ABSTRACT
@#Introduction: For “smart health” Internet-of-Things (IoT) applications, substrate integrated waveguide (SIW) is a promising component to construct a wearable microwave device. For its efficacy in wearable devices, minimizing signal losses in terms of return and transition losses in SIW is of paramount importance. To enhance its performance, this paper presents the characterization of air-filled SIW transition losses for the SIW microwave device. Method: To investigate the effect of transition length on losses, the full-wave analysis of an air-filled SIW with different lengths of the taper transition was presented. For the analysis, the linear taper is designed for the Roger RT/Duroid 6002 substrate and utilized in the Ka-band frequencies. Result: From the full-wave analysis results, the length of the transition taper can be reduced considerably while achieving a wide-bandwidth characteristic of return loss better than 20 GHz. The results also show that the transmission loss can be reliably reduced while reducing the size of the SIW component. Conclusion: The findings may contribute to the development of the compact design of wearable microwave devices having a comparable performance with the conventional waveguide.