Research On The Wide-band Leaky Coaxial Cable For Mobile Communication

Leaky Coaxial Cable(LCX)is a kind of coaxial cable which has the period slots on the outer conductor,and gets the function of radiation,reception,and transmission.Because of the extraordinary structure and radiation characteristic,it has the extensive use in the signal cover of especial area,such as tunnel,mine,high-rise buildings,and so on.In this thesis,the leaky coaxial cable which used in special areas is mainly discussed,based on the research project “Research on the Coupling Loss Theory of Leaky Coaxial Cable”.Begin with the development tendency of the leaky coaxial cable,a brief introduction on the structure of the LCX,the main functional parameters and the classification of the LCX are mainly discussed.With the radiation characteristic of single inclined slot on outer conductor,the vertical polarization LCX and horizontal polarization LCX are designed.And based on the theory of that the circularly polarized wave can be compounded by orthogonal linearly polarized wave,a circular polarization LCX is designed by using the slots which can generate vertical polarized wave and horizontal polarized wave,respectively.The results of the LCX by HFSS show that the LCX have realized the specific polarization at the maximum radiate direction.And the LCX which designed can be used in the signal cover at the specific areas.The means of suppressing the highly radiation harmonics by cutting unequal distance new slots are researched in the thesis,as well as the resonance characteristic of the LCX.The results of circular polarization LCX by HFSS show that the-2 harmonic has been suppressed,and the coupling loss get 4dB and 2dB improvement at the frequency of 1800 MHz and 2400 MHz,respectively;For vertical polarization LCX,the-3 harmonic has been suppressed,and the coupling loss get 4dB and 4dB improvement at the frequency of 1800 MHz and 2400 MHz,respectively;For the LCX with inclined slots,the-2 and-3 harmonics have been suppressed simultaneously,and the coupling loss get 11 dB and 12 dB improvement at the frequency of 1800 MHz and 2400 MHz,respectively.