Design And Implementation Of Broadband Leaky Coaxial Cable

Leaky coaxial cable is a kind of coaxial cables of which the outer conductor has slot structure. It has an ability of signals transmission and can radiate or receive signals, and it has dual functions of both transmission line and antenna. Because of its environmental adaptation ability, low loss, signal coverage uniformity, strength stability and other advantages, it is not only widely used in closed or semi-closed space requiring high-quality signal reception such as tunnels, subway, underground parking, elevator, and so on, but also applied to the growing concern for the security field.Aiming at the application requirements of broadband leaky coaxial cable for subway, highspeed wireless communication system, according to the standard of communication industry YD/T2491-2013, the theoretical basis of leaky coaxial cable is elaborated. Four kinds of leaky coaxial cables with different slot structures such as L-shaped, U-shaped, ?-shaped and eight slot are designed. And the electromagnetic simulation model of leaky coaxial cable based on the three-dimensional electromagnetic simulation software HFSS is built.Taking the main electrical performance index of leaky coaxial cable as the research objectives, so the effect on coupling loss and transmission attenuation of sub interval and slot size parameters is simulated and analyzed at the different operating frequencies by using electromagnetic simulation software. The characteristics of transmission attenuation and coupling loss of leaky coaxial cable of which the outer conductor has L-shaped, U-shaped and eight slot are optimized at operating frequency of 900 MHz.The U-shaped and ?-shaped leaky coaxial cables are designed and implemented. The transmission attenuation and coupling loss of them are measured by sample testing, and the measured and simulated results are in good agreement. The characteristics of U-shaped and ?-shaped leaky coaxial cables satisfy the standard requirements of the wireless communication system by electromagnetic simulation analyzing and sample testing.