A Symmetric Tri-Port Phase Mode Antenna Based on Radial SSPPs’ Scatterer and Its Linear Arrays

A symmetric tri-port phase mode antenna (PMA) based on radial spoof surface plasmonic polaritons’ (SSPPs’) structure and two kinds of 1-D linear arrays of it are proposed with extended 2-D scanning characteristics. The proposed tri-port PMA is composed of a horizontal metal ground, a parallel circular PCB (<inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$0.28\lambda \times 0.28\lambda $ </tex-math></inline-formula>), and feeding pillars connecting them. The radial spoof surface plasmonic polaritons’ (SSPPs’) scatterer and three feeding spiral arms excited by three isolated ports are printed on each side of the PCB. The three ports generate similar hybrid EM modes with only angular differences, which can be separated into fields equivalent to those excited by a horizontal and vertical current element by the SSPPs’ scatterer. The superposition of fields with two controllable independent phased differences contributes to 2-D scanning patterns of the PMA, which further facilitates wide-range 2-D scanning characteristics of two kinds of 1-D arrays applying the generalized principle of pattern multiplication (GPPM). Beam scanning ranges <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$- 92^{\circ }~\le \theta _{\mathrm {m}}~\le 92^{\circ }$ </tex-math></inline-formula> and <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$92^{\circ } \le \theta _{\mathrm {m}} \le 91^{\circ }$ </tex-math></inline-formula> are realized by two <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$1\times 4$ </tex-math></inline-formula> linear arrays with a peak gain of 11.5 dBi and a gain fluctuation of 4.9 and 4.7 dB. The extra independent channels and scanning properties of the presented PMA and its arrays can be further exploited for more promising applications such as communication, direction finding, and navigation systems.