Properties of parallel-plate stepped variable-impedance lines

The operating principle of stepped transmission lines is introduced, and an ideal rule of output voltage in quasi-Blumlein lines is given. The stepped transmission lines can completely transmit energy and increase the voltage to (n+1)/2 times the input voltage. Also impedance deflection in the stepped transmission lines is researched. The actual impedance is a little bigger than design value, and the impedance deflection ranges from 0 to 20%. By electromagnetic simulation, the relations of impedance deflections and output voltages in three-grade stepped transmission lines are given. In the range of impedance deflection, output voltage coefficient increases with the decrease of impedance, and it ranges from 1.9 to 2.1. The effect of output voltage on transmission lines impedance deflection is discussed. At last, a three-grade stepped transmission line is designed and its experimental results show that the theoretical and experimental data are in good agreement.