In this work, a broadband and broad-angle polarization-independent random coding metasurface structure is proposed for radar cross section (RCS) reduction. An efficient genetic algorithm is utilized to obtain the optimal layout of the unit cells of the metasurface to get a uniform backscattering under normal incidence. Excellent agreement between the simulation and experimental results show that the proposed metasurface structure can significantly reduce the radar cross section more than 10 dB from 17 GHz to 42 GHz when the angle of incident waves varies from 10° to 50°. The proposed coding metasurface provides an efficient scheme to reduce the scattering of the electromagnetic waves.

We provide further theoretical insights and experimental verification of the modal-dispersion-induced effective surface-plasmon polaritons (ESPPs) by engineering the transverse-electric (TE) modes in conventional rectangular waveguides. The complete field distributions, dispersion relations, and asymptotic frequency of the ESPPs are derived analytically. Wave-port excitations and smooth bridges are designed for the mode conversion between propagating modes in rectangular waveguides and the ESPPs. Analytical calculations and numerical simulations are performed for TE 10 -and TE 20 -mode-induced ESPPs, showing excellent agreement. Moreover, we design a double-layered substrate-integrated waveguide showing that ESPPs are supported at the interface between the two layers with different dielectric constants. This work opens up an avenue for low-frequency designer surface plasmons and may find potential applications in the design of compact filters, resonators, and sensors of ESPPs in the microwave and terahertz frequencies.

In this work, we demonstrate that composite spoof surface plasmon polaritons can be excited by coplanar waveguide, which are composed of two different spoof surface plasmon polaritons (SSPPs) modes propagating along a periodically corrugated metallic thin film simultaneously. These two SSPPs correspond to the dominant modes of one-dimensional (1D) periodical hole and groove arrays separately. We have designed and simulated a planar composite plasmonic waveguide in the microwave frequencies, and the simulation results show that the composite plasmonic waveguide can achieve multi-channel signal transmission with good propagation performance. The proposed planar composite plasmonic metamaterial can find potential applications in developing surface wave devices in integrated plasmonic circuits and multi-channel signal transmission systems in the microwave and terahertz frequencies.