Design SIW iris bandpass filter at 18GHz

This paper shows rough procedure to design Substrate Integrated waveguide (SIW) bandpass filter. The center frequency is at 18GHz, and the bandwidth is about 1GHz. After calculating [K/(Z0)] of K-inverter, we can substitute parallel inductor and transmission line for K-inverter. Finally, using curve fitting analysis to find the relation between iris window(W) and the inductor. The SIW bandpass filter at 18GHz have been design through these procedures.