Mobile Terminal Pattern Reconfigurable Antenna Design

In recent years, MIMO communication systems are developing fast, and show great advantages at improving system capacity and communication speed. Antenna is an important part of MIMO communication system, and its proper design can optimize the system. At the same time, as the mobile terminals become miniaturized and multi-functional, the requirements to antenna performance are increasing. Gradually, the traditional simple antenna can hardly satisfy the requirements in wireless communications. So, with limited space and energy, and variable channels, how to design the qualified reconfigurable antennas on mobile terminals to meet the requirements of future wireless communication is a problem worthy of research. In this paper, pattern reconfigurable antennas for mobile terminals application are researched.First in chapter one, the background, the significance and the development sketch of reconfigurable antennas is briefly introduced. In the second chapter, some basic concepts and theoretics that are related to the antennas in this paper are introduced, including antennas parameters, theoretics and development of microstrip antennas and the briefly introductions of MIMO technology.Then, in the third chapter, pattern reconfigurable antennas for notebook PC application are presented. Based on the PIFA structure, a pattern reconfigurable antenna can be controlled by RF diode switch is designed, with bandwidth expanded at the same time. Then based on this design, varactor diode is adopted in the reconfigurable antenna, and continuous alteration of antenna pattern and gain is achieved. At last, the designed reconfigurable antennas are applied in notebook PC, and antenna parameters and MIMO communication tests are finished. The experiment results are good, proving the fact that pattern reconfigurable antennas can optimize the communication system.Secondly, pattern reconfigurable antennas as well as two-element array which can be used in handheld mobile devices are presented in the fourth chapter. A basic pattern reconfigurable antenna and control circuit are designed with monopole antenna structure. Then two structures derived from this antenna are designed. One can realize pattern reconfiguration at single band, while frequency reconfiguration can be achieved at the same time. The other one can realize pattern reconfiguration at three bands simultaneously. By careful simulations and tuning, we get good achievements.Integrated with actual devices, several pattern reconfigurable antennas and relevant arrays are designed in this paper. By simulations and tests, satisfied results are received. These antennas have good prospects in actual applications.