Substrate-Integrated Waveguide Impedance Matching Network with Bandpass Filtering

Abstract

A substrate-integrated waveguide (SIW) impedance matching network with bandpass filtering response is proposed in this paper. The first and last J inverters are affected by the termination impedances and its effect is proportional to the input or output external quality factors of the SIW filter. For validation of the proposed analysis, three-stage SIW impedance matching network with the $20-50 \Omega$ termination impedances is designed at center frequency (f0) of 8 GHz. The measured insertion loss is better than 0.9 dB at f0 and better than 1.3 dB from 7.62 to 8.31 GHz (FBW= 8.6%). The measurement results are in good agreement with the simulation results.