Graphene can be used as a platform for tunable absorbers its tunability of conductivity. In this paper, we proposed an "uneven dielectric slab structure" the terahertz (THz) absorber based on graphene. The consists graphene-dielectric stacks and electric conductor layer, which is easy to fabricate in manufacturing technique. Fine tuning absorption resonances conveniently achieved by adjusting bias voltage. Both narrowband broadband made structure are demonstrated without using patterned...

A novel scheme is proposed for analog multipath interference cancellation based on two polarization modulators (PolMs) and a dispersive element. Multiple optical compensation branches are formed by an array of tunable lasers. By adjusting the wavelength power each laser, delay magnitude known signal can be finely tuned, so that accurately reconstructed counter-phase cancellation. The dispersion-induced RF fading in link also compensated because PolM-based intensity modulation scheme, best...

A design of absorber using two-dimensional (2-D) periodic arrays double-square split loops and resistive strips printed on grounded dielectric substrate is investigated in this letter. Unlike the traditional structure, graphene sheets are proposed for thin absorbing structures at microwave frequencies. The analysis absorption properties based dynamic model graphene, which takes into account surface impedance layer. Both narrowband broadband tunable absorbers can be demonstrated with same...

This paper presents a multilevel fast adaptive cross-approximation (MLFACA) algorithm for accelerated iterative solution of the method moments (MoM) matrix equation electrically large targets. The MLFACA compresses impedance submatrices between well-separated blocks into products sparse matrices, constructed with aid cross-sampling (FACS) scheme and butterfly algorithm. As result, can reduce both computational time storage MoM to <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML"...

We demonstrate that periodically textured closed surface with multiple groove depths can support multi-band spoof localized plasmons (LSPs). It is interesting to note the LSPs in each band resemble those generated by of same periodicity corresponding single depth. In this way, it paves way for generation and design LSPs. Moreover, resonance structures devices, such as resonator, oscillator, other band-notched microwave terahertz regimes be realized.

The characteristic basis function method has been proposed to accelerate the direct solution of moments by reducing number unknowns. However, with increase in target size, reduced matrix will still become too large directly solve and store. In this communication, algorithm based on Sherman-Morrison-Woodbury (SMW) formula is employed address problem for first time. It compresses into a product block diagonal matrices aid SMW adaptive cross approximation. Subsequently, inverse can be easily...

In this work, we build a smooth bridge between coaxial waveguide and plasmonic with subwavelength periodically cylindrical radial grooves, to realize high-efficiency mode conversion conventional guided waves spoof surface plasmon polaritons in broadband. This consists of flaring connected metal wire corrugated gradient grooves. Experimental results the transmission reflection coefficients show excellent agreement numerical simulations. The proposed scheme can be extended readily other bands...

Localized spoof plasmons arising with textured closed surfaces have been theoretically studied and experimentally verified, which resemble the localized surface (LSPs) in optical regime. In this work, we go one step further demonstrate that part of resonance modes cavities pertain to (spoof-LSPs) modes. We show existence LSPs periodically perfect electric conductor circular make an analogy between these real metallic Drude model Also, a metamaterial approach is presented capture resonant features

A new fast dipole method (FDM) is proposed for the electromagnetic scattering from arbitrarily shaped three-dimensional (3D), electrically large, perfect electric conducting (PEC) targets in free space based on concept of equivalent dipole-moment (EDM) and multipole (FMM). The electric-field, magnetic-field combined-field integral equations (CFIE) this algorithm have been developed implemented. Although basic acceleration idea FDM has borrowed FMM, specific implementation these two...

A fast adaptive cross-sampling (FACS) scheme for the sparsified cross approximation (SPACA) algorithm is proposed to improve conventional uniform spatial sampling. The FACS adaptively samples each well-separated block pair in an iterative manner reach a given sampling error. At iteration, first selects set of initial with distribution block, and then uses (ACA) find important from samples. Compared sampling, easier control error needs fewer same By reducing number samples, can enhance...

A general circuit model is presented to study the absorption of electromagnetic waves by a graphene-based structure at low-terahertz frequencies. The absorber consists monolayer graphene which printed on uneven dielectric slabs, with metallic ground plane placed bottom interface. approach based simple and accurate analytical models for metal strips or patches. Compared full-wave simulator software, proposed method shows high efficiency results obtained from suggested agree well those...

A new hybrid adaptive cross approximation‐characteristic basis function method (ACA‐CBFM) is proposed to efficiently solve the electromagnetic scattering problems. In conventional ACA‐CBFM, ACA only applied speed up construction of reduced matrix that directly solved and stored. However, with increase size targets under analysis, will become so large it difficult store. this study, further compressed by approximation‐singular value decomposition (ACA‐SVD) an iterative method, which leads...

In this work, we explore the existence of multiband localized spoof plasmons (LSPs) in closed textured cavities with multiple groove depths. It is interesting to note that LSPs each band resemble those generated by 2D same periodicity corresponding single depth, and field distributions confinement characteristics plasmon-like modes such a corrugated cavity are different from conventional cavity. Hence, these resonance structures can find potential applications microwave terahertz frequencies.

Abstract In this article, an improved fast dipole method (IFDM) is proposed to enhance the accuracy of conventional (FDM). Through expanding terms R α and RR in formulation equivalent dipole-moment (EDM) using a simple Taylor's series, FDM can represent interaction between two dipoles as aggregation-translation-disaggregation form more accurately than FDM. Furthermore, complexity matrix-vector products (MVPs) far-group pair, such block i j, also be reduced from O(N N j ) O(Ni + Nj ), where...

The adaptive cross approximation (ACA) enhanced multilevel characteristic basis function method (MLCBFM) is studied in this article. It well known that the impedance submatrices containing reaction terms of low‐level functions such as Rao–Wilton–Glisson have low‐rank property. However, authors find high‐level matrices between nonoverlapping blocks are also low rank and can be compressed efficiently. This property used to efficiently calculate reduced matrix MLCBFM through ACA algorithm...

Abstract In this article, the fast dipole method (FDM) is combined with adaptive modified characteristic basis function (AMCBFM) to solve electromagnetic scattering from perfect electric conducting (PEC) targets. The AMCBFM an efficient for analyzing problems via size reduction of original matrix in moments (MoM) equation. However, AMCBFM, functions (CBFs) generations process and reduced calculation are still very time-consuming containing many matrix-vector products (MVPs)...

In this paper, a new time domain fast dipole method (TD-FDM) is proposed for solving time-domain magnetic field integral equations.The scheme the extension of frequency (FDM) to domain.The principle based on Taylor series expansion far fields.The computational complexity TD-FDM scales as O(N 3/2 s N t ) opposed 2 marching-on in-time (MOT) method.Here, number spatial basis functions and steps.Numerical results about electromagnetic scattering from perfect electric conductor (PEC) objects are...

In this paper, a novel parametric modeling approach of electromagnetic (EM) behaviors an unequally spaced linear array based on artificial neural network (ANN) is proposed. The ANN model takes the locations elements as input, with training and testing sample set obtained by full-wave EM simulations. After training, can achieve active element patterns (AEPs) rapidly once are input. Thus, radiation pattern including mutual coupling platform effects be superposition AEPs. validity efficiency...

In this study, a multilevel fast dipole method (MLFDM) is proposed for the electromagnetic scattering from arbitrarily shaped three-dimensional (3D) perfect electric conducting targets to improve equivalent dipole-moment (EDM). The EDM views basis functions as dipoles models and gives very extremely simplified forms impedance element. However, it incapable of saving memory matrix–vector multiplication (MVM) time. MLFDM, grouping scheme employed, simple Taylor&apos;s series expansion distance...

Abstract A simple and compact dual‐band H‐shaped slot antenna for wireless local area network applications is proposed.The proposed composed of an on the ground plane with size 23 mm by 32 mm. The substrate material foam. fed microstrip at its top. impedance bandwidth, radiation pattern, gain were simulated. results show that just covers WLAN bands (2.4–2.485, 5.15–5.35, 5.725–5.825 GHz), remaining steady. measurement bandwidth was carried out a analyzer. good agreement between simulation...

In this paper, methods of conformal antenna RCS reduction are researched, similar with planar antenna. Design two microstrip antenna, resonant at the same frequency, former is an ordinary The other uses impedance loaded as well ground plane and patch slotted technique. results demonstrate that in 2 – 8GHz, latter achieve a good reduction, up to 20dB. At time, gain loss only 0.2dB.

This article presents a fast solution to the volume–surface integral equation for electromagnetic scattering from three-dimensional (3D) targets comprising both conductors and dielectric materials by using multilevel dipole method (MLFDM). scheme is based on concept of equivalent dipole-moment (EDM) that views Rao–Wilton–Glisson Schaubert–Wilton–Glisson basis functions as models with moments. In MLFDM, simple Taylor's series expansion terms Rα (α = 1, −1, −2, −3) R̂R̂ in formulation EDM...

In this paper, a concentric circular-patch/ring-combination reflectarray element is proposed. To obtain phase curve with low slope in an adequate range, its size optimized by parametric simulation HFSS. Then, the electromagnetic behavior of proposed compared that circular patch and circular-patch/ring/ring-combination element. Utilizing element, 13×13 elements radiating at direction 30° designed frequency 10GHz. Simulated results show peak gain 22.7dB half-power beamwidth E-plane 9.8°.