Reconfigurable Technique And Its Application To Antenna And Microwave Circuits

Nowadays, with the rapid development of the wireless technology applications and the increasing demands of the radio spectrum resources, the radio spectra have been nearly exhausted. In order to increase the efficiency of the limited spectrum resource,the thesis focuses on the reconfigurable technique and its application to an antenna and microwave circuits. After reviewing the recent research progress on reconfigurable technique, and combined with the requirements of the subject, three main structures are studied: a reconfigurable antenna, a reconfigurable filter and a reconfigurable power amplifier.Firstly, by reviewing the characteristics and practicability of the reconfigurable technique, advantages and disadvantages are discussed. Then classification of reconfigurable antennas is presented. The reconfigurable antennas according to the functions are divided into frequency reconfigurable antenna, pattern reconfigurable antenna, polarization reconfigurable antenna and multi-parameters reconfigurable antenna. This paper focused on the polarization reconfigurable antenna, since this kind of antenna allows the system to reuse frequencies and mitigate multipath effects.Secondly, based on the theory of the traditional filter, different implementation methods of reconfigurable filters are described, and a reconfigurable filter is developed. This filter features reconfigurable different passband, which can reduce the design cost and circuit size.Thirdly, after presenting the applications of reconfigurable devices in microwave circuits, reconfigurable switch for a dual-frequency power amplifier is studied. A new method for designing frequency reconfigurable power amplifier is given. The whole design process of this reconfigurable power amplifier is presented, where the reconfigurable frequency band is between 1800 MHz and 2400 MHz.Finally, work in the thesis is summarized and possible improvements are discussed.