Microstrip Antenna Design Based On Left-Handed Materials And Photonic Bandgap Structures

The conventional microstrip patch antenna has low gain and low directivity. How to improve the gain and directivity of microstrip patch antenna is become one of the research hot spot. Metamaterial is a new type of artificial electromagnetic material, and has electromagnetic properties that are not found in nature. So metamaterials can lead to a broader view and wide applications in antenna technologies. Left-handed materials and photonic band gap structures will provide a new direction for the design of the microstrip antenna. This thesis mainly studied on the application of the microstrip antenna with lefthanded materials and photonic band gap structures. The main works are as follows:1. The basic theories and design methods of left-handed materials are studied. Then the Smith's left-handed materials and new left-handed materials are designed. Electromagnetic characters of the periodic structures are obtained by scattering parameter extraction methods. The influences of geometric parameters on the left-handed material properties are discussed. The desired left-handed frequency bands are obtained with different shapes, sizes and arrangements of the left-handed materials.2. The advantages and disadvantages of the numerical analysis methods on photonic band gap structures are contrasted. The design methods of photonic band gap structures are studied. Bragg scattering theory are used to design photonic band gap structures, and computer simulation software are used to optimize the size of photonic band gap structures, the satisfactory photonic frequency band gaps are obtained. The applications of microwave photonic band gap structures in microstrip antenna are described in detail.3. According to the basic theory of microstrip antenna, rectangular microstrip patch antenna is designed. Then the radiation characteristic and the impedance matching of the rectangular microstrip patch antenna are analyzed. New type microstrip patch antenna with left-handed materials and photonic band gap structures are designed. The influences of lefthanded materials and photonic band gap structures on the performance of the antenna are analyzed. The simulation results demonstrate that left-handed materials and photonic band gap structures can reduce the return loss of the antenna and improve the antenna's gain and directivity.4. By using the cavity model method to analyze the radiation field of cylindrical microstrip antenna, cylindrical microstrip patch antenna is designed. New type cylindrical microstrip patch antenna with left-handed materials and photonic band gap structures are designed, and its performances are compared with the traditional cylindrical microstrip antenna. The left-handed materials and photonic band gap structures are applied to cylindrical microstrip antenna at the same time, satisfactory results are obtained. The simulation results proved that the left-handed materials and photonic band gap structures can improve the performance of the antenna obviously.