Research On Third Generation Passive Device And Leaky Cable Technology

Under the background that China will construct national 3G telecommunication system, this dissertation contributes to the optimization of the signal lightning protector and leaky cable for 3G system.The first part of this dissertation designs the lightning protector compatible for both 2G and 3G system. The design is theoretically analyzed thoroughly, properly modeled using transmission line model, and extends the original 1/4 wave length filter. Then using one of the most classic methods of inverse problem-conjugate gradient method to numerically analyze the model, and after repeatedly simulated and measured, the design successfully obtains the final parameter of the structure. The VSWR in 2G and 3G frequency band of the lightning protector is blow 1.12, which excels most of the other products in the market.The second part of this dissertation designs a new leaky cable which could be used in 3G. The design carefully analyzes the mechanics and modes of leaky cable, and combined the antenna array theory and genetic algorithm to search the parameter of leaky cable slots. After constructing a 3D model in simulation tool and abstracting the near field, the design derives the far field at 2m away from the cable with Huygens' Principle. The attenuation and coupling loss are both good enough to satisfy the requirement of 3G. This design is different from other products of foreign companies, and develops a new method to design leaky cables.Both of the two designs in this paper have some original innovation, and meet market's demands, so they are applicable and competitive.