On the basis of Generalized Snell’s Law of reflection, we propose to achieve frequency scanning radiation by decoupling spoof surface plasmon polaritons (SSPPs) from a corrugated metallic strip. Phase gradient metasurface (PGM) is utilized to modulate the dispersion behavior of the corrugated metallic strip. Since the phase gradient of the PGM is contrary to the wave vector of SSPPs, the dispersion curve of SSPPs can be translated into the fast-wave zone, leading to frequency scanning radiation. As an example, we demonstrate a frequency scanning antenna operating in 8.8-10.7GHz. A prototype was designed, fabricated and measured. The measured results show that the prototype can realize continuous beam scanning from 4.8° to 37.2°, with realized gain varying from 8dB to 13.1dB. Owing to surface confinement of SSPPs, the proposed method can be readily extended to the design of conformal frequency scanning antennas on curved faces.

In this paper, we propose a method of designing sharedaperture antennas based on excitations of both even-and odd-mode spoof surface plasmon polaritons (SSPPs). The antenna consists of a feeding monopole and a tapered SSPPs structure, both of which are placed vertically on a metallic ground. Due to tilted electric vectors of the monopole in near-fields, both even-and odd-mode SSPPs can be excited. Standing waves of even-mode SSPPs on the SSPPs structure will enable broadside or tilted radiation, while travelling waves of odd-mode SSPPs on the tapered end will enable end-fire radiation. Therefore, such an antenna configuration can achieve broadside, tilted and end-fire radiations. As an example, a shared-aperture antenna operating in C/X/Ku bands was designed, fabricated and measured. Both simulated and measured results verify that the antenna can achieve broadside radiation in 4.68-4.83GHz, tilted radiation in 8.51-8.82 GHz and end-fire radiation in 11.00-17.38 GHz, with peak gains about 2.7dB, 3.5dB and 6.8dB, respectively. The antenna itself can work in multiple bands with customized radiation patterns, without using several antenna radiators and complex feeding network. This work provides an effective method of designing shared-aperture antennas in future light-weight and multi-functional wireless communication systems.

High gain planar antennas always contribute large radar cross section (RCS) to low-observed platforms. To solve this contradiction, we propose a novel design of circularly polarized metasurface antenna characterized by low RCS but high gain. Split ring resonators play a twofold role as the array elements for linear polarization and as the unit cells of metasurface for RCS reduction. Four 2×2 arrayed SRRs are positioned with orthogonal orientations as a super-array element and fed with phase shift of 90° in between for left-handed circular polarization, respectively. On the other hand, based on its original arrangement, the open-circuited super-array element is also designed to be the super-cell of a (0°, 180°) reflective checkerboard metasurface. Owing to anti-phase energy cancelation and scattering, both the in-band and out-of-band RCS can be dramatically reduced. As indicated by the measurements in antenna, the fabricated prototype operating in X-band exhibits a combined bandwidth (3dB axial ratio, 3dB gain drop, and -10dB impedance matching) of 16% with a maximum realized gain of 17.9dB. Besides, under normal illumination, the measured specular reflection has been reduced by 10dB within 9.2-10.8GHz and by 7.5dB from 10.8 to 14GHz. This design method simultaneously ensures high gain antenna performance as well as meets the requirement for low-RCS.

Vortex beams with orbital angular momentum (OAM) can remarkably increase the channel capacity without signal process, thus attract more and more attention of researchers, and various novel methods of generating vortex beams blow out. In this work, a circular-polarized vortex beam reflector antenna was proposed via integrating vortex beam generated metasurface and beam focusing metasurface. The antenna consists of the metasurface reflector and a feed helical antenna. The phase distribution of the metasurface combines the OAM phase distribution and the beam focusing required phase distribution which is used to generate vortex beam from a point source. The measured results agree well with the simulated results, and both demonstrate that the reflector antenna can generate a vortex beam with OAM from 12 GHz to 18 GHz, and the realized gain is 22.4 dB at the center frequency 15 GHz.

We propose the design of in-plane feed antennas (IPFA) based on phase gradient metasurface (PGM). The in-plane feed is realized using PGM with large in-plane phase gradient, which can couple normally incident waves efficiently into surface waves along the surface. This is different from conventional reflector antennas and reflectarray antennas, where the focus lies above the reflector. As an example, an IPFA is demonstrated, which is composed of a superthin PGM and a waveguide feeding structure. Due to the large phase gradient of the PGM toward the feeding waveguide, incident waves can be coupled as surface waves into the waveguide; whereas transmitted waves can be radiated out along the normal of the PGM. Both the simulated and experimental results verify the high gain and high efficiency of the IPFA with in a broad band in 3.0-3.2 GHz.