Mohammad Abrishamian

Khaje Nasir Toosi University of Technology | KNTU · Faculty of Electrical and Computer Engineering

A slot array substrate integrated waveguide antenna is proposed by utilizing novel center inclined slots with non-uniform spaces for imparting feeding advantages of standing and traveling waves. This 1 × 8 array antenna introduces a 13.2 dB gain at center frequency of 59.9 GHz with −10 dB return loss from 58.9 GHz to 60.9 GHz (roughly 2 GHz) and cr...

Here, we benefit from the strong nonlinear response of graphene and the rich variety of resonances provided by a graphene/dielectric Fibonacci multilayer to realize bistability and multistability in the terahertz (THz) frequency range. Toward this pursuit, we employ the nonlinear transfer matrix method. We examine the suitability of resonances in t...

We report on the plasmonic resonance enhanced terahertz (THz) second harmonic generation (SHG) from graphene via the technique of attenuated total reflection (ATR) in the Otto configuration. Through our finite-difference timedomain (FDTD) numerical simulations, we reveal how greatly different parameters including the radiation incidence angle, the...

The transmission spectra of microribbon graphene arrays are investigated with a circuit model based on the transmission line method. The Accuracy of the proposed method is comparable with full-wave electromagnetic simulation results versus chemical potential, incident angle, dimensions of microribbons, and the permittivity of the substrate. This ri...

Here we develop and extend a transmission line method (TLM) to analyze the performance of graphene assisted metamaterial (GM) devices working in the terahertz (THz) band. We demonstrate that a circuit model can be presented for different parts of the device including graphene and also the patterned metallic sheet by analyzing the distribution of su...

By exploiting the interesting trait of graphene to have electrically tunable first- and third-order conductivities besides its capability to support plasmonic resonances at terahertz frequencies, here, through the nonlinear finite-difference time-domain numerical technique we developed, we demonstrate a noticeable improvement in the conversion effi...

In this study, we demonstrate how field enhancement due to plasmonic resonances can noticeably improve the efficiency of third harmonic generation (THG) from graphene sheets on a grating substrate under normal illumination of terahertz (THz) waves. We explore how different parameters of graphene and the substrate can affect the strength of the reso...

In this paper, a novel compact horn antenna (aperture width=144mm) is proposed. By the novelty in design frequency and time characteristics of antenna are improved. The achieved Half Power Beam Width (HPBW) of the presented antenna is and polarization is relatively circular at 2.45 GHz. Voltage Standing Wave Ratio (VSWR) is about 1.4. Also Side and...

We study the propagation characteristics of surface Plasmon polaritons (SPPs) on a patterned graphene sheet incorporating a subwavelength ribbon resonator and a Kerr nonlinear bounding medium (substrate or top cladding) which provides tunable bandpass filtering in the THz regime. We study theoretically and via modeling the tunability of maxima in t...

We propose and numerically investigate an efficient method for long-range third-harmonic generation (THG) of propagating surface plasmon polaritons (SPP) waves on graphene sheets for nonlinear plasmonic purposes in the terahertz (THZ) gap region of the electromagnetic spectrum via a developed nonlinear finite-difference time-domain technique. We re...

This research investigated imaging quality of two important methods widely used in electromagnetic inverse scattering problems. The algorithms, time reversal (TR) and linear sampling method (LSM), were compared for resolution of point imaging and a correlation indicator to determine image quality. Comparisons were made in single- and multifrequency...

Here, we take the advantage of the strong electromagnetic field of surface plasmon polaritons (SPPs) on graphene to design a tunable terahertz plasmonic Bragg reflector by the intensity of propagating SPP wave. A periodic variation in the effective mode index of SPPs in the direction of their propagation on a graphene layer, required for Bragg scat...

Resonance frequency is examined for its effect on the linear sampling method (LSM). The aim of the study is to present an evaluation of occurrence of anomaly at some special frequencies in the LSM procedure. A comprehensive survey is done to analyze the destructive effect of resonance for LSM analysis. Analytical resonance calculations are used to...

An improved 2×2 microstrip patch antenna (MPA) array is proposed for impedance bandwidth enhancement, low back-lobe radiation, high co-to-cross polarization levels, and compact size at 60 GHz. Utilizing a novel center-fed coaxial-to-substrate integrated waveguide (SIW) transition and a comb-shape choke structure, the antenna's electrical performanc...

An improved 2×2 microstrip patch antenna (MPA) array is proposed for impedance bandwidth enhancement, low back-lobe radiation, high co-to-cross polarization levels, and compact size at 60 GHz. Utilizing a novel center-fed coaxial-to-substrate integrated waveguide (SIW) transition and a comb-shape choke structure, the antenna's electrical performanc...

Nanoantenna arrays can offer unique possibilities for large local-field enhancement, high directivity, and also wavelength tunability over a wide spectral range. In this paper, a semi-log-periodic array of nanospheroidal elements has been studied, which exhibits a narrower beam and also a higher electric field enhancement in comparison with an equa...

The major deficiency of conventional 'balanced antipodal Vivaldi antenna' (BAVA) is its tilted beam over upper working frequencies. This study reports on a new BAVA to overcome this defect. By applying a dielectric lens in front of the antenna's aperture, beam-tilting in E-plane was improved within the ultra-wideband frequency range, as well as hig...

We discuss here the realization of electrically tunable beam focusing and splitting using a single graphene flake with operation in the terahertz regime. The required conductivity pattern along a strip on the background graphene layer for focusing and splitting phenomena is created by the proper design of an uneven ground plane. The strip is illumi...

A graphene-based graded index (GRIN) planar lens with the capability of being tuned by the external magnetostatic bias field is proposed and numerically investigated. Based on the effective mode index of propagating transverse magnetic (TM) surface plasmon polaritons (SPP) on the graphene sheet, a design procedure to achieve a beam-focusing phenome...

The realization of electrically tunable beam focusing using a properly designed conductivity pattern along a strip on a background single graphene flake with operation in the terahertz regime is proposed and numerically investigated. The strip is illuminated with a guided surface plasmon polaritons (SPP) plane wave and the physical origin of the de...

We report a numerical study on the optical tuning of a notch filter comprised of an array of engineered graphene microribbons. The notch on the normal incidence transmission spectra is created due to light–plasmon coupling in graphene. Besides investigating the effect of structural parameters and electrostatic gating on the graphene plasmon excitat...

In the recent years, the strong demand for high performance, low cost and high gain antennas for telecommunication, surveillance, and imaging applications has rapidly grown at microwave and higher frequencies. High speed wireless links require modular, compact size and high directivity with low cross polarization antennas. To demonstrate the propos...

The proposed high performance, high gain, low cost antenna for telecommunication, networking, surveillance, etc. has been presented in this paper. Nevertheless, high speed wireless links need compact structure antennas with high directivity and low attenuation level. Therefore, there is a way to demonstrate these mentioned concepts by employing bow...

A new nanoplasmonic notch filter and a biosensor, based on the loop–stub configuration, are proposed and studied. Our finite-difference time-domain simulations reveal that the resonant mode of the proposed structure can be easily controlled by varying the width of the horizontal branch of the loop–stub structure. The proposed plasmonic biosensor ha...

We report the observation of focusing and deflection phenomena by employing a novel technique to perform phase front profile design in nanoslit-based planar plasmonic lenses and beam deflectors. Introducing perpendicular cuts and bumps to the perforated nanoslits on a thin metallic film is utilized to change the effective depth of the nanoslits whi...

In this numerical study, a Gaussian beam-to-slab waveguide coupler for both modes of TM and TE has been studied. For this purpose, a concrete structure is suggested, in which the graded index photonic crystal lens and the slab waveguide are in the same structure composed of Si material, and can be fabricated with a single-step lithography process....

A highly tunable optical nanoantenna element is proposed through gradual transformation from a sphere to a prolate spheroid. This new element induces field enhancement and an increase in resonance frequency. Rather than a purely metallic material, we propose the use of a metal-coated dielectric spheroid as a nanoelement because of its flexibility....

A tunable multi-channel plasmonic filter based on the metal-insulator-metal (MIM) structure of rectangular cavities is proposed and numerically investigated by the two-dimensional finite difference time domain (2D FDTD) method. Proper positioning of the output waveguides according to the distribution of the inside fields of the cavity makes it poss...

In this paper, illusion optics theory is employed to form Bragg gratings in an optical waveguide in order to design an optical switch. By using an illusion device at a certain distance from the waveguide, the effective refractive index of the waveguide is remotely modulated, turning the waveguide into a distributed Bragg reflector (DBR) which block...

We proposed a simple asymmetric rectangular band-stop filter based on metal-insulator-metal plasmonic waveguides. It is shown that the performance of the structure as a filter strongly depends on the asymmetry of the rectangular structure. An analytical model based on the analogy between MDM waveguides and the microwave transmission line is used to...

Since investigation of scattering and penetrating of EM fields by objects such as multilayer structures are main challenges which researchers are facing in EMC and biological issues, the aim of this work is to present an analytical method for analysis of multilayer strips with finite width. Scattering properties of a lossy multilayer strip illumina...

A novel method for beam focusing in plasmonic lenses with an array of nanoslits perforated on a thin metallic film is proposed. Modifying the nanoslits with perpendicular cuts is utilized to change the effective length of the nanoslits which provides the possibility of manipulating the phase front profile based on the propagation property of the Su...

The concept of plasmonic nanoantennas is based on using nano-structures to confine light in nanometer scale. In this paper, we study the scattering property of ellipsoidal particles at optical frequencies. Numerical results illustrate how the Extinction Cross Section of ellipsoidal core-shelled nanostructures depends on shape and dimension. As a si...

A class of nano-scale wavelength-selective optical filters is proposed where the core of a metal-insulator-metal square ring is replaced with a split-ring core (SRC). The proposed resonator supports split-ring-resonator-like (SRR-like) resonant modes that are characteristics of the structure. These resonant modes are highly adjustable, via the gap...

In this paper, we study the effect of changing different parameters on the resonant behavior of a single element nanoantenna in the form of multilayer nanosphere. Thickness and number of layers are parameters that their variations have been focused. As nal step, the gradual transformation from sphere to ellipsoid has been considered. This alteratio...

A theoretical and numerical investigation of tunable plasmonic nano-optic lens on the basis of liquid crystal are proposed as a new method of active modulating the output beam. The focal length can be controlled easily by exposing plasmonic nano-optic lens to constant external electric field. The physical principle of this phenomenon is evaluated f...

A nanoplasmonic loop–stub structure is proposed. Its fundamental properties are studied and compared with those of single-stub and double-stub structures of similar structural parameters. The results show that loop–stub structure has two sets of resonances. One set is similar to the resonances of single-stub and double-stub structures; these resona...

The electrical control of beam focusing via a plasmonic lens which is composed of an array of nanoslits perforated on a thin metallic film is presented. We use 4-dimethylamino-N-methyl-4-stilbazolium tosylate (DAST), an organic material with a large electro-optical (EO) coefficient, as an incorporated material in the nanoslits to modulate the outpu...

A class of nanoplasmonic loaded slot cavities composed of a silver nano-rod placed in the center of a MIM slot cavity is introduced. Based on the nanocircuit concepts and transmission-line theory, a circuit-model for the loaded structure is proposed. The numerical results together with the theoretical analysis show that the proposed nanostructure o...

Embedding anisotropic media in the slit region of a plasmonic nano-optic lens is proposed as a new method of actively modulating the output beam. The focal length can be controlled easily by exposing the plasmonic nano-optic lens to a constant external electric field. The physical principle of this phenomenon is evaluated from the phase of surface...

A new configuration of the dual-band and dual-polarized antenna is presented, which is fed by aperture coupling for the existing mobile communication systems working over 870-960 MHz (GSM) and 1710-2180 MHz (DCS/UMTS) frequency band. XX-Polar antenna stands for an antenna with dual-band and dual linear slant polarization. In this paper DU band stan...

We numerically demonstrate the performance of a plasmonic lens composed of an array of nanoslits perforated on thin metallic film with slanted cuts on the output surface. Embedding Kerr nonlinear material in nanoslits is employed to modulate the output beam. A two dimensional nonlinear-dispersive finite-difference time-domain (2D N-D-FDTD) method i...

We numerically demonstrate the performance of a plasmonic lens composed of an array of nanoslits perforated on thin metallic film with slanted cuts on the output surface. Embedding Kerr nonlinear material in nanoslits is employed to modulate the output beam. A two dimensional nonlinear-dispersive finitedifference time-domain (2D N-D-FDTD) method is...

Having nonzero Poynting vector and Minkowski momentum density vector (MMDV) which cast positive projections onto each other is a necessary condition for electromagnetic fields to propagate in a medium. So it can be a basis to classify media where electromagnetic fields cannot propagate. As an example, the real and imaginary parts of the MMDV of hom...

The behavior of electromagnetic fields near the edge of a plasmonic wedge is investigated. We study the scattering properties, field divergence, and field enhancement near an Au wedge bounded by SiO 2 upon illumination by TM-polarized light using hypersingular integral equations, as a function of wavelength, wedge angle, and angle of incidence. The...

A type of tunable plasmonic lens with nanoslits is proposed for subwavelength imaging. The nanoslits array in the plasmonic lens, which have constant depths but varying widths, could generate desired optical phase retardations based on the particular propagation property of the Surface Plasmon Polaritons (SPPs) in the metal-insulator-metal slit wav...

In this work we introduce a symmetric waveguide intersection in photonic crystal structures, which passes the optical power entering from each one of its four ports, directly to the forward port. This junction allows designers to easier and more efficient design of photonic integrated circuits (PICs) and to create bridge-junctions in a 13.3μm2 area...

A new surface plasmon resonator, in the form of a metal cylinder shaped like a teardrop, is proposed and modeled using hypersingular integral equations. Illuminating the apex of the teardrop along its axis of symmetry with TM-polarised light excites equal-magnitude surface plasmons counter-propagating around its periphery. Interference of these cou...

A nanoplasmonic optical filtering technique based on a complementary split-ring resonator structure is proposed. The basic and modal properties of the square-nanoring are studied using the group theory. Degeneracy and non-degeneracy of the possible TM odd- and even-modes are characterized based on the symmetry elements of the ring structure. Distin...

A nanoplasmonic optical filtering technique based on a complementary split-ring resonator structure is proposed. The basic and modal properties of the square-nanoring are studied using the group theory. Degeneracy and non-degeneracy of the possible TM odd- and even-modes are characterized based on the symmetry elements of the ring structure. Distin...

In this numerical study, we present and demonstrate a compact, electrical plasmonic beam-steering device composed of anisotropic material. The splitting angle can be modulated by the external electric or magnetic field. The physical principle of this phenomenon is evaluated from the phase of surface plasmon polaritons and Fabry–Perot (F-P) resonanc...

In this paper, we propose a photonic crystal multi-channel drop filter based on ring resonators and investigate its properties numerically by using the finite-difference time-domain (FDTD) method. This structure is constructed in a two-dimensional square lattice. Our multi-channel drop filter is composed of three waveguides and three ring resonator...

A new configuration of the dual-band and dual-polarized antenna is presented, which is fed by aperture coupling for the existing mobile communication systems working over 870–960 MHz (GSM) and 1710–2180 MHz (DCS/UMTS) frequency band. In this paper DU band stands for DCS/UMTS band. Measurement results show that the proposed antenna yields good broad...

A reconstruction method for 1-D dielectric Scatterers using cosine and spline expansions with Differential Evolution and Particle Swarm Optimization is presented. Cubic spline and cosine expansion are compared. Two optimization methods, differential evolution (DE) and particle swarm optimization (PSO) in solving 1-D inverse scattering problems are...

In this study, a two-step method for estimation of location and electromagnetic profile parameters of an unknown 2D mass based on inverse scattering method is presented. FDTD is used as an EM solver and particle swarm optimization is the employed optimization method. For increasing the accuracy of solution, we present a method to select an optimum...

Four optimization methods are considered as the solver of inverse scattering problem. Under unique condition and for two different profiles the inverse problem is solved. The reconstruction errors for permittivity and conductivity and reconstruction time are the evaluating criteria. For two scenarios this criteria are presented.

We have established a different method to analyze various electromagnetic media. An analytical investigation has been carried out into the relation between the phase velocity, momentum density vector (MDV), and Poynting vector of plane waves in linear, homogeneous, and time-invariant media. Based on it, we have derived a novel dispersion relation f...

The design of an antipodal Vivaldi antenna for ultra wideband (UWB) applications is presented. The main purpose of this design is the reduction of three parameters of transient distortion, reflection coefficient and cross polarization level. Multi-objective particle swarm optimization (MOPSO) is applied to handle these objectives simultaneously. Al...

In this paper, we present a method for hiding large spheres. Our proposed coating can make a significant reduction in backscattering cross section of an electrically large sphere. Since the monostatic radar cross section (RCS) is based on backscatter waves, such a coated sphere cannot be detected by this kind of radars. Also the effect of loss is c...

The dyadic Green’s function of a PEMC cylinder is derived with the aid of the principle of scattering superposition and Ohm–Rayleigh method. The PEMC boundary conditions are presented in dyadic form and it shows that how the impedance parameter of PEMC and cross-polarized fields appear in the Green’s function. The asymptotic expansions of the dyadi...

In this study, we describe characteristics of plasmonic filters based on stubs coupled perpendicularly to metal–insulator–metal waveguides. To achieve a desirable filter, a designing procedure is proposed based on impedance curves, which lead to responses with great accordance to those obtained by numeric techniques. We study the impact of stub len...

Partial discharge in transformer can be detected and localized on-line using UHF technique. The first step for achieving this goal particularly the PD localizing is creation of simulation environment. In this paper three dimensional simulation is done using the FDTD method. The created simulation environment by FDTD was compared with CST software....

A novel array of a corner-cube reflector antenna targeting the 10.7-13.5-GHz frequency band is presented. The proposed antenna has the advantages of low-profile, broadband and high gain with linear polarisation. The substrate integrated waveguide (SIW) technology is employed effectively for feeding the antenna. The proposed antenna is formed of fou...

Phase and group velocities of plane waves may have different directions in a linear and homogeneous medium. This difference may lead to interesting situations such as the phase reversal propagation and the orthogonal phase velocity. Although the former has been analyzed in depth and it has found many applications, the latter has been left as a hypo...

We propose optical cross connect filters using photonic crystal ring resonators coupled waveguide crossings. We investigate the properties of this component numerically by using the finite-difference time-domain method. Our simulations reveal that the photonic crystal based cross connect filter has more than 92% normalized transmission. Extending o...

In this paper, we numerically study both band-pass and band-stop plasmonic filters based on Metal-Insulator-Metal (MIM) waveguides and circular ring resonators. The band-pass filter consists of two MIM waveguides coupled to each other by a circular ring resonator. The band-stop filter is made up of an MIM waveguide coupled laterally to a circular r...

In this study, a compact nanoscale plasmonic filter which consists of two metal–insulator–metal (MIM) waveguides coupled to each other by a rectangular ring resonator is presented and investigated numerically. The propagating modes of surface plasmon polaritons (SPPs) are studied in this structure. By replacing a portion of the ring core with air,...

Since introducing plasmonic material, lots of efforts have been made to design and fabricate metallic optical structures by Ag and Au. These structures are used to overcome previous limitations such as guiding optical waves below the diffraction limit. A variety of plasmonic waveguides such as V-grooves, wedges, gaps, ring resonators, micro-cavitie...

In this paper, we introduced implementation of stub filter in plasmonic array nanoparticle. The frequency range of our work is 300-1000 nm. To calculate transmission response we divide powers in port B to A. Our simulations show that we can achieve a drop in transmission response similar to what happens in stub structures embedded in MIM waveguides...

In this chapter, we investigate two dimensional (2D) photonic crystal ring resonators (PCRRs) which can be applicable to various photonic integrated circuits such as add-drop filters, channel-drop filters, power dividers, and wavelength demultiplexers. Mechanisms of these devices are based on the ring resonators resonances which occur due to the wa...

In this numerical study, we present a tunable photonic crystal optical filter design composed of anisotropic material. Various tunable optical filters which are composed of point and line defects in a square lattice of dielectric rods, with selective infiltration of some of the rods with anisotropic material, are presented. Our numerical simulation...

We have combined the two fundamental conservation theorems in electromagnetic theory-the energy and the momentum conservation theorems-to derive a vector wave equation for linear and homogeneous media with symmetrical constitutive matrix. We have demonstrated how the relation between the Poynting vector and the momentum density vector affects the e...

In this paper, Finite-Difference Time-Domain (FDTD) calculation of Maxwell's equations for simulation of Raman gap soliton is used. We investigated the generation of stationary gap solitons as well as slow gap solitons due to Raman shift in the one-dimensional photonic crystal. It is shown that by different intensities of the pump pulse, the genera...

Exact equations for second harmonic generation in a left-handed metamaterial (LHM) with cubic nonlinear response in the general case of phase mismatching are presented.It is demonstrated that special case of perfect phase matching condition lead to a spatial soliton solution.

An ultrawideband (UWB) antenna array was designed to optimize the beamwidth of the time-domain radiation pattern as well as the side lobe level. Multi-objective particle swarm optimization (MOPSO) was applied in dealing with these two conflicting objectives and finding the optimum trade-offs (Pareto front). Mutual coupling was not considered in the...

Antennas with dual linear slant polarization are necessary for modern personal communication base station applications. X-Polar antenna stands for an antenna with dual linear slant polarization. The most significant feature of the proposed antenna is high isolation between two different polarizations. The structure used here includes a reflector, a...

A method to obtain optimum tradeoffs (Pareto front) between sidelobe level (SLL) and beamwidth (BW) in time domain for ultrawideband (UWB) antenna arrays is presented. Multiobjective particle swarm optimization (MOPSO) is used to deal with these two conflicting objectives. In the optimization process, mutual coupling effects between elements are no...

The dispersion relation is derived for the most general con-figuration of a passive and reciprocal periodically loaded transmission line in a unique and simple form by introducing two novel parameters. Based on this relation, the phase and group velocities are determined and a simple condition for phase reversal propagation is obtained. The two abo...

To design less costly and time consuming photonic crystal fibers it is better to use empirical relations method instead of scalar effective index method and fully vectorial effective index method. Comparing them with accurate and powerful methods like full-vector finite element method, we find that empirical relations method has less error than two...

In this paper, we investigate bi-periodic photonic crystal structures, including photonic crystal waveguides, bends and splitters. In these structures, periodicity of the two rows next to guiding region altered. It is shown that bi-periodic structures can show much better performances compared to their conventional counterparts. Then a new bi-perio...

This paper presents a novel multi-objective optimization of printed microstrip-fed monopole antenna for ultra wideband (UWB) applications. Two objectives considered in this design are: low return loss and low transient distortion. By applying this method, a set of optimum antennas are achieved instead of a single design. Frequency and time domain p...

This article appeared in a journal published by Elsevier. The attached copy is furnished to the author for internal non-commercial research and education use, including for instruction at the authors institution and sharing with colleagues. Other uses, including reproduction and distribution, or selling or licensing copies, or posting to personal,...

We present an evolutionary design process of a photonic crystal notch filter using a particle swarm optimization (PSO) algorithm in conjunction with finite-difference time domain (FDTD). The notch-filter parameter is optimized by PSO, and a fitness function is evaluated by FDTD simulations to represent the performance of each candidate design. Usin...

The properties of a wideband photonic crystal power splitter with different output power levels based on directional coupling are investigated numerically with the finite-difference time-domain method. The effects of changing the coupling length and radius of the coupling rods between parallel waveguides on output transmissions are investigated. By...

We present a photonic-crystal (PC) channel-drop filter (CDF) design based on 3x3 PC ring resonators. The normalized transmission spectra for single-ring and dual-ring configurations have been investigated using two-dimensional finite-difference time-domain (FDTD) technique in a square-lattice dielectric-rod PC structure. First, we investigate a sin...

This paper presents a novel multi-objective optimization of printed microstrip-fed monopole antenna for ultra wideband (UWB) applications. Two objective functions are minimized in this design: return loss and transient distortion. Using this method, a set of optimum antennas are achieved instead of a single design. Optimization is performed to redu...

In this paper, enhancement of coupling and transport of energy in two 2-dimensional plasmonic waveguides, with finite and infinite number of nanoparticles, are investigated. Furthermore, the effect of edges on highly field localization and coupling between plasmons are studied.

This paper introduces High Impedance Electromagnetic Surfaces and investigates the performance of monopole antenna embedded on a High Impedance Ground plane. The HIS has an obvious surface wave Band Gap. Suppression of surface wave is used to improve antennas radiation pattern and Back lobe level reduces. For producing HIS we use periodic structure...

In this paper, theoretical and numerical analysis of low-loss right angle waveguide bends and T-junctions based on ultra-compact photonic crystal ring resonators (PCRR) is presented. Desirable characteristics are obtained by designing the waveguide bends and T-junctions as low-Q resonant cavities with certain symmetries and small radiation loss. A...

We propose a new scheme for an efficient photonic crystal 90° bend and power splitter. First we design a 90° bend by placing a super defect at the junction of two orthogonal photonic crystal waveguides. We changed the parameters of the super defect to optimize the transmission coefficient of the bent structure. Our twodimensional (2D) simulations s...

We propose coupled-mode analysis of a two-dimensional photonic crystal add-drop filter based on ring resonators, which can be applicable to photonic integrated circuits. Mechanism of this proposed add-drop filter is analogous to that of ring resonators resonance, which involves interaction of waveguides and resonators. Simulation results of this fi...

In this study, we present a photonic crystal Add-Drop Filter (ADF) design based on 3x3 ring resonators. The normalized transmission spectra for single-ring and dual-ring configurations have been investigated by using the two-dimensional Finite-Difference Time-Domain (FDTD) technique in a square lattice dielectric-rod photonic-crystal structure. In...

Cited By (since 1996): 1, Export Date: 11 June 2012, Source: Scopus

In this study, we propose a new type of photonic crystal band-pass and band-stop filter based on biperiodic structure. Usually two types of photonic crystal band-pass filters are utilized in optical circuit. In the first one Fabry-Perot cavities are used while in the second one cavity-coupled waveguide are used. We optimize the second structure in...

In this paper, we demonstrate a new type of 2D photonic crystal T-shaped channel-drop filters based on ring resonators with high normalized transmission; we investigate parameters which affects resonant frequency in these channel-drop filters. These parameters include dielectric constant of inner rods, coupling rods and whole rods of the structure...