Rongcao Yang

Optical Properties of a Y-Splitter Based on Hybrid Multilayer Plasmonic Waveguide

A Y-splitter based on hybrid multilayer plasmonic waveguide structure composed of silver–silica–silicon–silica–silver is introduced. Properties, such as the transmission rate and split ratio, are numerically investigated by changing the thickness of dielectric layers, bending radii of the bending parts, as well as input working wavelength. Results indicate that the proposed structure can have high transmission rates of >47% at the two output branches with split ratio close to 1:1. When the symmetry of the structure is broken by adjusting the bending radii of the bending parts, one may control the transmission rate of the two different output branches and then control the split ratio for a given working wavelength to a certain degree. Comparison reveals that the proposed Y-splitter is superior to the T-splitter within the wavelength range of 1000–1600 nm. These properties are helpful in the design and application of photonic devices and integration.

New types of exact quasi-soliton solutions in metamaterials

We consider a generalized nonlinear Schrodinger equation describing the propagation of ultrashort pulses in metamaterials (MMs) and present three new types of exact bright, dark, bright-grey quasi-solitons with a free constant associated with their amplitudes, pulse widths and formation conditions. Based on the Drude model, we analyze the existence regions and characteristics of these quasi-solitons in MMs. The results show that these bright and dark (grey) quasi-solitons can exist in wider regions of MMs and their intensities and pulse widths can be adjusted by choosing a suitable free constant. Furthermore, we take the third type of quasi-soliton solution as an example to numerically discuss the stabilities under slight perturbations of the frequency and the initial pulse width. The obtained results are helpful in exploring more solitary waves in MMs and providing a new reference for experimental verification.

Exact dipole solitary wave solution in metamaterials with higher-order dispersion

Abstract We present an exact dipole solitary wave solution in a mutual modulation form of bright and dark solitons for a higher-order nonlinear Schrödinger equation with third- and fourth-order dispersion in metamaterials (MMs) using an ansatz method. Based on the Drude model, the formation conditions, existence regions and propagation properties are discussed. The results reveal that the solitary wave may exist in a few parameter regions of MMs, different from those in optical fibres, and its propagation properties can be controlled by adjusting the frequency of incident waves in each existence region.

Polarization-Controlled and Flexible Single-/Penta-Band Metamaterial Absorber

In this paper, a polarization-controlled and flexible metamaterial absorber made of a set of wires etched on ultrathin teflon dielectric substrate is proposed. The simulation results showed that the proposed absorber achieved single-band absorptivity of 99.8% at 6.64 GHz for the TM (transverse magnetic) polarization wave and penta-band absorptivity of more than 99% at 11.68 GHz, 13.58 GHz, 15.48 GHz, 17.38 GHz, and 19.28 GHz for the TE (transverse electric) polarization waves. Moreover, each absorption peak had very narrow relative bandwidth and the position of penta-band absorption peaks could be adjusted by changing the length of the corresponding wire or selecting suitable substrate material according to actual requirements, because each wire can independently respond to electromagnetic (EM) waves. Furthermore, the surface current distributions corresponding to each absorption peak were studied to demonstrate the absorption mechanism. The absorption properties of the proposed structure with different bending radii and under different incident angles of the EM waves were investigated, showing good flexibility and incident angle-insensitive properties. In addition, the simulation results were confirmed by measuring a fabricated prototype. The proposed absorber may have useful applications in polarizers, sensors, bolometers, polarization detectors, etc.

A wideband dual-polarized patch antenna fed with the aperture-coupled microstrip

ABSTRACT In this paper, a compact broadband dual-polarized stacked patch antenna with the aperture coupled microstrip feed is proposed. By adding a parasitic disc patch, the bandwidth is effectively broadened. Meanwhile, to improve the isolation at the low frequency band, a rectangular slot is etched along the diagonal line of the ground plane. The measured results show that the proposed antenna can operate from 9.6 to 22.4 GHz and the relative bandwidth is 80%. Also, the isolation within the operating frequency band is better than 15 dB and the maximum gain reaches 4.08 dBi.

An omni-directional circularly polarized antenna with a low profile and wide axial-ratio beamwidth

ABSTRACT A novel low profile omni-directional circularly polarized (CP) antenna with wide axial-ratio (AR) beamwidth in the elevation plane is proposed. It is composed of a compound vortex radiator, a ground plane, and two groups of vias. By adjusting the structure of the compound vortex stub, |Eθ| = |Eφ| is realized in a wider range of θ. Also, the 90° phase difference between Eθ and Eφ is obtained by regulating the size of a sector patch at the end of the vortex stub. The measured results show that the proposed antenna has an impedance bandwidth of 3.2% (3.03–3.13 GHz) and a 3 dB AR bandwidth of 21.6% (2.5–3.17 GHz). Also, the 3 dB AR beamwidths at 3.10 GHz are 270° and 274° in the φ = 0° and φ = 90° planes, respectively. A good agreement between the simulated and measured results is obtained.