A Research On Frequency Reconfigurable Antenna

Due to the explosion in demand for voice, data and video communication capacity in the Age of Big Data, application environment of modern communication system is complex and variable, we hope the radiation performance of the antenna can vary with the environment and reduce the waste of resources at the same time. So, reconfigurable antenna has excited widely attention and research. Reconfigurable antennas can alter the antenna’s radiation structure and generate multiple antenna function and by additional electronic devices or mechanical methods. According to different functions, there are four kinds of antennas: frequency reconfigurable, polarize reconfigurable, direction figure reconfigurable and multi-method hybrid reconfigurable. At present, this research field is still facing a lot of difficulties, such as how to simplify the bias circuit to reduce the influence of the bias circuit of the antenna. Therefore, the study of reconfigurable antenna has a strong frontier and exploratory.This dissertation focuses on the design technique of the reconfigurable antenna. The main contributions of this dissertation can be summarized as follows.1. A continuously tunable dual notched-band UWB antenna is proposed. Cutting two u-shaped slots in the radiation patch to generate dual band-notched characteristics at the central frequency at 3GHz and 5GHz, respectively. To change the slot equivalent length, two varactor diodes are placed in the middle of the u-shaped slots which controls the notched-band frequency, respectively.2. A discretely tunable sharp notched-band UWB antenna is proposed.Loading two resonators coupled to the feed-line generate sharp band-notched characteristics at the central frequency. To change the resonator length, two pin diodes are placed in the middle of the resonators which controls the notched-band frequency, respectively3. A novel bandwidth reconfigurable antenna is proposed, which can switch among three different impedance bandwidths by different condition of two PIN diodes to realize reconfigurable property.4. A bandwidth reconfigurable array antenna is proposed. Compared to a single antenna eleent, array antenna has a higher gain. Antenna prototype is successfully fabricated and measured. The measured results have a good agreement with the simulated results.