Design of a Three-Mode Dielectric Waveguide Filter with Flexible Transmission Zeros

In this paper, by inserting two tuning blind holes on the side of the dielectric waveguide resonator, a three-mode resonator is formed; by changing the positions of the two tuning blind holes on the side, a capacitive or inductive CT coupling structure is formed in the three-mode resonator; and, finally, by using three-mode resonators, three six-order dielectric waveguide filters with different transmission characteristics are designed, which verify the feasibility of the design.