Theoretical and experimental research of a folded parallel-plates Blumlein line

In this paper a Blumlein line in folded parallel-plates configuration using Kapton film as dielectrics is investigated.The characteristic parameters of this Blumlein line were analyzed theoretically,and the electromagnetic field distribution and the process of the wave transmitting in the transmission line are simulated.According to the results of the theoretic analysis and simulation,a Blumlein line in folded parallel-plates configuration with output voltage of 600 kV,pulse duration of 40 ns,characteristic impedance of 5 Ω was designed and manufactured.The chamber of the Blumlein line is 1.2 m long,0.4 m wide and 0.4 m high.The experimental results demonstrated the wave transmitting process in Blumlein line and gave the voltage waveform of 400 kV and the current waveform of 40 kA with a pulse duration of 36 ns.Another folded Blumlein line with output voltage of 600 kV,pulse duration of 150 ns,characteristic impedance of 15 Ω was designed and set in the same chamber.The experimental results gave the voltage waveform of 450 kV and the current waveform of 18 kA with a pulse duration of 150 ns.Engineering problems such as the edge electric breakdown and the measurement precision by a resistance divider were revealed,which must be solved in later work to manufacture more compact transmission line.