Application Of Genetic Algorithm In The Design Of Broadband And Multiband Microstrip Antenna

The rapid development of mobile communications technology promotes the mobile terminaldevice to the evolution of miniaturization and multi-function. The original narrow-band antenna hasbeen unable to meet the requirements that equipment miniaturization and multi-working frequencyin modern communication technology. The microstrip antenna with its advantages of small size,light weight, appearance diversity and easy to integrate has been attracted widespread attention inmobile communication field. This paper aims at the research of the multi-frequency and broadbandin microstrip antenna. The thesis will do some exploration on the optimization in the microstripantenna at the same time.This thesis expounds the basic theory of microstrip antenna and its analysis methods, and givesa summary about the bandwidth and multiband techniques of microstrip antenna. This thesis alsointroduces the characteristics of genetic algorithm and its basic operation. In view of theirrespective advantages of Genetic Algorithm (GA) and High Frequency Structure Simulator (HFSS)software, the thesis introduces the design of the mixed optimization program for GA and HFSS. Theprogram is realized under the environment of Matrix Laboratory (MATLAB). Based on the program,the optimization design and simulation analysis of broadband and multiband antennas arecompleted.The program is used to optimize the structure of microstrip antenna at the basis of S11. Usingthis method, the thesis, which focuses on the design in broadband and multiband antennas, not onlydesigns three novel microstrip antennas, but also analysis the effects of main parameters of theantenna structure. The first paragraph of the antenna is feed by coplanar waveguide, and owns ahexagon patch as radiation. It has a wide frequency range from 3GHz to 12GHz. The others, owndual-band or tri-band characteristic, can be applied in wireless communication system such asWLAN and WiMAX. The dual-band antenna has an irregular E shaped radial patch, and realizes thebroadband in the low and high frequency (impedance bandwidth is about 24% and 46%respectively). Loading double U-shaped slots in the first paragraph antenna, the third antennarealizes triple bands. In order to validate the results of optimization and simulation analysis, theantennas are fabricated and measured by vector network analyzer (VNA). The measured results areconsistent with the simulation results, which verify the correctness and feasibility of theoptimization program.