A compact bandpass filter using quarter SIW cavity resonator with source-load cross coupling

A novel source-load cross-coupling bandpass fillter using a quarter substrate integrated waveguide (SIW) cavity resonator is presented in this paper. Compared with the conventional SIW cavity resonator, the size reduction of the new filter is up to 75%. The resonator is realized by a rectangle patch shorted by two right-angle metallic lines via holes. The dominant resonant mode of the proposed resonator is TE₁₀₁ mode. The proposed filter shows a 6.2% fractional bandwidth at 3.5 GHz with a return loss of better than -21 dB and an insertion loss of less than -2.1 dB.