• A robust parasitic-insensitive successive approximation capacitance-to-digital converter

      Omran, Hesham; Arsalan, Muhammad; Salama, Khaled N. (Proceedings of the IEEE 2014 Custom Integrated Circuits Conference, Institute of Electrical and Electronics Engineers (IEEE), 2014-09) [Conference Paper]
      In this paper, we present a capacitive sensor digital interface circuit using true capacitance-domain successive approximation that is independent of supply voltage. Robust operation is achieved by using a charge amplifier stage and multiple comparison technique. The interface circuit is insensitive to parasitic capacitances, offset voltages, and charge injection, and is not prone to noise coupling. The proposed design achieves very low temperature sensitivity of 25ppm/oC. A coarse-fine programmable capacitance array allows digitizing a wide capacitance range of 16pF with 12.5-bit quantization limited resolution in a compact area of 0.07mm2. The fabricated prototype is experimentally verified using on-chip sensor and off-chip MEMS capacitive pressure sensor. © 2014 IEEE.
    • Low pull-in voltage electrostatic MEMS switch using liquid dielectric

      Zidan, Mohammed A.; Kosel, Jürgen; Salama, Khaled N. (2014 IEEE 57th International Midwest Symposium on Circuits and Systems (MWSCAS), Institute of Electrical and Electronics Engineers (IEEE), 2014-08) [Conference Paper]
      In this paper, we present an electrostatic MEMS switch with liquids as dielectric to reduce the actuation voltage. The concept is verified by simulating a lateral dual gate switch, where the required pull-in voltage is reduced by more than 8 times after using water as a dielectric, to become as low as 5.36V. The proposed switch is simulated using COMSOL multiphysics using various liquid volumes to study their effect on the switching performance. Finally, we propose the usage of the lateral switch as a single switch XOR logic gate.
    • An acoustic system for autonomous navigation and tracking of marine fauna

      De la Torre, Pedro; Salama, Khaled N.; Berumen, Michael L. (2014 IEEE 57th International Midwest Symposium on Circuits and Systems (MWSCAS), Institute of Electrical and Electronics Engineers (IEEE), 2014-08) [Conference Paper]
      A marine acoustic system for underwater target tracking is described. This system is part of the Integrated Satellite and Acoustic Telemetry (iSAT) project to study marine fauna. It is a microcontroller-based underwater projector and receiver. A narrow-band, passive sonar detection architecture is described from signal generation, through transduction, reception, signal processing and up to tone extraction. Its circuit and operation principles are described. Finally, a comparison between the current energy detection method versus an alternative matched filter approach is included.
    • Foldable neuromorphic memristive electronics

      Ghoneim, Mohamed T.; Zidan, Mohammed A.; Salama, Khaled N.; Hussain, Muhammad Mustafa (2014 14th International Workshop on Cellular Nanoscale Networks and their Applications (CNNA), Institute of Electrical and Electronics Engineers (IEEE), 2014-07) [Conference Paper]
      Neuromorphic computer will need folded architectural form factor to match brain cortex's folded pattern for ultra-compact design. In this work, we show a state-of-the-art CMOS compatible pragmatic fabrication approach of building structurally foldable and densely integrated neuromorphic devices for non-volatile memory applications. We report the first ever memristive devices with the size of a motor neuron on bulk mono-crystalline silicon (100) and then with trench-protect-release-recycle process transform the silicon wafer with devices into a flexible and semi-transparent silicon fabric while recycling the remaining wafer for further use. This process unconditionally offers the ultra-large-scale-integration opportunity-increasingly critical for ultra-compact memory.
    • Leakage analysis of crossbar memristor arrays

      Zidan, Mohammed A.; Salem, Ahmed Sultan; Fahmy, Hossam Aly Hassan; Salama, Khaled N. (2014 14th International Workshop on Cellular Nanoscale Networks and their Applications (CNNA), Institute of Electrical and Electronics Engineers (IEEE), 2014-07) [Conference Paper]
      Crossbar memristor arrays provide a promising high density alternative for the current memory and storage technologies. These arrays suffer from parasitic current components that significantly increase the power consumption, and could ruin the readout operation. In this work we study the trade-off between the crossbar array density and the power consumption required for its readout. Our analysis is based on simulating full memristor arrays on a SPICE platform.
    • Memristor based crossbar memory array sneak path estimation

      Naous, Rawan; Zidan, Mohammed A.; Salem, Ahmed Sultan; Salama, Khaled N. (2014 14th International Workshop on Cellular Nanoscale Networks and their Applications (CNNA), Institute of Electrical and Electronics Engineers (IEEE), 2014-07) [Conference Paper]
      Gateless Memristor Arrays have the advantage of offering high density systems however; their main limitation is the current leakage or the sneak path. Several techniques have been used to address this problem, mainly concentrating on spatial and temporal solutions in setting a dynamic threshold. In this paper, a novel approach is used in terms of utilizing channel estimation and detection theory, primarily building on OFDM concepts of pilot settings, to actually benefit from prior read values in estimating the noise level and utilizing it to further enhance the reliability and accuracy of the read out process.
    • 60 GHz system-on-chip (SoC) with built-in memory and an on-chip antenna

      Ghaffar, Farhan A.; Arsalan, Muhammad; Cheema, Hammad; Salama, Khaled N.; Shamim, Atif (The 8th European Conference on Antennas and Propagation (EuCAP 2014), Institute of Electrical and Electronics Engineers (IEEE), 2014-04) [Conference Paper]
      A novel 60 GHz transmitter SoC with an on-chip antenna and integrated memory in CMOS 65 nm technology is presented in this paper. This highly integrated transmitter design can support a data rate of 2 GBPS with a transmission range of 1 m. The transmitter consists of a fundamental frequency 60 GHz PLL which covers the complete ISM band. The modulator following the PLL can support both BPSK and OOK modulation schemes. Both stored data on the integrated memory or directly from an external source can be transmitted. A tapered slot on chip antenna is integrated with the power amplifier to complete the front end of the transmitter design. Size of the complete transmitter with on-chip antenna is only 1.96 mm × 1.96 mm. The core circuits consume less than 100 mW of power. The high data rate capability of the design makes it extremely suitable for bandwidth hungry applications such as unencrypted HD video streaming and transmission.
    • Fibonacci-based hardware post-processing for non-autonomous signum hyperchaotic system

      Mansingka, Abhinav S.; Barakat, Mohamed L.; Zidan, Mohammed A.; Radwan, Ahmed Gomaa; Salama, Khaled N. (2013 International Conference on IT Convergence and Security (ICITCS), Institute of Electrical and Electronics Engineers (IEEE), 2013-12) [Conference Paper]
      This paper presents a hardware implementation of a robust non-autonomous hyperchaotic-based PRNG driven by a 256-bit LFSR. The original chaotic output is post-processed using a novel technique based on the Fibonacci series, bitwise XOR, rotation, and feedback. The proposed post-processing technique preserves the throughput of the system and enhances the randomness in the output which is verified by successfully passing all NIST SP. 800-22 tests. The system is realized on a Xilinx Virtex 4 FPGA achieving throughput up to 13.165 Gbits/s for 16-bit bus-width surpassing previously reported CB-PRNGs. © 2013 IEEE.
    • Implantable intraocular pressure monitoring systems: Design considerations

      Arsalan, Muhammad; Ouda, Mahmoud H.; Marnat, Loic; Shamim, Atif; Salama, Khaled N. (2013 IEEE MTT-S International Microwave Workshop Series on RF and Wireless Technologies for Biomedical and Healthcare Applications (IMWS-BIO), Institute of Electrical and Electronics Engineers (IEEE), 2013-12) [Conference Paper]
      Design considerations and limitations of implantable Intraocular Pressure Monitoring (IOPM) systems are presented in this paper. Detailed comparison with the state of the art is performed to highlight the benefits and challenges of the proposed design. The system-on-chip, presented here, is battery free and harvests energy from incoming RF signals. This low-cost design, in standard CMOS process, does not require any external components or bond wires to function. This paper provides useful insights to the designers of implantable wireless sensors in terms of design choices and associated tradeoffs. © 2013 IEEE.
    • ISAT: The mega-fauna acoustic tracking system

      De la Torre, Pedro; Smith, Egan Lloyd; Sancheti, Ajay; Salama, Khaled N.; Berumen, Michael L. (2013 MTS/IEEE OCEANS - Bergen, Institute of Electrical and Electronics Engineers (IEEE), 2013-06) [Conference Paper]
      The acoustic tracking module of the Integrated Satellite and Acoustic Telemetry (iSAT) system is discussed in detail. iSAT is capable of detecting the relative direction of an acoustic source by measuring the order of arrival (OOA) of the acoustic signal to each hydrophone in a triangular array. The characteristics of the hydrophones, the projector, and the target acoustic signal used for iSAT are described. Initially it is designed to study the movements of whale sharks (Rhincodon typus), but it could potentially be used to describe high resolution movements of other marine species. © 2013 IEEE.
    • A 5.2GHz, 0.5mW RF powered wireless sensor with dual on-chip antennas for implantable intraocular pressure monitoring

      Arsalan, Muhammad; Ouda, Mahmoud H.; Marnat, Loic; Ahmad, Talha Jamal; Shamim, Atif; Salama, Khaled N. (2013 IEEE MTT-S International Microwave Symposium Digest (MTT), Institute of Electrical and Electronics Engineers (IEEE), 2013-06) [Conference Paper]
      For the first time a single chip implantable wireless sensor system for Intraocular Pressure Monitoring (IOPM) is presented. This system-on-chip (SoC) is battery-free and harvests energy from incoming RF signals. The chip is self-contained and does not require external components or bond wires to function. This 1.4mm3 SoC has separate 2.4GHz-transmit and 5.2GHz-receive antennas, an energy harvesting module, a temperature sensor, a 7-bit TIQ Flash ADC, a 4-bit RFID, a power management and control unit, and a VCO transmitter. The chip is fabricated in a standard 6-metal 0.18μm CMOS process and is designed to work with a post-processed MEMS pressure sensor. It consumes 513μW of peak power and when implanted inside the eye, it is designed to communicate with an external reader using on-off keying (OOK). © 2013 IEEE.
    • Memristor-based relaxation oscillators using digital gates

      Khatib, Moustafa A.; Fouda, Mohamed E.; Mosad, Ahmed G.; Salama, Khaled N.; Radwan, Ahmed G. (2012 Seventh International Conference on Computer Engineering & Systems (ICCES), Institute of Electrical and Electronics Engineers (IEEE), 2012-11) [Conference Paper]
      This paper presents two memristor-based relaxation oscillators. The proposed oscillators are designed without the need of any reactive elements, i.e., capacitor or inductor. As the 'resistance storage' property of the memristor can be exploited to generate the oscillation. The proposed oscillators have the advantage that they can be fully integrated on-chip giving an area-efficient solution. Furthermore, these oscillators give higher frequency other than the existing reactance-less oscillator and provide a wider range of the resistance. The concept of operation and the mathematical analysis for the proposed oscillators are explained and verified with circuit simulations showing an excellent agreement. © 2012 IEEE.
    • Effect of boundary on controlled memristor-based oscillator

      Fouda, Mohamed E.; Radwan, Ahmed Gomaa; Salama, Khaled N. (2012 International Conference on Engineering and Technology (ICET), Institute of Electrical and Electronics Engineers (IEEE), 2012-10) [Conference Paper]
      Recently, the applications of memristors have spread into many fields and especially in the circuit theory. Many models have been proposed for the HP-memristor based on the window functions. In this paper, we introduce a complete mathematical analysis of the controlled reactance-less oscillator for two different window functions of Joglekar's model (linear and nonlinear dopant drift) to discuss the effect of changing the window function on the oscillator's behavior. The generalized necessary and sufficient conditions based on the circuit elements and control voltages for both the linear and nonlinear models are introduced. Moreover, closed form expressions for the oscillation frequency and duty cycle are derived for these models and verified using PSPICE simulations showing an excellent matching. Finally a comparison between the linear and nonlinear models which shows their effect on the oscillation frequency and conditions of oscillation is introduced. © 2012 IEEE.
    • Impedance matching through a single passive fractional element

      Radwan, Ahmed Gomaa; Shamim, Atif; Salama, Khaled N. (Proceedings of the 2012 IEEE International Symposium on Antennas and Propagation, Institute of Electrical and Electronics Engineers (IEEE), 2012-07) [Conference Paper]
      For the first time, a generalized admittance Smith chart theory is introduced to represent fractional order circuit elements. The principles of fractional order matching circuits are described. We show that for fractional order α < 1, a single parallel fractional element can match a wider range of load impedances as compared to its series counterpart. Several matching examples demonstrate the versatility of fractional order series and parallel element matching as compared to the conventional approach. © 2012 IEEE.
    • Hardware realization of chaos based block cipher for image encryption

      Barakat, Mohamed L.; Radwan, Ahmed G.; Salama, Khaled N. (ICM 2011 Proceeding, Institute of Electrical and Electronics Engineers (IEEE), 2011-12) [Conference Paper]
      Unlike stream ciphers, block ciphers are very essential for parallel processing applications. In this paper, the first hardware realization of chaotic-based block cipher is proposed for image encryption applications. The proposed system is tested for known cryptanalysis attacks and for different block sizes. When implemented on Virtex-IV, system performance showed high throughput and utilized small area. Passing successfully in all tests, our system proved to be secure with all block sizes. © 2011 IEEE.
    • State space modeling of Memristor-based Wien oscillator

      Talukdar, Abdul Hafiz Ibne; Radwan, Ahmed G.; Salama, Khaled N. (ICM 2011 Proceeding, Institute of Electrical and Electronics Engineers (IEEE), 2011-12) [Conference Paper]
      State space modeling of Memristor based Wien 'A' oscillator has been demonstrated for the first time considering nonlinear ion drift in Memristor. Time dependant oscillating resistance of Memristor is reported in both state space solution and SPICE simulation which plausibly provide the basis of realizing parametric oscillation by Memristor based Wien oscillator. In addition to this part Memristor is shown to stabilize the final oscillation amplitude by means of its nonlinear dynamic resistance which hints for eliminating diode in the feedback network of conventional Wien oscillator. © 2011 IEEE.
    • Design, implementation and analysis of fully digital 1-D controllable multiscroll chaos

      Mansingka, Abhinav S.; Radwan, Ahmed G.; Salama, Khaled N. (ICM 2011 Proceeding, Institute of Electrical and Electronics Engineers (IEEE), 2011-12) [Conference Paper]
      This paper introduces the fully digital implementation of a 1-D multiscroll chaos generator based on a staircase nonlinearity in the 3rd-order jerk system using the Euler approximation. For the first time, digital design is exploited to provide real-time controllability of (i) number of scrolls, (ii) position in 1-D space, (iii) Euler step size and (iv) system parameter. The effect of variations in these fields on the maximum Lyapunov exponent (MLE) is analyzed. The system is implemented using Verilog HDL and synthesized on an Xilinx Virtex 4 FPGA, exhibiting area utilization less than 3.5% and high performance with experimentally verified throughput up to 3.33 Gbits/s. This fully digital system enables applications in modulation schemes and chaos-based cryptosystems without analog to digital conversion. © 2011 IEEE.
    • Fast global sequence alignment technique

      Bonny, Mohamed Talal; Salama, Khaled N. (2011 Conference Record of the Forty Fifth Asilomar Conference on Signals, Systems and Computers (ASILOMAR), Institute of Electrical and Electronics Engineers (IEEE), 2011-11) [Conference Paper]
      Bioinformatics database is growing exponentially in size. Processing these large amount of data may take hours of time even if super computers are used. One of the most important processing tool in Bioinformatics is sequence alignment. We introduce fast alignment algorithm, called 'Alignment By Scanning' (ABS), to provide an approximate alignment of two DNA sequences. We compare our algorithm with the wellknown sequence alignment algorithms, the 'GAP' (which is heuristic) and the 'Needleman-Wunsch' (which is optimal). The proposed algorithm achieves up to 51% enhancement in alignment score when it is compared with the GAP Algorithm. The evaluations are conducted using different lengths of DNA sequences. © 2011 IEEE.
    • ABS: Sequence alignment by scanning

      Bonny, Mohamed Talal; Salama, Khaled N. (2011 Annual International Conference of the IEEE Engineering in Medicine and Biology Society, Institute of Electrical and Electronics Engineers (IEEE), 2011-08) [Conference Paper]
      Sequence alignment is an essential tool in almost any computational biology research. It processes large database sequences and considered to be high consumers of computation time. Heuristic algorithms are used to get approximate but fast results. We introduce fast alignment algorithm, called Alignment By Scanning (ABS), to provide an approximate alignment of two DNA sequences. We compare our algorithm with the well-known alignment algorithms, the FASTA (which is heuristic) and the 'Needleman-Wunsch' (which is optimal). The proposed algorithm achieves up to 76% enhancement in alignment score when it is compared with the FASTA Algorithm. The evaluations are conducted using different lengths of DNA sequences. © 2011 IEEE.
    • Nonlinear analysis of ring oscillator circuits

      Ge, Xiaoqing; Arcak, Murat; Salama, Khaled N. (Proceedings of the 2010 American Control Conference, Institute of Electrical and Electronics Engineers (IEEE), 2010-06) [Conference Paper]
      Using nonlinear systems techniques, we analyze the stability properties and synchronization conditions for ring oscillator circuits, which are essential building blocks in digital systems. By making use of its cyclic structure, we investigate local and global stability properties of an n-stage ring oscillator. We present a sufficient condition for global asymptotic stability of the origin and obtain necessity if the ring oscillator consists of identical inverter elements. We then give a synchronization condition for identical interconnected ring oscillators.