Frequency-Tunable Substrate-Integrated Waveguide Filter Using Contactless Rotatable Flaps
This paper introduces a substrate-integrated waveguide (SIW) filter that can be tuned using contactless rotatable flaps. There is no mechanical contact between the tuning flaps and the filter body, and this gives a number of advantages in frequency tuning since the flaps do not experience any friction. In addition, it can be tuned with little power consumption, while maintaining stability. Periodic mushroom shaped pins are formed in the flap so that the field generated in the resonator does not leak. Therefore, the Q-factor of the resonator does not decrease even though the flaps are floating in the air. A third-order SIW filter was fabricated and measured for verification. The center frequency is from 2.66 GHz to 3.34 GHz and the insertion loss varies from 0.79 dB to 0.88 dB.