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Finite-difference time-domain (FDTD) method is one of the most popular computational methods for solving electromagnetic problems. The common platforms for FDTD simulations all this while are usually the computers or workstations. Exploiting the increasing computational capacity of smart hand-held mobile devices, multiple one-dimensional (M1-D) FDTD method is developed to perform electromagnetic simulation...
With the aim of increasing the numerical methods' precision regarding Maxwell's equations solving, a third order staggered FDTD method is proposed in this paper. The proposed method offers a trade-off between the accuracy and the stability, through the application of a third order staggered backward differentiation for the approximation of the temporal partial derivatives, and a fourth-order central...
Second-harmonic generation (SHG) has been used for demonstrating nonlinear electromagnetic responses in different materials. In this paper, the SHG in a semiconductor layer is studied under microwave and terahertz frequencies. The hydrodynamic nonlinear Drude model is implemented in the semiconductor layer to model the interactions between the carriers and the electromagnetic fields. A numerical algorithm...
A 3D split-step Fourier method is presented and tested. It is based on a spectral representation of the discrete wave equation in cylindrical coordinates. The formulations in this method are self-consistent in the discrete domain. This method is applied to simulate the propagation with ducts retrieved after clutter data inversion. In the numerical tests, the difference between N × 2D and 3D models...
In this paper, we used two type of high gain antennas in external RF electromagnetic environment (EME) testing system which was the most important part in the electromagnetic environment effects (E3) system testing. The first one was S band pyramidal horn antenna had wider beam width in 2GHz to 4GHz, and the other one was parabolic antenna had higher gain in the same frequency band. From using these...
In order to study the charging characteristics of aerospace dielectric materials and analyze the influence of the material thickness on the equilibrium potential and the charging time, the differential equation of the surface potential is obtained. The charging expression of the ground simulation space charged process can be attained by solving the differential equation, the simulation curves comparing...
This paper concentrates on the surface integral equation (SIE) based on boundary equivalence principle evaluating second-harmonic (SH) generation from noble metal nanoparticles with arbitrary shapes. By invoking the proposed principle, the number of unknowns will reduce to half compared with the surface integral equation based on Love's equivalence principle with the same problem. Simultaneously,...
Accurate modeling of planar transmission line is very important in microwave communication and radar systems, especially at high frequencies. The present paper computes the conductor loss of planar transmission line in full-wave band by the method of lines considering the surface roughness. The new concept presented here derives a complex surface impedance from conductivity Gradient Model, reflecting...
In this paper, a maximum efficiency extracting technique is presented for endoscopic capsule's Wireless Power Transfer (WPT). Instead of conventional regulators, a DC-DC Bulk LTC3129-1 with Maximum Power Point Control (MPPC) capability is adopted to boost the power conversion efficiency of the WPT receiver (including RF-DC rectifier and DC-DC Converter) up to 60%. Measurements validate that DC-DC...
In this paper we propose a new dual-stop-band frequency selective surface (FSS) for infrared stealth applications. The simulated results show that the proposed dual-stop-band FSS has high reflectivity in the two atmospheric windows (3.0–5.0μm and 8.0–14.0μm) for normal incidence waves, and the transmissvity is suppressed completely under 0.1.
Angle measurement of monopulse is widely used in the angle tracing technique for high precision tracking radar system. This paper analyzes some facts related with precision of angle measurements in monopulse radar, including offset angle of sub-beams, squint angle between target and centerline of main beam, receiver output noise, and target amplitude fluctuation. A new method for angle measurement...
In the paper, the problem of fast multi-objective optimization of compact impedance matching transformers is addressed by utilizing a novel Pareto ranking bisection algorithm. It approximates the Pareto front by dividing line segments connecting the designs found in the previous iterations, and refining the obtained candidate solutions by means of poll-type search involving Pareto ranking. The final...
This paper proposes a printable chipless tag that encodes more bits than a conventional tag, and also a dual circularly polarized (CP) reader that achieves high isolation as well as insensitive orientation. To demonstrate this concept, a radio-frequency identification (RFID) tag with a compact size of 12mm × 12mm is designed to encode 8 bits covering 6–9 GHz, and is investigated with dual-CP backscattering...
This work addresses directivity improvement of a fan-beam antenna using local constrained optimization. More specifically, it demonstrates that adjustment of elementary patch sizes of a gridded patch antenna considerably improves antenna directivity without increasing its footprint. This indicates that utilization of all available degrees of freedom, i.e., genetic algorithm (GA) optimization and continuous...
A microstrip ring antenna is optimized for non-invasive blood glucose monitoring. The main objective is to maximize the sensitivity of antenna w.r.t. the change of concentration of aqueous glucose solution. The parameterized antenna model and solution model are simulated in CST Microwave Studio in order to evaluate the sensitivity of the antenna design. The design process is implemented through a...
In this paper, direction of arrival (DOA) estimation using sum co-array of coprime arrays is studied. The array geometry can be represented as the kronecker product of those of two coprime arrays. This array structure can reduce the aperture loss when extracting the subarrays, which are jointly used to achieve high resolution and unique DOA estimation via low computational propagator method. Compare...
The application of miniaturized indefinite magnetic metamaterial lens (IMML) in wireless power transfer (WPT) are numerically investigated. Vibrations of efficiency can be observed by sweeping the geometrical size or permeability of the IMML. By optimizing the parameters of IMML, the volume of the metamaterial lens can be miniaturized to the extent in which the lens is portable and flexible enough...
Simulation of graphene-GaAs Schottky junction solar cell with graphene gate is performed by using finite difference method. Poisson and driftdiffusion equations are solved self-consistently to capture carrier dynamics in the solar cell. Our algorithm is verified by comparing with experimental results. The Schottky barrier between graphene and GaAs can be tuned by graphene gate, and hence the open...
In this paper, a compact size dual-polarized high-gain resonant cavity antenna (RCA) at 28 GHz is presented. The RCA consists of two layers of substrates. The upper layer is composed of a square patch-type frequency selective surface (FSS), a dual-polarized microstrip patch antenna fed by two coaxial SMA connectors is placed onto the lower substrate as the feeding system. The electromagnetic waves...
This paper simulates scattering properties of metasurfaces by finite difference time domain(FDTD) method with generalized sheet transition conditions (GSTCs) to alleviate computational burden. It is found that a metasurface can be represented by the electric and magnetic polarization densities, which is related to electromagnetic field by GSTCs. The GSTCs are thereby implemented in 3D FDTD codes and...
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