Omar M. Alsalami

The authors present a novel self‐diplexing antenna (SDA) designed using substrate‐integrated waveguide (SIW) technology. The antenna features a planar‐backed cavity with a radiating slot and two input ports tuned to produce two resonances in the operating band for enhanced bandwidth. The design is simple and easy to implement, with similar radiation characteristics across the bandwidth. Experimental validation of the antenna shows good agreement with simulated matching, with two operating frequency channels in the X‐band (8.21−8.47 GHz and 9.42−9.764 GHz). The SDA's stable wideband performance makes it suitable for various wireless access points and applications. Overall, the study contributes a new SDA design with improved bandwidth and radiation features.