Mode-Matching Analysis of Phase Shifter in Substrate-Integrated Waveguide Technology

As essential parts in phased array antennas, phase shifters are often realized in substrate-integrated waveguide (SIW) technology in order to satisfy the requirements of low cost, low loss and easy integration with other planar circuits. This type of SIW-based structure can be efficiently modeled with the mode-matching method (MMM), which offers advantages of high precision and high computation speed. For illustration, in this paper, the method is applied to an SIW phase shifter operating at 7.5GHz defined by two cylindrical posts in the waveguide. Since the phase shifting function is introduced by adjusting these cylindrical posts, the relationships between the phase shifting capability and the diameters and positions of the posts are investigated within the specification of a return loss better than 15dB. All mode-matching analysis results are validated by fullwave finite-element simulations using Ansys HFSS.