Bandwidth tunable waveguide-bend filter using the C-slit diaphragm

We propose a waveguide-bend filter with C-slit diaphragm for the highly tunable bandwidth. Through changing the position of the C-slit at the bending corner, the fractional bandwidth properties are shown to be capable of varying from 0.3 to 40.8%. Full wave simulations and the equivalent circuit model are both presented to interpret the transmission performance of such a waveguide-bend filter and the results are consistent with each other very well in predicting the highly tunable bandwidth. Finally, we carry out the experiments to verify our proposed design and demonstrate that the bandwidth of the waveguide-bend filter can be tuned widely from 0.07 to 4.2 GHz in the X-band.