A miniaturized linear Yagi–Uda antenna array with enhanced gain for sub-THz wideband communication

This paper presents a miniaturized linear Yagi–Uda antenna array designed to deliver enhanced gain for wideband operation in the sub-terahertz (sub-THz) frequency regime. Realized on a Rogers RT5880 low-loss substrate with a compact footprint of 5.6 × 9 × 0.127 mm3, the array structure incorporates a linearly arranged driven element, multiple parasitic directors, and a reflector plane to achieve strong end-fire directivity. The antenna array operates continuously across 136.88–156.82 GHz, sustaining a return loss greater than 10 dB over the entire operating band. The linear arrangement of director elements promotes progressive inter-element electromagnetic coupling, which collectively enhances the far-field gain performance. The array achieves a simulated peak gain of ∼12.5 dBi along with a radiation efficiency exceeding 92%. A thorough parametric study is conducted to assess the impact of substrate permittivity, substrate thickness, ground plane dimensions, and Yagi–Uda element geometry on resonance behavior and directional performance. The results confirm that careful tuning of these design parameters leads to a consistent gain enhancement and stable radiation characteristics, establishing the proposed linear Yagi–Uda array as a strong candidate for next-generation sub-THz wideband communication systems.