Elshurafa, Amro M.; Radwan, Ahmed Gomaa Ahmed; Emira, Ahmed A.; Salama, Khaled N.(2014-08-28)[Patent]
In accordance with the present disclosure, one embodiment of a fractal variable capacitor comprises a capacitor body in a microelectromechanical system (MEMS) structure, wherein the capacitor body has an upper first metal plate with a fractal shape separated by a vertical distance from a lower first metal plate with a complementary fractal shape; and a substrate above which the capacitor body is suspended.
Zidan, Mohammed A.; Eltawil, Ahmed M.; Fahmy, Hossam A.H.; Kurdahi, Fadi; Salama, Khaled N.(IEEE Transactions on Nanotechnology, Institute of Electrical and Electronics Engineers (IEEE), 2014-06-18)[Article]
In this paper, we introduce for the first time, a closed-form solution for the memristor-based memory sneak paths without using any gating elements. The introduced technique fully eliminates the effect of sneak paths by reading the stored data using multiple access points and evaluating a simple addition/subtraction on the different readings. The new method requires fewer reading steps compared to previously reported techniques, and has a very small impact on the memory density. To verify the underlying theory, the proposed system is simulated using Synopsys HSPICE showing the ability to achieve a 100% sneak-path error-free memory. In addition, the effect of quantization bits on the system performance is studied.
In this paper, we propose an energy-efficient 13-bit capacitive sensor interface circuit. The
proposed design fully relies on successive approximation algorithm, which eliminates the
need for oversampling and digital decimation filtering, and thus low-power consumption is
achieved. The proposed architecture employs a charge amplifier stage to acheive parasitic
insensitive operation and fine absolute resolution. Moreover, the output code is not
affected by offset voltages or charge injection. The successive approximation algorithm is
implemented in the capacitance-domain using a coarse-fine programmable capacitor array,
which allows digitizing wide capacitance range in compact area. Analysis for the maximum
achievable resolution due to mismatch is provided. The proposed design is insensitive to
any reference voltage or current which translates to low temperature sensitivity. The operation
of a prototype fabricated in a standard CMOS technology is experimentally verified
using both on-chip and off-chip capacitive sensors. Compared to similar prior work, the
fabricated prototype achieves and excellent energy efficiency of 34 pJ/step.
Mansingka, Abhinav S.; Zidan, Mohammed A.; Barakat, Mohamed L.; Radwan, Ahmed Gomaa; Salama, Khaled N.(Microelectronics Journal, Elsevier BV, 2014-06-18)[Article]
This paper introduces fully digital implementations of four di erent systems in the 3rd order jerk-equation based chaotic family
using the Euler approximation. The digitization approach enables controllable chaotic systems that reliably provide sinusoidal or
chaotic output based on a selection input. New systems are introduced, derived using logical and arithmetic operations between
two system implementations of different bus widths, with up to 100x higher maximum Lyapunov exponent than the original jerkequation
based chaotic systems. The resulting chaotic output is shown to pass the NIST sp. 800-22 statistical test suite for pseudorandom
number generators without post-processing by only eliminating the statistically defective bits. The systems are designed
in Verilog HDL and experimentally verified on a Xilinx Virtex 4 FPGA for a maximum throughput of 15.59 Gbits/s for the native
chaotic output and 8.77 Gbits/s for the resulting pseudo-random number generators.
Mansingka, Abhinav S.; Radwan, Ahmed Gomaa; Salama, Khaled N.; Zidan, Mohammed A.(2013 IEEE 56th International Midwest Symposium on Circuits and Systems (MWSCAS), Institute of Electrical and Electronics Engineers (IEEE), 2014-06-18)[Conference Paper]
This paper introduces a generalized fully digital
hardware implementation of 1-D, 2-D and 3-D multiscroll chaos
through sawtooth nonlinearities in a 3rd order ODE with the
Euler approximation, wherein low-significance bits pass all NIST
SP. 800-22 tests. The low-significance bits show good performance
as spreading code for multiple-access DS-CDMA in AWGN and
multipath environments, equivalent to Gold codes. This system
capitalizes on complex nonlinear dynamics afforded by multiscroll
chaos to provide higher security than conventional codes
with the same BER performance demonstrated experimentally
on a Xilinx Virtex 4 FPGA with logic utilization less than 1.25%
and throughput up to 10.92 Gbits/s.
Radwan, Ahmed Gomaa; Mansingka, Abhinav S.; Salama, Khaled N.; Zidan, Mohammed A.(2013 IEEE 20th International Conference on Electronics, Circuits, and Systems (ICECS), Institute of Electrical and Electronics Engineers (IEEE), 2014-06-18)[Conference Paper]
This paper presents a digital implementation of a 3rd order chaotic system using the Euler approximation. Short-term predictability is studied in relation to system precision, Euler step size and attractor size and optimal parameters for maximum performance are derived. Defective bits from the native chaotic output are neglected and the remaining pass the NIST SP. 800-22 tests without post-processing. The resulting optimized pseudorandom number generator has throughput up to 17.60 Gbits/s for a 64-bit design experimentally verified on a Xilinx Virtex 4 FPGA with logic utilization less than 1.85%.
Sana, Furrukh; Ballal, Tarig; Al-Naffouri, Tareq Y.; Hoteit, Ibrahim(Biomedical Signal Processing and Control, Elsevier BV, 2014-03)[Article]
In this paper; we present a comprehensive scheme for wireless monitoring of the respiratory movements in humans. Our scheme overcomes the challenges low signal-to-noise ratio, background clutter and high sampling rates. It is based on the estimation of the ultra-wideband channel impulse response. We suggest techniques for dealing with background clutter in situations when it might be time variant. We also present a novel methodology for reducing the required sampling rate of the system significantly while achieving the accuracy offered by the Nyquist
rate. Performance results from simulations conducted with pre-recorded respiratory signals demonstrate the robustness of our scheme for tackling the above challenges and providing a low-complexity solution for the monitoring of respiratory movements.
This paper presents a study of FeNi-based thin film materials deposited with Mo, Al and B using a co-sputtering process. The existence of soft magnetic properties in combination with strong magneto-mechanical coupling makes these materials attractive for sensor applications. Our findings show that FeNi deposited with Mo or Al yields magnetically soft materials and that depositing with B further increases the softness. The out-of-plane magnetic anisotropy of FeNi thin films is reduced by depositing with Al and completely removed by depositing with B. The effect of depositing with Mo is dependent on the Mo concentration. The coercivity of FeNiMo and FeNiAl is reduced to less than a half of that of FeNi, and a value as low as 40 A/m is obtained for FeNiB. The surfaces of the obtained FeNiMo, FeNiAl and FeNiB thin films reveal very different morphologies. The surface of FeNiMo shows nano-cracks, while the FeNiAl films show large clusters and fewer nano-cracks. When FeNi is deposited with B, a very smooth morphology is obtained. The crystal structure of FeNiMo strongly depends on the depositant concentration and changes into an amorphous structure at a higher Mo level. FeNiAl thin films remain polycrystalline, even at a very high concentration of Al, and FeNiB films are amorphous, even at a very low concentration of B. 2014 by the authors.
Hussain, Aftab M.; Singh, Nirpendra; Fahad, Hossain M.; Rader, Kelly; Schwingenschlögl, Udo; Hussain, Muhammad Mustafa(Journal of Applied Physics, AIP Publishing, 2014-12-14)[Article]
We present a novel semiconducting alloy, silicon-tin (SiSn), as channel material for complementary metal oxide semiconductor (CMOS) circuit applications. The material has been studied theoretically using first principles analysis as well as experimentally by fabricating MOSFETs. Our study suggests that the alloy offers interesting possibilities in the realm of silicon band gap tuning. We have explored diffusion of tin (Sn) into the industry's most widely used substrate, silicon (100), as it is the most cost effective, scalable and CMOS compatible way of obtaining SiSn. Our theoretical model predicts a higher mobility for p-channel SiSn MOSFETs, due to a lower effective mass of the holes, which has been experimentally validated using the fabricated MOSFETs. We report an increase of 13.6% in the average field effect hole mobility for SiSn devices compared to silicon control devices.
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