Investigation of integrated filter-antenna based on cascaded and multilayer approaches

A novel design of an integrated single-mode substrate integrated waveguide (SIW) bandpass filter and microstrip patch antenna is presented. To realize the concept, an SIW filter and a patch antenna were combined using cascaded and multilayer technologies on a microstrip structure. The design is based on the single-mode rectangular cavity structure using TE₁₀₁ mode for SIW filter and TM₀₁₀ mode for the antenna. To validate the design technique, SIW filter and patch antenna can be designed on the same planar structure using the cascaded technique, while the foam layer of the filter and the antenna can be designed using the multilayer approach. The experimental performance shows good agreement with the return loss level, better than 10 dB in the passband region. This investigation provides an alternative solution for integrating filter and antenna subsystems particularly in any wireless communication systems.