Half-Mode Slow-Wave Substrate Integrated Waveguide Analysis

Abstract

Abstract-Design of a compact Substrate Integrated Waveguide (SIW) transmission line is presented in this paper. The main parameters of SIW were parametrically studied, and final designed component was fabricated and measured, which showed very good matching (near 90%) with simulations, demonstrating significant miniaturization factor. The miniaturization was done using Half-Mode (HM) and Slow-Wave (SW) principles together. It was found that the HM-SW method for SIW miniaturization reduced the SIW surface area with a remarkable factor value (70%) while maintaining acceptable characteristics compared to the original SIW. In fact, HM technique reduced 40% the lateral dimension of the SIW, and using the SW technique allowed 30% of size reduction added to the HM principle. Furthermore, a proper microstrip to HM-SW-SIW tapered transition was designed, which showed a return loss decrease between 3 dB and 7.5 dB, as well as facilitating measurement. On the other hand, the proposed transmission line could lead to a size reduction of 30% compared to the HM-SIW miniaturization technique. The HM-SW-SIW transmission line concept presented in this paper can be used to design other compact SIW components such as bandpass filters, couplers, and power divider.