Dispersion and Dielectric Effects on Reflection and Transmission of Electromagnetic Waves Propagating in Multiple Stages of Tape-Helix Blumlein Transmission Lines

Abstract

Abstract-Tape-helix transmission lines and helical coils have important applications in communication technology, signal measurement, pulse delay, pulse forming and antenna technology. In this paper, a set of fully dispersive propagation theory based on matrix method is firstly introduced to explain the propagation characteristics of travelling electromagnetic waves in multiple stages of helical Blumlein transmission lines with finite lengths. The different stages of helical transmission lines are filled with different propagation dielectrics, and the effects of dispersion and dielectrics on the propagation matrix and S-parameter matrix of the travelling waves are analyzed in detail. Relations of the exciting current waves in the series-connected helical Blumlein transmission lines are studied, and the dispersive transmission coefficients and reflection coefficients of electromagnetic waves at different dielectric ports are also initially analyzed. As an innovation, the proposed fully dispersive propagation theory which was demonstrated by simulation and experiments can substitute the non-propagating tape-helix dispersion theory and the non-dispersive telegraphers' equation to analyze the helical transmission lines.

Effects of the Inductive Port of Blumlein Transmission Line on the Reflection and Transmission Characteristics of Electromagnetic Waves

“…Under the mechanisms of traveling wave reflection, transmission and the vectorial superimposition of waves, a quasi-square voltage (current) pulse can be formed on the load at the terminal port of the BTL. As a result, the BTL is an important technology for high-power square pulse generation, pulse shaping and modulation [15,16]. Figure 1(a) shows the typical pulse modulation schematic based on a BTL and a saturable pulse transformer (SPT) [19,20].…”

“…The wave reflection and transmission coefficients at the port of a common non-dispersive TL are only determined by the port impedances [13,14]. However, the dispersive propagating theory of traveling waves reveals that those coefficients aforementioned are determined by the port impedances, dielectric characteristics and work frequency [16]. The common concerned wave reflection cases of the TL include 3 types such as wave reflection at the joint port of TL-TL [13], or at the joint port of TL-resistor [11], or at the joint ports of TL-resistor-TL [14].…”

“…Every TL has its own characteristic impedance, and the impedance of a dispersive TL changes in line with the work frequency [15,16]. A practical TL has a finite length so that the propagating electromagnetic wave reflects and transmits at the terminal ports of the TL [16][17][18].…”

“…The common-used switches include the trigger switch, semiconductor switch, spark gap switch [13,14] and magnetic switch [11,16]. When the switch is open, the TL port of the switch is also open with an infinitely large impedance.…”

“…In many applications, a switch is required to connect with the TL port [11][12][13][14][15][16], in order to control the propagating courses of the electromagnetic waves. The common-used switches include the trigger switch, semiconductor switch, spark gap switch [13,14] and magnetic switch [11,16].…”