Investigation of operational range of SIW transmission line by varying via shape at X-band

Substrate integrated waveguide (SIW) is a new form of transmission line which can be easily integrated into the substrate of planar circuits. SIW are designed by means of taper transition for matching with planar microstrip line. This paper presents the prediction of operating range of Substrate integrated waveguide at X band. The effect of change in diameter, pitch of metallic post has been observed for proposing the operational range. Conventional cylindrical via has been complied with square via as a new design methodology. The results obtained with cylindrical via show an effective bandwidth of 20% having 20dB return loss and 0.5 dB insertion loss whereas with square via 47.5% at 20 dB return loss with 0.7dB insertion loss has been achieved.