Miniaturization Techniques of Substrate Integrated Waveguide Circuits

Substrate integrated waveguide (SIW) has become popular and it has widely been used in microwave and millimeter wave circuit and system designs. Compared to other planar transmission lines, the geometrical dimension, in particular, the width of an SIW is much larger, which depends on the operating frequency and substrate material. Therefore, an effective SIW miniaturization is required for developing a high-density integration in circuit design. In this paper, three miniaturization techniques of SIW circuits are discussed in order to achieve a high compression ratio. A group of SIW transmission lines based on these miniaturization techniques are analyzed and their propagation constants and quality factors are extracted for comparison.