Optimization Design Of Muti-band Wilkinson Power Divider By The Method Of GA And PSO

In recent years with the rapid development of modern wireless communication and multi-band microwave transmission system, power divider as one of the most important passive devices in modern radio frequency communication system, the WPD for distributing and combining transmission signal power has been widely used. with the development of multi-band communication systems, traditional single-band WPD has not been able to meet the transmission demand, so the design of multi-band WPD has very important value of practical, the genetic algorithm and particle swarm algorithm as the optimization algorithm lead into the process of designment, the result shows that not only reduce the tedious calculation formula derivation process, but also improve the design efficiency and accuracy.Firstly, the paper introduces the development background of Wilkinson power divider, and the genetic algorithm and particle swarm algorithm are outlined. The fundamental and basic characteristics of the Wilkinson power divider are described. Basic transmission line theory is introduced in dual-band Wilkinson power divider design, the formula derivation of the dual-band power divider is presented using odd-even mode analysis, and the design parameters are presented.Further more detailed formula derivation of multi-band Wilkinson power divider is analysed, some tri-band, quad-band and penta-band Wilkinson power dividers design are given and the parameters and simulation results related under a variety of different frequency requirements are presented, the simulation results show the design achieve ideal match point in the design frequency.Then the frequency-dependent impedance in the actual RF circuits is studied, the odd-even mode method is used to analyze the design of multi-band frequency-dependent Wilkinson power divider, a tri-band frequency-dependent WPD is designed and simulated. The problem of harmonic interference problems will appear in the case of design frequency span is too wide. through reforming impedance converter structure and using genetic algorithm optimization a good harmonic cancellation is achieved.At last the tri-band and quad-band Wilkinson power divider are layout designed and physical produced, the result is tested and measured by a vector network analyzer, all of the above simulation results agreed well with experimental data and have a good matching at the required frequency, validity and effectivity of the genetic algorithm and particle swarm algorithm has been testified and proved.