High-Q planar active resonator based on substrate integrated waveguide technique

A low-cost planar active resonator in Ku-band based on the substrate integrated waveguide (SIW) technique is reported. A series feedback network is used to generate the negative resistance, which compensates the energy loss within the SIW cavity. The quality (Q) factor of the SIW resonator is greatly improved. An experimental active SIW reflective-resonator is designed and fabricated. The measured results show that the proposed active resonator possesses a loaded Q factor of 1455, and unloaded Q factor of 7631, which is ultra-high among other planar resonators. The active SIW resonator is a promising element for the design of high-performance microwave filters and oscillators.