Dual mode bandpass filter using trefoil torus knot resonator

In this paper we present compact dual mode band pass filter based on trefoil torus knot resonator. The resonator is realized using additive manufacturing technology. Size of the resonator is 0.16 λ at the center frequency of operation. Fabricated resonator prototype is about half the size of ring resonator. Simulated and measured results are presented which are in good agreement.