Lightning Protection for Mobile Phone Base Stations by Combining λ/4 Short Stub and λ/4 Open Stub

Abstract

This paper describes lightning protection for mobile phone base stations by combining quarter wave short and open stubs. MPBS (Mobile Phone Base Stations) have antenna towers and are often installed on the top of mountains. Therefore they have a high probability of lightning strikes.The most important lightning protection system is a bonding network and an earth system. All incoming services should be bonded at the entry to the MPBS in order to obtain an equipotential environment for all systems. And SPD (Surge Protective Device) should be installed at the entry to the BTS（ Base Transceiver Station）. As an SPD, either a GDT or λ/4 short stub was used. However, conventional SPD such as a GDT and λ/4 short stub cannot completely prevent the lightning surge current diverging to the BTS side. Therefore we have developed an insulated coaxial SPD that allows lightning surges to be discharged to the ground while passing signals without loss by combining the λ/4 short stub and the λ/4 open stub. The performances of this newly developed product were as follows. Insertion loss was less than 0.1dB, VSWR was less than 1.15 and voltage protection Level Up was 80V