A unidirectional frequency beam‐scanning antenna using composite slow‐wave waveguide based on substrate integrated waveguide and spoof surface plasmon polariton structure.

In this study, a novel frequency beam‐scanning (FBS) antenna based on composite substrate integrated waveguide/spoof surface plasmon polariton (SIW/SSPP) waveguide is proposed. The composite SIW/SSPP slow‐wave waveguide is designed by embedding a series of periodic subwavelength H‐shaped grooves on the top surface of the SIW. Its transmission characteristics own both the features from SIW and SSPP, and can be flexibly mansplained by tuning the key structural parameters. To convert the propagating composite slow‐wave mode into the radiation mode effectively, a new flexible digital modulation method with staggered metallic vias is proposed and used. The presented beam‐scanning antenna has a simple feeding structure, a single dielectric layer, and a compact volume of 0.75 × 8.55 × 0.015 λ03. A prototype of the antenna is fabricated and tested to verify its performance. The experimental results demonstrate that the proposed antenna can realise a continuous beam‐scanning angle of 49° in an operating bandwidth of 8.7–9.2 GHz with a high frequency‐scanning sensitivity (FSS) of 9.8 °/100 MHz−1. Moreover, the measured results indicate that the antenna has high peak gain with an average level of 12.7 dBi, high radiation efficiency with an average level of 87%, and stable unidirectional radiation pattern in the working band. [ABSTRACT FROM AUTHOR]