SIW Circuits with Dielectric Posts

Abstract

In Chapter 2, a method is presented to study a substrate integrated waveguide circuit with metallic posts inserted inside a homogeneous substrate. Although this type of circuit is the most widely adopted so far, a substrate integrated waveguide circuit with inhomogeneous substrate gives more freedom in the circuit design, and it may give some compact designs. This chapter generalizes the method presented in Chapter 2 to deal with a substrate integrated waveguide circuit with both dielectric and metallic cylinders. Herein, the field expression in each dielectric regions are required, and the boundaries conditions at all the material discontinuities including the boundaries of both metallic and dielectric cylinders should be enforced. The method is presented in a similar manner to that in Chapter 2, and two examples of inhomogeneous substrate integrated waveguide circuits are shown at the end of the chapter.