Research On Optically Reconfigurable Antenna Driven By LED

Optically reconfigurable antennas controlled by Light-Emitting Diodes(LED) has been investigated in this paper, and the key point of this study is to verify the feasibility of utilizing small-size low-cost commercial light-emitting diodes(LEDs) to drive the optically controlled microwave switches(OCMS). Firstly, the microwave performances of the OCMS driven by LED are theoretically analyzed and measured by a vector network analyzer. Secondly, some effective measurements to improve the microwave performance of the OCMS driven by LED are discussed. Finally, an optically frequency reconfigurable antenna controlled by LED is designed, and this antenna can work at 2.4GHz and 2.8GHz.In chapter 1, the background, significances and developments of the OCMS and reconfigurable antennas are outlined, as well as the advantages and future of the LED. In the end, the structure and main work of this thesis are presented.In chapter 2, the working principle, analytic model, performance parameters and their factors are analyzed, and the luminous principle, electrical characteristics and optical properties of LED are also investigated detailedly. Then, the microwave performances of the OCMS controlled by LED are computed quantatively based on the photoconductive principle.In the chapter 3, the insertion loss and isolation of a silicon-based microstrip OCMS driven by different LED sources are measured and analyzed in a wide microwave band of 0.5-5 GHz. All of the measures are in the same optical power density. The driving sources are red, yellow, green, blue, purple and white LEDs, and the 980 nm laser is be used for comparison. In the end, an effective measurement is given to improve the insertion loss of the OCMS driven by LED.In the chapter 4, an optically frequency reconfigurable microstrip antenna is designed by using an OCMS driven by LED. This reconfigurable antenna can work at 2.4G and 2.8G by controlling the OCMS in different states.In the chapter 5, the summary about the research of the project and the expectation about the future work are presented.