2016 Volume 13 Issue 4 Pages 20151120
This paper presents a novel compact in-line triplet substrate integrated waveguide (SIW) bandpass filter. The filter is composed of two SIW cavity resonators and an etched one-half wavelength grounded coplanar waveguide (GCPW) line resonator. The GCPW line resonator is etched between two SIW cavity resonators to obtain more compact size. A transmission zero on the upper stopband is created by the cross coupling, which allows the filter implementation in in-line with sharp upper cut-off skirts. Finally, a compact third-order 15 dB return loss filter with a fractional bandwidth (FBW) of 7% at 5.5 GHz is designed, fabricated and measured. The experimental results show good agreement between the simulated and measured results.