Ku Band Continuously Tunable Circular Cavity SIW Filter With One Parameter

This letter introduces a Ku band continuously tunable filter with one parameter. The proposed filter is implemented using substrate integrated waveguide (SIW) technology and has a simple and symmetrical structure. The tunability of the circular resonator is a kind of mechanical tuning, achieved by the different distance between moving copper column and the center of the circular cavity. Location of moving distance has an approximately linear relation with the dominant cavity resonance frequency. The single circular cavity has a tuning range of 12.6–15.0 GHz. The fabricated filter is made up of two cavities and has a frequency tuning ratio percentage of 19.2% compared with the center frequency 13.825 GHz. The insertion loss is between 1.7 and 2.8 dB.