Transmission-Type 2-Bit Programmable Metasurface for Single-Sensor and Single-Frequency Microwave Imaging.

The programmable and digital metamaterials or metasurfaces presented recently have huge potentials in designing real-time-controlled electromagnetic devices. Here, we propose the first transmission-type 2-bit programmable coding metasurface for single-sensor and single- frequency imaging in the microwave frequency. Compared with the existing single-sensor imagers composed of active spatial modulators with their units controlled independently, we introduce randomly programmable metasurface to transform the masks of modulators, in which their rows and columns are controlled simultaneously so that the complexity and cost of the imaging system can be reduced drastically.

Transmitting information of an object behind the obstacle to infinity.

We propose an illusion device that transforms a metallic cylinder into a Luneburg lens by using transformation optics. Such a transformed focusing lens guides electromagnetic waves to propagate around the central metallic cylinder smoothly and be focused on one spot, and thus the information of an object behind the obstacle can be transmitted to infinity. In order to realize the required-anisotropic parameters with high permittivity and low permeability, we design embedded split-ring resonators (SRRs) to increase the permittivity of the traditional SRR structures.

Annular focusing lens based on transformation optics.

We propose and design a kind of annular focusing lens based on transformation optics. Based on the method of eigen-mode expansions, closed-form expressions are derived to analyze the proposed annular lens rigorously. We show that the annular lens has excellent focusing property.

Design and rigorous analysis of transformation-optics scaling devices.

Scaling devices that can shrink or enlarge an object are designed using transformation optics. The electromagnetic scattering properties of such scaling devices with anisotropic parameters are rigorously analyzed using the eigenmode expansion method. If the radius of the virtual object is smaller than that of the real object, it is a shrinking device with positive material parameters; if the radius of the virtual object is larger than the real one, it is an enlarging device with positive or negative material parameters.