The Research And Design Of Multi-frequency Reconfigurable Antenna

Reconfigurable antenna has a strong exploration in the antenna study and the trend of antenna development in the future. Different from the traditional antennas, reconfigurable antenna can be expanded at the resonance and radiation performances by loading electronic components and other methods to change the antenna structure. Such antennas with multiple antenna functions, can reduce the quantity of antennas which are equipped with wireless communications platform, and also can simplify its complex electromagnetic radiation environment. It has broad application prospects in the requirements of high-speed, large-capacity for contemporary wireless communication.This paper focuses on topic of the multi-frequency reconfigurable antenna, the main research content and results of the work are as follows:Firstly, the current situation of modern wireless communication is introduced, and the research and development of reconfigurable antenna is of great significance. It introduced the classification of reconfigurable antenna, and common methods for various types of reconfigurable antenna achievement. The basic theory of antenna radiation and the basic parameters of the antenna which are the standard of antenna measurement both are illustrated, as well as commonly used electromagnetic simulation software and FEM electromagnetic numerical methods.Secondly, simulated and analyzed the equivalent model of the diodes which are taken into account in the design of reconfigurable antenna, and the issues of performance on antennas as the DC bias put on. Designed and produced a multi-band frequency reconfigurable antenna which is different from the conventional single-band tuning antenna, it can be reconstituted in three different frequency bands. The single-band of center frequency in 2.4GHz, the dual-band of center frequency in 2.4GHz and 3.5GHz, and the Tri-band of center frequency in 2.4GHz, 3.5GHz and 5.8GHz. Use upper and lower surfaces of the dielectric substrate, with the embedded PIN diode switches in the substrate, the number of diodes is streamlining and the DC bias network is simplified.Finally, designed and produced a dual-frequency and pattern reconfigurable antenna. using the same structure of radiating elements in different directions, can integrate and reconstruct its performance in the pattern reconfigurable ability, Under this premise, loading the PIN diodes on its radiation elements, make it has a frequency adjustment function. The antenna can be adjusted in the center frequency of single-band in 3.5GHz and 5.8GHz respectively, and dual-band of center frequency in 3.5GHz and 5.8GHz. It has the pattern reconfigurable ability in 3.5GHz of the dual-band. Designed and fabricated a highly symmetric structure reconfigurable antenna, its radiating elements are surround the coaxial feed, symmetrical structure has the outstanding performance in pattern reconfigurable ability, it has three different orientation patterns on single band frequency. On this basis, according to the pattern similarity in this phenomenon, reduce its structure while the number of PIN diodes is decreased, the complexity of its DC bias is lowered in the network. At the same time, the half-cut antenna maintains its single-band frequency of 2.6GHz with two patterns and results in a new frequency.