Borui Bian

Comment on “Photonic bands in two-dimensional microplasma array. I. Theoretical derivation of band structures of electromagnetic waves” [J. Appl. Phys.101, 073304 (2007)]

Recently, theoretical derivation of band structures of electromagnetic waves in two-dimensional microplasma array has been induced by Osamu Sakai et al. [J. Appl. Phys. 101, 073304 (2007)] using a modified plane wave expansion (PWE) method and a frequency-dependent finite difference time–domain (FDTD) method. This report reveals band diagrams with the effects of plasma electron collision frequency, especially focuses on the TE wave by nonmagnetized plasma. Although the band diagrams of TE wave and formulas of calculation look correct at first glance, there are some mistakes in the report which are unfortunately ignored by the authors. The correct formulas of the modified PWE method and FDTD method will be proposed.

Novel triple-band polarization-insensitive wide-angle ultra-thin microwave metamaterial absorber

We report the design, analysis, fabrication, and measurement of a novel microwave triple-band metamaterial absorber that obtains three distinct high absorption peaks. The absorber is constructed of a periodic array of new resonant structure printed on a dielectric material with the thickness of λ/67 at the lowest fundamental resonant frequency. By manipulating the periodic patterned structures, significantly high absorption can be obtained at three specific resonance frequencies. This kind of triple-band absorber is polarization insensitive, and the absorption peaks remain high with large angles of incidence for both transverse electric and transverse magnetic polarizations, which provide more efficient absorptions for non-polarized or oblique incident electromagnetic wave. The experimental results show excellent absorption rates and the characteristic of polarization-insensitive for a wide range of incidence angles in the desired frequencies, which are in good correspondence with the simulated results.

A novel ultrathin and broadband microwave metamaterial absorber

In this paper, the design, simulation, fabrication, and measurement of an ultrathin and broadband microwave metamaterial absorber (MMA) based on a double-layer structure are presented. Compared with the prior work, our structure is simple and polarization insensitive. The broadband MMA presents good absorption above 90% between 8.85  GHz and 14.17 GHz, with a full width at half maximum (FWHM) absorption bandwidth of 6.77 GHz and a relative FWHM absorption bandwidth of 57.3%. Moreover, the structure has a thickness of 1.60 mm (only λ/20 at the lowest frequencies). The experimental results show excellent absorption rates which are in good correspondence with the simulated results. The broadband absorber is promising candidates as absorbing elements in scientific and technical applications because of its broadband absorption and polarization insensitive.

Properties of Omnidirectional Photonic Band Gaps in Fibonacci Quasi-Periodic One-Dimensional Superconductor Photonic Crystals

In this paper, the properties of the omnidirectional photonic band gap (OBG) realized by one-dimensional (1D) Fibonacci quasi-periodic structure which is composed of superconductor and isotropic dielectric have been theoretically investigated by the transfer matrix method (TMM). From the numerical results, it has been shown that this OBG is insensitive to the incident angle and the polarization of electromagnetic wave (EM wave), and the frequency range and central frequency of OBG cease to change with increasing Fibonacci order, but vary with the ambient temperature of system, the thickness of the superconductor, and dielectric layer, respectively. The bandwidth of OBG can be notably enlarged with increasing the superconductor thickness. Moreover, the frequency range of OBG can be narrowed with increasing the thickness of dielectric layer and ambient temperature. The damping coe-cient of superconductor layers has no efiect on the frequency range of OBG under low- temperature conditions. It is shown that Fibonacci quasi-periodic 1D superconductor dielectric photonic crystals (SDPCs) have a superior feature in the enhancement frequency range of OBG. This kind of OBG has potential applications in fllters, microcavities, and flbers, etc.

Tunable photonic bandgap in a one-dimensional superconducting-dielectric superlattice

The transmittance of one-dimensional photonic crystals consisting of superconductor and lossless dielectric has been systematically studied through the transfer-matrix method. Obviously, the shift of the photonic bandgap (PBG) becomes more noticeable by adjusting the thicknesses of the dielectric layers than that of superconductor layers. Furthermore, the number of PBGs can be controlled by varying the thicknesses of dielectric layers. Compared to the thicknesses of the dielectric layers, the width of the PBGs is more sensitive to the thicknesses of the superconductor layers. However, the width of the first PBG promptly varies when the thicknesses of the dielectric layers increase from 0 to 40 nm. If the contribution of the normal conducting electrons of the superconductor is nonnegligible, the temperature of the superconductor has no influence on the width of the PBGs. Moreover, the damp coefficient does not affect the PBGs under low-temperature conditions.

Multi-band polarization-insensitive metamaterial absorber based on Chinese ancient coin-shaped structures

In this paper, the design, simulation, fabrication, and measurement of the five-band metamaterial absorber (MMA) based on Chinese ancient coin-shaped structure are proposed. Simulation results show that the proposed absorber has five distinctive absorption peaks at frequencies of 2.538 GHz, 7.092 GHz, 9.702 GHz, 13.302 GHz, and 15.588 GHz with the absorptivity of 0.99, 0.99, 0.99, 0.98, and 0.99, respectively. Experiment results matches well with the simulation. Both simulation and experiment results exhibit that the MMA sample is polarization insensitive for transverse electric and transverse magnetic incident wave. It also shows that high absorption for wide angle of incidence is up to 60°. Finally, the current distribution for the MMA is presented to gain an insight into the physics behind the multiple absorption mechanism. The five-band absorber is promising candidates as absorbing elements in scientific and technical applications because of its multiband absorption, polarization insensitive, and wide...

Omnidirectional photonic band gap enlarged by one-dimensional ternary unmagnetized plasma photonic crystals based on a new Fibonacci quasiperiodic structure

In this paper, an omnidirectional photonic band gap realized by one-dimensional ternary unmagnetized plasma photonic crystals based on a new Fibonacci quasiperiodic structure, which is composed of homogeneous unmagnetized plasma and two kinds of isotropic dielectric, is theoretically studied by the transfer matrix method. It has been shown that such an omnidirectional photonic band gap originates from Bragg gap in contrast to zero-n¯ gap or single negative (negative permittivity or negative permeability) gap, and it is insensitive to the incidence angle and the polarization of electromagnetic wave. From the numerical results, the frequency range and central frequency of omnidirectional photonic band gap can be tuned by the thickness and density of the plasma but cease to change with increasing Fibonacci order. The bandwidth of omnidirectional photonic band gap can be notably enlarged. Moreover, the plasma collision frequency has no effect on the bandwidth of omnidirectional photonic band gap. It is shown ...

Electromagnetically induced transparency with large delay-bandwidth product induced by magnetic resonance near field coupling to electric resonance

In this paper, we numerically and experimentally demonstrate electromagnetically induced transparency (EIT)-like spectral response with magnetic resonance near field coupling to electric resonance. Six split-ring resonators and a cut wire are chosen as the bright and dark resonator, respectively. An EIT-like transmission peak located between two dips can be observed with incident magnetic field excitation. A large delay bandwidth product (0.39) is obtained, which has potential application in quantum optics and communications. The experimental results are in good agreement with simulated results.

Novel three-band microwave metamaterial absorber

In this paper, a novel three-band microwave metamaterial absorber is presented. The proposed absorber consists of a metallic planar cross and square layer on the top and a metallic ground plane at the bottom. They are separated by a dielectric layer. The experimental results show that the proposed absorber exhibits triple band absorption responses lying in C-band, X-band, and Ku-band. The proposed absorber can perform absorption peaks at three resonant frequencies of 6.16, 8.76, and 12.54 GHz with the absorption of 99.87, 99.98, and 99.99% can be acquired, respectively. In addition, the absorber can operate at large incident angles for both TE and TM polarization.

The properties of photonic band gaps for three-dimensional plasma photonic crystals in a diamond structure

In this paper, the properties of photonic band gaps (PBGs) for two types of three-dimensional plasma photonic crystals (PPCs) composed of isotropic dielectric and unmagnetized plasma with diamond lattices are theoretically investigated for electromagnetic waves based on a modified plane wave expansion method. The equations for type-1 structure are theoretically deduced, which depend on the diamond lattices realization (dielectric spheres immersed in plasma background). The influences of dielectric constant of dielectric, plasma collision frequency, filling factor, and plasma frequency on PBGs are investigated, respectively, and some corresponding physical explanations and the possible methods to realize the three-dimensional PPCs in experiments are also given. From the numerical results, it has been shown that not only the locations but also the gap/midgap ratios of the PBGs for two types of PPCs can be tuned by plasma frequency, filling factor, and the relative dielectric constant, respectively. However, the plasma collision frequency has no effect on the frequency ranges and gap/midgap ratios of the PBGs for two types of PPCs.