Design of Dual-Band Filtering Antenna Based on 3-D Printed Half-Mode Gap Waveguide Quadruple-Mode Resonator

In this letter, a high-selective dual-band filtering antenna for millimeter-wave application is first proposed based on a half-mode gap waveguide quadruple-mode resonator. Four resonant modes are simultaneously excited within a single cavity following the transversal hybrid electromagnetic coupling topology, thus forming dual-passband filtering characteristics. Three radiation nulls are generated on both sides of two passbands due to the created bypass coupling and can be controlled independently. A stacked radiating cavity with shared aperture provides uniform polarizations for dual-frequency application. For experimental validation, 3-D multijet printing technology was used to fabricate prototypes integrally, significantly reducing the assembly loss. The final measured results agreed well with the simulated ones.