Baokun Xi

In this paper, an ultrathin linearly polarized transmission line (TL) based on tilted microstrip spoof surface plasmon polaritons (SSPPs) is proposed. The proposed structure of the TL consists of an ultrathin corrugated metallic strip with periodic tilted groove arrays and metallic ground. Compared with the reported traditional SSPPs, the proposed SSPPs structures with tilted grooves can support the SSPPs wave with a larger propagation constant, which means a stronger field confinement in the microstrip SSPPs structure and effectively lower the dimension in transverse direction of the TL. Besides, the simulation demonstrates that the wave confinement performance can be well maintained when the grooves tilt from 0 to 60°, and the electric field vectors of the tilted grooves undergo a rotation correspondingly, resulting in a flexible polarization. Therefore, the polarization of different angles can be easily realized when the proposed SSPPs is employed as radiating or feeding structure. To verify characteristic of the proposed structure at microwave frequencies, we simulate, fabricate and measure a back‐to‐back transition sample with 45°‐titled grooves. Both simulations and measured results have clearly validated the good characteristic of the proposed designs.

A new low‐profile, dual‐polarized reflect‐transmit‐array antenna which combines the linearly polarized reflectarray (RA) and circularly polarized transmitarray (TA) with a shared aperture is proposed. The antenna adopts a three‐parallel dipole and a two‐surface dipole connected by vias as radiating elements in RA and TA design, respectively. By using the polarized grid, TA is decoupled from RA, which greatly enhanced the efficiency and significantly simplified the whole design process. To minimize the overall thickness, the TA employs double metal layer with two vias instead of multilayer structures. The operating mechanism of the TA layer is then analyzed by characteristic mode analysis. An array prototype with a 256‐mm circular aperture was fabricated and experimentally verified. The measured gains in reflect mode and transmit mode is 27.5 dB with 54.3% aperture efficiency and 26.7 dB with 45.1% aperture efficiency, respectively. This prototype confirms the feasibility of designing a low‐profile, multifunctional, wideband, and high‐efficiency reflect‐transmit array.

This article develops an efficient solution to design beam‐scanning transmitarray (TA). The four‐layer unit associated with the focal planar substrate integrated waveguide (SIW) array is presented and characterized. The proposed linearly polarized TA is implemented as four‐layer sheet admittance composed of the subwavelength unit, whose transmission feature would be accurate analyzed by the equivalent circuit model. The phase layout of TA is optimized by using the PMM method in order to achieve a wide scanning behavior and reduce the scan loss. Arc‐shaped SIW horn antenna array is adopted as the feeding source. Artificial impedance surfaces printed on either side against the low‐profile substrate results in a greatly enhanced radiation performance. The TA and feeds presented at 20 GHz are both fabricated using standard PCB processing. The measured results show a greatly improved ±45° scan range with the gain loss of 0.73 dBi by switching the SIW horn antenna. Good radiation and bandwidth characters are performed in all states of operation for both ports, confirmed the effectiveness of proposed design process.