Abstract
This article presents a compact planar filtering antenna that integrates radiation and filtering functions within a singlelayer structure, providing an efficient solution for modern wireless systems. The proposed filtenna is based on a modified semi-hexagonal half-mode substrate-integrated waveguide (SH-HMSIW), which serves as the primary resonant cavity, enabling size reduction while preserving stable electromagnetic performance. To further enhance antenna characteristics, a via-loaded passive patch composed of two pairs of metallic vias is introduced as a secondary resonator. This resonator contributes to bandwidth enhancement and produces sharp filtering behaviour with improved frequency selectivity. By embedding the filtering functionality directly into the antenna structure, the requirement for external filtering circuits is eliminated, resulting in a compact configuration with reduced system complexity and fewer components. The inclusion of metallic vias enhances out-of-band attenuation and improves rejection performance, resulting in a well-defined passband and stable radiation characteristics. Measured results demonstrate that the proposed antenna achieves a high-realized gain of 8dBi along with a fractional bandwidth of 4.6%, confirming its suitability for contemporary wireless communication applications. The proposed design is novel in its integration of a modified SH-HMSIW cavity and a via-loaded passive patch within single-layer architecture, providing inherent filtering characteristics without the need for additional circuitry. Compared with existing filtenna designs, the antenna offers reduced physical size, enhanced gain, improved frequency selectivity, and simplified fabrication. The antenna performance is validated through electromagnetic simulations using ANSYS HFSS 2020, with simulated and measured results showing good agreement, demonstrating its potential for advanced wireless communication systems.
Keywords: Filtering Antenna, High Gain, Metallic Vias, SH-HMSIW, Substrate-Integrated Waveguide.