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A compact dual-band spiral antenna is proposed for on-body applications in this paper, operating at 402 MHz Medical Device Radiocommunications Service (MedRadio) band and 2.45 GHz Industrial, Scientific, and Medical (ISM) band. Initially, a spiral-shaped dipole is adopted to form a miniaturized wearable antenna resonant at 402 MHz to communicate with implanted devices. In addition, four rectangular...
The existing half-duplex relay-based device-to-device (D2D) communication equips with single antenna infrastructure and receives and transmits signals in two equivalent slots which lead to poor performance in term of rate achievement. To solve this problem, we propose a new relay-based D2D scheme with two-antenna infrastructure and bring in slot splitting factor to divide one frame into double unequal...
An efficient fully automated EM-level design framework is implemented using Matlab, Sonnetlab toolbox and Sonnet EM simulator for the design of different type of sequentially coupled resonator planar filters. The proposed implementation integrates the space mapping technique and reflected group delay method to achieve fast and reliable EM-based filter design. In this paper, two design examples are...
This paper presents the design of novel surface that can convert the incident EM-waves into its cross-polarized (orthogonal) component at millimeter wave frequencies. The unit cell composing the surface has a cut of wire along the diagonal with two closed rings above and below. The unit cell has three resonance frequencies at 84.32GHz, 85.6GHz, and 87.38GHz at which the polarization conversion reaches...
This paper proposes a single-layered dual-band patch antenna using a CRLH mushroom-like metamaterial structure. The antenna is compact, it can achieve maximum gains of 2.29 dBi at 2.76 GHz and 7.06 dBi at 4.27 GHz, with a monopole-like and a patch-like radiation pattern, respectively. The bandwidths for the reflection coefficient less than −10 dB are 28 MHz at the low frequency band and 130 MHz at...
Based on the equivalent source and NMM (numerical mode matching method), the theory model method of electromagnetic signal transmission for down-hole to surface by is established. The gap antenna and toroid were calculated, the influence of the input impedance and of incentive to drill string current is analyzed, through calculation and comparison that the gap antenna method is more suitable for the...
Water occurring on earth has always been equipped with the characteristic of frequency dispersive permittivity at microwave frequency, which thus can be seen as a promising constituent material for broadband electromagnetic wave absorption. Here, we develop water as ultrathin dielectric substrate standing on the metal backplane to construct three-dimensional grid array, which can acquire broadband...
This paper proposed a miniaturized wideband implantable antenna operating at MedRadio band for Medical Body Area Network (MBAN) devices. The operating frequency of the proposed antenna covers from 334 to 441 MHz for the simulated result, which is robust enough to withstand the frequency shift brought by different human beings. The footprint of the designed antenna covers a planar area of only 14 mm...
A novel wideband dual-polarized magneto-electric dipole unidirectional antenna is proposed in this paper. The antenna is composed of dual-layer magneto-electric (ME)-dipole and two Γ-shaped probes. Its two ports both achieve a common impedance bandwidth of 91.6%(SWR<2). The antenna has excellent performance in isolation, which is more than 15dB, and a high front-to-back ration more than 14.8dB...
A wideband microstrip endfire antenna is designed for applications in base station and satellite communication. Utilizing substrate integrated waveguide technology, vertically polarized wave is generated by the driven element of the antenna. And a parasitic microstrip patch with one edge opened and the other three edges shorted is introduced as the magnetic dipole to improve the impedance matching...
This paper presents a new technology to realize a millimeter wave antenna with circular polarization. The antenna has a complex structure which consists of several dielectric slabs to achieve wideband, high-gain performance. Thank to the 3D printing technologies, the complex antenna can be easily fabricated with low cost. The proposed antenna has a wide impedance bandwidth of 50% from 45 to 75 GHz...
Space mapping algorithm is an effective method to speed up optimization. Automatic optimization of space mapping algorithm is realized in this paper. Parallel multi-machine simulation technology is utilized to enhance the calculation efficiency. A microwave low-pass filter is optimized using the proposed algorithm. The efficiency is improved by about forty percent and it provides a new technical way...
This paper proposes an automated topology optimization technique for internal antenna design using an improved BPSO. A new transfer function with a time-variant transfer factor is proposed to improve the problem of easily falling into local optimum in conventional BPSO. Compact tri-band planar antenna design is presented, showing that the proposed technique significantly outperforms the previous topology...
Considering the factors of environmental adaptability, laying cost and system complexity, the signal fingerprint positioning based on RFID systems has become a better choice of the positioning technology. Online and offline signal matching technology is very important stage for the signal fingerprint positioning. In this paper, we propose a signal matching algorithm in order to further improve the...
Millimeter wave (mm-wave) radar system is widely utilized in detecting the Foreign Object Debris (FOD) at the airport runways due to its high resolution and low power. In this paper, a novel hierarchical FOD detection method is proposed based on eigenvalue spectrum feature extraction and minimax probability machine (MPM) for a 77GHz mm-wave radar system. The clutter map constant false alarm rate (CFAR)...
The parabolic equation (PE) method is derived from the wave equation, and it has been widely used to solve electromagnetic wave propagation problems. In recent years, it was realized that the PE method can also be applied to scattering problems. The PE method meets the demand for higher efficiency and accuracy at the same time when there are limited computational resources. In this paper, both co-polarized...
As an efficient and clean energy, microwaves have been widely used for industrial production. However, hot spots and thermal runaway have prevented the large-scale application of microwaves. In this paper, a new multiphysics model is proposed to solve the problem of non-uniform heating. In this model, electromagnetics and heat transfer are coupled to simulate the heating process. The sample is wrapped...
An optimized multiple layered plasma stealth model, with great electromagnetic (EM) wave absorption performance based on transmission line theory is proposed in this study. With employment of this multiple inhomogeneous layered plasma structure, EM waves absorption ability improves significantly compared with homogeneous ones. A wide EM wave frequency range, X band, interaction with this structure...
An equivalent circuit model for a multiple resonance reflectarray element is presents in this study. It allows predicting the broadband characteristics of the element from only a few full wave simulations. The equivalent circuit approach can provide good insight into the physical and design properties of periodic structure.
Microwave heating usually leads to non-uniform temperatures due to the existence of drastic variation of electric field. In this study, a numerical method combined with integral equation and spectrum analysis is proposed to find its generation condition. Results show that the electric field is generally unstable, and a tiny shift in microwave frequency, permittivity of dielectric object or cavity...
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