A Gain Equalizer Based on Dual-Mode Circular Substrate Integrated Waveguide Resonators

A microwave gain equalizer (GE) with good tunability, high Q factor, and compact volume for Ku-band application based on dual-mode circular substrate integrated waveguide (SIW) resonators is proposed. The characteristics of two orthogonal coupled slots to excite the dual modes are presented, and the optimal position of thin-film resistor to tune attenuation has been investigated. The resonant frequencies and attenuations of the dual-mode can be tuned independently, and the GE is easily fit to a required attenuation curve. For demonstration, the GE is designed and fabricated, and measured results agree well with simulated ones.