Compact Dual-Band High-Efficiency Antennas Based on Spoof Surface Plasmon Polaritons

Abstract

A compact dual-band high-efficiency antenna based on spoof surface plasmon polaritons (SSPPs) is proposed by well exciting both the TM10 mode and the LC resonant mode. Each mode can be tuned separately without affecting the other mode. The whole SSPP slab is utilized as the radiator of the TM10 mode, while the air ring gap, the shorting pin, and a minor part of SSPP slab work as the radiator of the LC resonant mode. The compact size and the high radiation efficiency of the proposed antenna are due to the high field confinement and high effective refractive index of SSPPs. A reliable circuit model is first proposed for an SSPP antenna and applied to design it for dual-band operation. A prototype was fabricated using PCB technology and measured. The proposed antenna achieves a compact electrical size of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.18\lambda _{\mathbf {0}} \times 0.18\lambda _{\mathbf {0}} \times 0.07\lambda _{\mathbf {0}}$ </tex-math></inline-formula> , which is significantly smaller than its counterparts ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\lambda _{\mathbf {0}}$ </tex-math></inline-formula> is the wavelength at lower resonant frequency). Our proposed antenna possesses higher relative bandwidth per wavelength square area in comparison with other dual-band antennas. Both the simulated and measured results verified the high total efficiencies of the proposed dual-band antenna. The proposed antenna will have potential applications in wireless communication systems.