Advanced Member level 3
While moving small copper foil piece along microstrip line I observed how noise/power levels depend on chosen position, and how their maximum repeat each few millimeters. And then i come to conclusion, that signal noise/power pattern repeats each half wavelength. As i understand it is because of half-wavelength impedance repeating, so adding stub at half wavelength apart gives similar noise levels. So i measured three maximums in noise/power and marked their position on PCB. For given line width and substrate Er calculations i have wavelength in dielectric of 15.08mm. Distance between first and third marker marker position is 15.3 mm. Looks like real wavelength in dielectric is measured! Correct me if i am wrong. Also making longer line can give more precise result, as we can measure, for example 5-10 wavelengths. I must also say that line is well-terminated. Please comment.