SIW based in-phase Gysel equal power divider for X-band application

This article presents a novel approach to designing fixed-width Gysel equal power divider (PD) in Substrate integrated waveguide (SIW) technology. Since the width and impedance of SIW are functions of its cutoff frequency, therefore, conventional Gysel PD design equations become non-applicable in SIW technology. Keeping this constraint, dependency of SIW line widths on operating frequency, novel design equations for the equal Gysel PD are derived for the fixed width line. Based on the derived equations, a circuit model of Gysel PD is developed, and the results are presented at 10 GHz. A simulation analysis of the proposed PD in SIW technology is carried out to support the theoretical analysis. Further, a prototype of the device is fabricated, and measurements have been done. From the experimental results, the reflection coefficients of all the ports are better than 15 dB, and isolation is better than 25 dB for the entire frequency band 9.5 to 10.5 GHz. The insertion loss varies between 1.88 to 3.28 dB in the operating band.