yagi antenna is also presented. Both of them are manufactured, tested and analyzed with electromagnetic quality. And the parameters of S11, gain and pattern are given.And then, an extraction method about constitutive parameters of the metamaterial unit,and also the program coding, which leads to further design on a kind of electric metamaterial and a kind of magnetic metamaterial, are both presented. The influence of the resonant frequency produced by the structural parameters is given. Finally the constitutive parameters are also shown in this paper.Further more, the well designed metamaterial unit is combined with the UHF RFID microstrip patch antenna array and the UHF RFID Quasi-Yagi antenna respectively. Based on the two simulation datas, the results come out in the following. For the microstrip patch antenna array, the gain improves 2d B and the 3d B beamwidth reduces by 5.2 degrees. For the Quasi-Yagi antenna, the gain improves 2.5d B and the 3d B beamwidth reduces by 180.5 degrees.Finally, a system test is presented by researching the changes of the electromagnetic characteristics of the UHF RFID antennas, which is produced by the addition of the metamaterial. The test method is given in detail and the result data verifies the correction of the simulation.