| Metamaterial is an artificial electromagnetic hybrid material with extraordinary properties in a certain range. Microstrip leaky-wave antenna has a major feature that its characteristic of main beam scaning is depended on working frequency. By applying the structure of composite right/left handed transmission line(CRLH-TL) to the design of metamaterial microstrip leaky-wave antenna, the performance of beam scanning of the novel antenna can be enhanced in some degree.In recent years, applying metamaterial to the design of the microstrip leaky-wave antenna to enhance its performance is becoming a high value topic which have received widespread concern in the scientific and engineering communities. This thesis is mainly aimed at studying the performance of using metamaterial to design microstrip leaky-wave antenna to enhance its beam scanning characteristic. First of all, we will analyze the feasibility of the research methods at the theoretical level and then design some type of microstrip leaky-wave antennas based on CRLH-TL; Finally, we simulate the model of antenna and then analyze the result of antenna model with the help of electromagnetic simulation software.The main contents are as follows: 1. The basic knowledge of the thesis, including the purpose of the topic and its socialvalue, the research status of metamaterials and microstrip leaky-wave antennas athome and abroad, the software of High Frequency Structure Simulator(HFSS). 2. The introduction of metamaterial. Firstly, the characteristic of metamaterialelectromagnetic propagation was deduced according Maxwell equations. Then, twophysical methods of realization metamaterial are introduced which are metalresonant structure and transmission line structure. Besides, two forms ofconstruction CRLH-TL are presented which are interdigital capacitor along withshorted stub inductance and metal-insulator-metal(MIM) capacitor along withshorted stub inductance. 3. The introduction of microstrip leaky-wave antenna. Firstly, the theory of leaky-waveradiation was deduced at the theoretical level and the characteristics of main beamscanning along with frequency is also analyzed. Moreover, we investigate thefeasibility of upgrading the beam scanning ability of metamaterial microstripleaky-wave antenna with the theory of CRLH-TL. Finally, the working condition oftwo methods of realization microstrip leaky-wave antenna-unit based on CRLH-TLare also studied with the software of HFSS. 4. The design and simulation of metamaterial microstrip leaky-wave antenna. Firstly,we design a microstrip leaky-wave antenna with interdigital capacitor along withshorted stub inductance and then improve the antenna unit for a smaller sizemetamaterial microstrip leaky-wave antenna. Secondly, we design a single-sideradiation microstrip leaky-wave antenna with MIM capacitor along with shortedstub inductance and then design a double-side radiation microstrip leaky-waveantenna which can scan in the whole space. Finally, We analyze the principle ofmicrostrip leaky-wave antenna and design an antenna whose main beam can scan ata fixed frequency at the theoretical level, which working by loading differentcapacitors to the antenna controlled by voltage. Then we simulate and verify thedesigns with the software of HFSS. |
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