Miniaturised ISM band HMSIW band-pass filter loaded with wide U slot

摘要

In this study, two half-mode substrate integrated waveguide (HMSIW) filters are proposed by introducing wide U slot in the conventional SIW (substrate integrated waveguide) structure. In the first case, lower ISM (industrial, scientific and medical radio) band HMSIW filter is designed by extending the centre stub, thereby controlling the resonant frequency and bandwidth. In the second case, higher ISM band HMSIW filter is designed by shorting the extended stub using via. These filters are having a compact core size of 26 mm ?? 11 mm and work at 2.4 and, 5.8 GHz with a fractional bandwidth of 4.0 and 2.6%, respectively. The filter is fabricated with a single layer standard printed circuit board process. The measured results are good and in agreement with simulated results. The band-pass filter structure has the advantage of low insertion loss, good return loss, sharp side band rejection and compact size.