The result shows that, the size of the coupling port has strong influence on the external quality factor of the output cavity, while the size of the coupling line and the capacitive metal rods mainly affect the tuning frequency of cutoff waveguide filter.

• 另外，由于耦合接头相当于在截止段中引人了一个附加电感，这使滤波器谐振电路的品质因数变大，谐振峰变窄。