A wideband antenna design method using eigenmode analysis: Application to a 300-GHz corporate-feed PCB slit array antenna

This letter presents a novel method for designing the radiating elements of a corporate-feed array antenna using eigenmode analysis. This approach numerically determines the eigenmodes, resonant frequencies, and radiation Q-factors of the radiating elements, enabling their evaluation without requiring impedance matching. A printed circuit board (PCB) slit array antenna structure was designed with three eigenmodes contributing to the primary polarization and low radiation Q-factors. Through parameter optimization, a 300-GHz-band antenna was designed, achieving a 24% bandwidth while satisfying manufacturing constraints of a PCB process. The proposed method offers a universal approach for realizing wideband performance in various antenna designs.