141 resultados para 291705 Microwave and Millimetrewave Technology


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The operation of a previously proposed terahertz (THZ) detector is formulated in detail. The detector is based on the hot-electron effect of the 2D electron gas (2DEG) in the quantum well (QW) of a GaAs/AIGaAs heterostructure. The interaction between the THz radiation and the 2DEG, the current enhancement due to hot -electron effect, and the noise performance of the detector are analyzed

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An electromagnetically coupled T-shaped microstrip feed used to enhance the impedance bandwidth of a rectangular microstrip antenna is reported. The proposed antenna offers a 2:1 VSWR bandwidth of -36% with an increase in gain of 0.8 dB

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compact microstrip antenna integrated with an amplifier having an area reduction of 70%, compared to the standard circular microstrip patch antenna, is presented. The antenna also provides an enhanced gain of 10-dB more than its passive counter part. The measured 2:1 VSWR band width is -4% at 790 MHz, which is 2.5 times larger than that of the passive microstrip antenna

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This work presents an explicit formulation for multiple- edge diffraction for mobile radiowave propagation in terms of uniform theory of diffraction (UTD) coefficients when a spherical incident wave is considered. This solution can be used in an UTD context and sharply reduces the computing time over existing formulation. Results can be applied in the planning of microcellular systems

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very-high-permittivity (e, = 100) multiband dielectrice> e resonator antenna is presented. The compact antenna, excited by a m:'crostrip line, resonates at two frequencies centered around the 1.9- GHz and 2.4-GHz bands with identical polarization . The behavior of the antenna at different positions along the feed line is studied and optimized. Multiple resonances with the same polarization and broad radioticn patterns suggest the suitability of the antenna for multiband wireless application

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A novel slope -strip feeding technique for a microstrip antenna is presented in order to achieve a broad bandwidth. The experimental results show that the optimal bandwidth attained is 53.4% for less than -10-dB return loss

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A novel technique for backscattering reduction for both TE and TM polarisation, employing a metallo-dielectric structure based on Sierpinski carpet fractal geometry, is reported. A reduction in backscattered power of --30 dB is obtained for normal incidence in the X-band for the structure using the third iterated stage of the fractal geometry

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A novel compact single-layer dual frequency microstrip antenna which uses an H-shaped geometry with two U-shaped slots embedded near the radiation edges, is presented. By changing the design parameters, the lower and higher resonant frequencies can be controlled easily, and a range of frequency ratios (1.716-2.363) can be obtained in this design. For the two operating frequencies of the proposed antenna, the same polarization planes and broadside radiation patterns are achieved. Compared to the regular dualfrequency patch antenna, this antenna can realize a significant size reduction

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A theoretical analysis of a symmetric T-shaped rnicrostripfed rectangular microstrip antenna using the finite-difference titnedoniain (FDTD) method is presented in this paper. The resonant frequency, return loss, impedance bandwidth, and radiation patterns are predicted and are in good agreement with the measured results

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The radiation characteristics of a microstrip-line-excited rectangular dielectric resonator antenna (DRA) are studied experimentally.The radiation charactristics and excitation of different modes are highly influenced by the orientation of the DR,feed line parameters ,and finite size of the ground plane

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This paper presents the outcome of the experimental studies performed on L-strip fed compact rectangular microstrip antenna. The effect of the feed parameters upon the characteristics of the antenna is studied in detail. The antenna offers an impedance bandwidth of nearly 20% and is suitable for broadband applications

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In this paper, a comparison study among three neuralnetwork algorithms for the synthesis of array patterns is presented. The neural networks are used to estimate the array elements' excitations for an arbitrary pattern. The architecture of the neural networks is discussed and simulation results are presented. Two new neural networks, based on radial basis functions (RBFs) and wavelet neural networks (WNNs), are introduced. The proposed networks offer a more efficient synthesis procedure, as compared to other available techniques

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A broadband cylindrical dielectric resonator antenna (DRA) energized with an L-strip feed is presented The novel exciting technique achieves a 2:1 VSWR bandwidth of 18%. The variation of bandwidth for different feed parameters is also studied

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In this paper, we introduce a novel feeding technique for bandwidth enhancement of a rectangular microstrip antenna This antenna offers an impedance bandwidth of 22% without degrading the effciencv. The effect of the feed parameters upon patch characteristics such as resonant frequency, impedance bandwidth, and radiation pattern are studied in detail. The experimental results are verified using the FDTD results

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rectangular low-density, high-permittivity dielectric resona or antenna (DRA) excited by T-shaped microstrip feed offering a 2:1 VSWR bandwidth of -22% at 2.975 GHz is reported. The design methoaology and experimental results of the antenna are discussed. The excellent gain and radiation performance of the proposed antenna project: it as a potential candidate for telecommunication applications