X-band substrate integrated waveguide (SIW) filter design with transmission zeros

Abstract

This thesis details the design and development of an X-band filter based on Substrate Integrated Waveguide (SIW) technology. SIW technology is introduced as an alternative to overcome some drawbacks of a planar structure (such as microstrip) and non-planar structure (such as metallic rectangular waveguide), as it combines the best aspects of the two technologies. SIW filters are low cost, compact and easy to integrate with other devices. The basic concept of SIW merges waveguide cavities’ planar structures on a single dielectric high-frequency material. This is accomplished through two rows of metalized via holes in the dielectric substrate that are in between two parallel metal plates acting as the walls of the waveguide cavity. Two design methods used to design and develop a fourth-order SIW filter are presented in this thesis. The developed SIW filter is for an X-band transmitter that will be used in a cube satellite that is developed at the French–South African Institute of Technology (F’SATI). The SIW filter is designed to have a passband ranging from 8.025 GHz to 8.425 GHz with transmission zeros at the local oscillator frequency band (6.8 GHz to 7.2 GHz) and image frequencies (5.575 GHz to 6.025 GHz). The SIW filters are fabricated using the in-house Printed Circuit Board (PCB) prototyping machine. The measured results are in good agreement with the simulated results, hence the measured results showed that the designed SIW filters meet the filter specifications.