Ahmad Hakimi

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SUMMARY Although, the finite element method numerically is efficient it exhibits difficulties whenever the remeshing of the analysis domain must be performed. For such problems, utilizing meshless computation methods is very promising. But, their large computational cost, which arises from following a time-consuming process to find shape functions, is one(More)
— In this paper, an improved meshless method is presented by eliminating the time consuming process of determining the shape function. We introduce a direct approach, based on the properties, which is required for any shape function, to prepare the shape function and propose a new meshless method. The proposed method does not need to any predetermined basis(More)
SUMMARY An improved truly meshless method is presented for three-dimensional (3D) electromagnetic problems. In the proposed method, the computational time for the construction of the introduced shape function is lower than the other meshless methods considerably. An efficient and stable nodal integration technique based on the Taylor series extension is(More)
—A new configuration of wideband bandpass filter (BPF) with notched bands is presented. Proposed BPF is based on stepped-impedance resonator. By utilizing dual stepped-impedance resonators in folded topology a rectangular-ring resonator is formed. Two notched bands in the passband are achieved without using asymmetrical coupled lines. In other words, the(More)
—The intriguing characteristics of chaotic maps have prompted researchers to use these sequences in watermarking systems to good effect. In this paper we aim to use a tent map to encrypt the binary logo to arrive at a like-noise signal. This approach makes extraction of the watermark signal for potential attacker very hard. Embedding locations are selected(More)
In this paper, an ultra-broad bandwidth, low noise, and high gain-flatness CMOS distributed amplifier (CMOS-DA) based on a novel gain-cell is presented. The new gain-cell that enhances the output impedance as a result the gain substantially over conventional RGC is the improved version of Regulated Cascode Configuration (RGC). The new gain-cell based(More)
— In this paper a high gain and ultra-broadband CMOS distributed amplifier (CMOS-DA) utilizing standard 0.13 µm CMOS technology is presented. This design is based on a new gain cell that makes an ultra-broadband DA by considering the gain, noise figure (NF), input and output return losses concurrently. The new gain cell is the improved version of active(More)
In this paper, an ultra-wideband (UWB) common gate low-noise amplifier (LNA) with g m-boosted and noise-cancelling techniques is presented. In this scheme we utilize g m-boosted stage for cancelling the noise of matching device. The bandwidth extension and flat gain are achieved by using of series and shunt peaking techniques. Simulated in .13 um Cmos(More)