Analysis of the Strong Reflection Points of the Serpentine Micro-Coaxial Delay Line

In this study, an analysis is conducted on the strong reflection points (SRPs) of a serpentine micro-rectangular-coaxial delay line (MRCDL), to reveal the origin. It is disclosed that the SRPs are caused by the residual crosstalk at the bends between the adjacent segmental lines. The SRPs still exist and are stronger in the higher frequency band, and the periodicity is still related to the electrical length of the segmental lines, as in the conventional microstrip delay line. Even though the coupling strength between the adjacent segment lines in the MRCDL is greatly weakened comparing to the conventional serpentine microstrip delay line. The analysis gives us a caution that the SRPs are still needed to be avoided in the design of the MRCDL, which can be realized by adjusting the delay line pattern.