Research And Design Of Optically Controlled Pattern Reconfigurable Antenna

With the capability to change the radiation characteristics flexibly,reconfigurable antennas will become indispensable parts for the next-generation wireless communications and sensing systems.In this thesis,optically controlled microwave switch(OCMS)and its applications in pattern reconfigurable antenna have been investigated.Several pattern reconfigurable antennas are designed by using the optical microwave switch.The main work of this thesis is as follows:1.A electronically controlled pattern reconfigurable Quasi-Yagi antenna based on phase tunable is designed for wireless local area network(WLAN)at 5.3GHz.The antenna operates at three states with the xoy-plane maximum beam direction towards ? =0° and ? =±13°,respectively.The gain of the antenna is 9.2d Bi?10.2d Bi at three states.Then,the PIN diodes of the electronically controlled antenna are partially or completely replaced by the OCMS,and two optically controlled pattern reconfigurable Quasi-Yagi antennas are designed respectively.The antenna which only the PIN diodes of the director part are replaced by the OCMS,has a good pattern reconfigurable characteristic as well as the approximate gain as the electronically controlled antenna in the three modes at 5.3GHz.This design not only simplifies the complex bias circuit,but also avoids the deterioration of the antenna performance.2.A Quasi-Yagi antenna works at 5.5GHz with switchable pattern is designed.The maximum beam direction of xoy plane of the antenna can be switched between = 0 ° and = ± 90 ° by switching the light and dark state of the OCMS.The simulation results are in good agreement with the test results.The test results show that the antenna gain of the three modes is 4.9d Bi ? 5.2d Bi.As a contrast,the microwave PIN diode is used to replace the OCMS,and the same pattern switchable antenna is designed,manufactured and tested.The results of simulation and measurement show that the gain of optically controlled antenna is 2.6d Bi less than that of electronically controlled antenna.Therefore,we study the influence of the light state and dark state conductivity of the OCMS on the antenna gain.The results show that when the light state conductivity of the OCMS is greater than 1000S/m and the dark state conductivity is less than 0.1S/m,the gain of the optically controlled antenna is basically the same as that of the electronically controlled antenna.