A Planar Quad-Port Phase Mode Antenna Based on Radial SSPPs Radiator and Its Arrays

A planar quad-port phase mode antenna (PMA) based on radial spoof surface plasmon polaritons (SSPPs) radiator and two arrays of it are proposed with extended 3-D scanning and polarization controlling characteristics. The proposed quad-port PMA is composed of a tri-layer PCB with a grounded SSPPs radiator, four feed patches, and the ground. The four isolated ports generate similar hybrid EM modes with structural angular differences and phase differences applied on the ports. The superposition of fields with three controllable independent phased differences contributes to a scanning range of <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$-66^{\circ }\le \theta _{\text {me}}\le 66^{\circ }$ </tex-math></inline-formula> in both <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">xoz</i> plane and <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">yoz</i> plane, and controllable polarization variation with polarization ratio shifting from 0.6 to 21.3 dB in the main lobe width, which further facilitate wide-range 2-D scanning and polarization controlling characteristics of arrays through generalized principle of pattern multiplication (GPPM). Scanning range <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$-71^{\circ }\le \theta _{\text {m}} \le 71^{\circ }$ </tex-math></inline-formula> in <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">xoz</i> plane with extremely low gain fluctuation 2.4 dB within <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$-60^{\circ }\le \theta _{\text {m}} \le 60^{\circ }$ </tex-math></inline-formula> and aperture efficiency 98% at <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\theta _{\text {m}}=0^{\circ }$ </tex-math></inline-formula> and scanning range <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$-65^{\circ }\le \theta _{\text {m}} \le 65^{\circ }$ </tex-math></inline-formula> in <italic xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">yoz</i> plane are realized by the <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 array. Scanning range <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$-65^{\circ }\le \theta _{\text {m}} \le 65^{\circ }$ </tex-math></inline-formula> is realized by the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$2\times 2$ </tex-math></inline-formula> array with aperture efficiency 98% at <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$\theta _{\text {m}}=0^{\circ }$ </tex-math></inline-formula>. The wide-range scanning properties of the presented arrays can be further exploited in large-scale 2-D arrays for more promising applications.