The insertion loss and return loss of the coupled microstrip lines with
and without TL-shaped DMS are compared in Figure 12. By comparing the
results of simulation and measurement at the frequency of 0--8 GHz, it
is found that the insertion loss of etching TL-shaped DMS microstrip
lines and its adjacent microstrip line is better than unetched TL-shaped
DMS microstrip line, which proves that etch TL-shaped DMS can improve
the signal transmission ability of two adjacent coupled microstrip lines
and this is mainly due to the benefits of the suppression of far-end
crosstalk. The results of physical test and simulation cannot match
completely, which is mainly due to the accuracy of physical production
and unavoidable error of VNA, but the general trend is the same.