A compact planar high-directional helical antenna for terahertz broadband applications

This paper demonstrates development of a small-scale planar helical antenna through design and performance studies for terahertz broadband usage. The conventional helical wire antenna concept is adopted for the design of the proposed planar helical antenna to obtain high directivity and bandwidth. The antenna maintains dimensions of 5.5 × 2 × 0.25 mm3 while using Rogers RT/duroid 5880 for the substrate coupled with copper conductors, which allows it to be used in contemporary communication and sensing platforms. Broadband impedance matching together with efficient radiation performance across 125 GHz to more than 750 GHz results from the optimized turn spacing and length variation. The proposed structure exhibits a peak gain ranging from 7.4 to 11.2 dBi while maintaining a high radiation efficiency between 82% and 94.3% across the operating band. Parametric studies investigate dimensional adjustments, material changes, substrate characteristics on resonance frequency shifts, gain variations, and efficiency levels. The results indicate that helical shape extensions and distance modifications result in better impedance matching; substrate height selection along with material type determines bandwidth potential and radiation output performance. The planar configuration ensures compact size and ease of integration with terahertz systems while providing stable radiation characteristics and high performance. Owing to these advantages, the proposed antenna is highly suitable for terahertz imaging, high-speed wireless communication, sensing, and radar applications.