Design and Construction of a Low Loss Substrate Integrated Waveguide (SIW) for S Band and C Band Applications

Substrate integrated waveguide (SIW) technology has immense applications for the design of microwave components and devices. In this paper, a low loss substrate integrated waveguide (SIW) structure is designed, fabricated and experimentally tested to exploit in S band and C band applications. SIW structures are constructed by interconnecting parallel metallic surfaces with two rows of metallic vias embedded in a dielectric material. In comparison with rectangular waveguides, SIW inherits better wave guiding characteristics. Substrate integrated waveguides feature a lightweight, minimal-loss, versatile, and cost-effective approach for circuit component integration over the same substrate. The presented SIW structure is designed using RT/Duroid 5880 material, which has dielectric constant, epsilon(r) = 2.2, dissipation factor, tan delta = 4 x 10(-4) and height h = 0.508 mm. The insertion and return losses measured using vector network analyzer are 0.95 dB and 23 dB, respectively. Simulated and measured results are in close agreement with each other with slight variation. The insertion loss (S-21) and return loss (S-11) have uncertainty values of 0.51 dB and 2 dB, respectively. Suggestions for future research are also presented with an emphasis on the use of advanced materials in SIW systems for high-frequency applications with limited losses.