A preliminary result on development of analog broadband tapped delay line for L-band applications

This paper presents a brief comparison of delay line elements to develop a tapped delay line system. The comparative study includes surface integrated waveguide (SIW)-based delay line elements and coaxial cables. For SIW-based delay line elements, we divide the analysis into two scenarios based on the used transition line configuration, namely microstrip-to-SIW transition and grounded coplanar waveguide (GCPW)-to-SIW transition. This transition line is required to ensure impedance matching between transmission line and SIW component. Based on numerical analysis, it can be seen that the return loss of a SIW-based delay line with microstrip-to-SIW transition is better than the one with GCPW-to-SIW transition. Furthermore, the time delay of SIW-based delay line with microstrip-to-SIW transition is longer than the one with GCPW-to-SIW transition. In addition, for the whole design of 6-taps delay line system, a flat time delay of around 1 ns is achieved which reasonable insertion loss and isolation between two neighboring taps.