AUTO-TUNING MICROWAVE FILTER

摘要

A microwave filter tuning arrangement comprises a directional coupler (DC) for coupling with an input line to a microwave filter (C1), so as to provide a first output (1) representing the power of a signal (f1) passing forwardly along the input line and a second output (2) representing the power of signals passing in the opposite direction along the input line, and means for combining the two outputs to form a control signal for tuning the filter. A 180 DEG phase shifter (PS) is provided for one of the outputs, giving the control signal an appropriate characteristic to provide closed-loop control to tune the filter (C1).