Uploaded December 2016 | Updated September 2026, 2 weeks ago
This short video illustrates an important tip to remember when tuning the center frequency of a cavity type bandpass filter, often used as part of a duplexer filter assembly. Using Return Loss instead of the Bandpass thru-loss characteristic will yield a more precise measurement of the filter's center frequency. Some analyzers have a directional coupler or return loss bridge "built-in", and some do not (like the one I am using in this video). In this latter case, an external directional coupler or return loss bridge can be used to measure the return loss.
This short video illustrates an important tip to remember when tuning the center frequency of a cavity type bandpass filter, often used as part of a duplexer filter assembly. Using Return Loss instead of the Bandpass thru-loss characteristic will yield a more precise measurement of the filter's center frequency. Some analyzers have a directional coupler or return loss bridge "built-in", and some do not (like the one I am using in this video). In this latter case, an external directional coupler or return loss bridge can be used to measure the return loss.
