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Disposable, Paper-Based, Inkjet-Printed Humidity and H2S Gas Sensor

posted Dec 6, 2016, 3:41 AM by Khaled salama

We continue working on H2S sensors in collaboration with prof. Atif Shamim and Prof. Hammad Cheema. We present an inkjet-printed, fully passive sensor capable of either humidity or gas sensing. The sensor is composed of an interdigitated electrode, a customized printable gas sensitive ink and a specialized dipole antenna for wireless sensing. The interdigitated electrode printed on
a paper substrate provides the base conductivity that varies during the sensing process.  A fast response time of 3 min is achieved at room temperature for a H2S concentration of 10 ppm at a relative humidity (RH) of 45%. The passive wireless sensing is enabled through an antenna in which the inner loop takes care of conductivity changes in the 4–5 GHz band, whereas the outer-dipole arm
is used for chipless identification in the 2–3 GHz band.
More details can be found at:
 Abdul Quddious , Munawar M. Khan , Farooq A. Tahir, Shuai Yang, Atif Shamim, Khaled N. Salama, Hammad M. Cheema, Disposable, Paper Based and Inkjet-Printed Humidity and H2S Gas Sensor for Passive Sensing ApplicationsSensors 2016, 16, 2073; doi:10.3390/s16122073 


Dr Hesham Omran breaks the world's capacitance to digital converters (CDCs) FoM record

posted Nov 18, 2016, 12:56 PM by Khaled salama   [ updated Nov 18, 2016, 3:58 PM ]

 A 12 − bit energy-efficient capacitive sensor interface circuit that fully relies on capacitance-domain successive approximation (SAR) technique is demonstrated based on a chain of cascode inverter-based amplifiers with near-threshold biasing. Experimental results show an energy efficiency figure-of-merit (FoM) of 33 f J/Step which outperforms the state-of-the-art. The CDC output is insensitive to analog references; thus, a very low temperature sensitivity of 2.3 ppm/◦C is achieved without the need for calibration. The work has been accepted at IEEE transactions on circuits and systems.
H. Omran, Abdulaziz Alhoshany, H. Alahmadi, and K. N. Salama, A 33fJ/Step SAR Capacitance-to-Digital Converter Using a Chain of Inverter-Based AmplifiersIEEE Transactions on Circuits and Systems I, 2016 10.1109/TCSI.2016.2608905

Its worth mentioning that a differential version of the work has been presented at the prestigious VLSI symposium with almost the same FoM due the use of Quasi-dynamic operation to maintain the energy efficiency for a scalable sample rate
H. Omran, A. Alhoshany, H. Alahmadi , and K. N. Salama, “A 35fJ/Step Differential Successive Approximation Capacitive Sensor Readout Circuit with Quasi-Dynamic Operation,” Symposia on VLSI Technology and Circuits, 2016.

This work builds on our earlier work:
  1. Hesham Omran, Muhammad Arsalan and Khaled N. Salama, An Integrated Energy-Efficient Capacitive Sensor Digital Interface Circuit, Sensors and Actuators A: Physical, Volume 216, Pages 43–51, 2014
  2. H. Omran, M. Arsalan, and K. N. Salama, “A robust parasitic-insensitive successive approximation capacitance-to-digital converter,” IEEE Custom Integrated Circuits Conference (CICC), 2014.
  3.  H. Omran, H. Alahmadi, and K. N. Salama, “Matching properties of femtofarad and sub-femtofarad MOM capacitors,” IEEE Transactions on Circuits and Systems I, 2016 
  4. Hesham Omran, Rami T. ElAfandy, Muhammad Arsalan, and Khaled N. Salama, Direct Mismatch Characterization of femto-Farad Capacitors, IEEE transactions on circuits and systems II, vol 63, no 2, pp. 151-155,  2016. (DOI:10.1109/TCSII.2015.2468919)
  5. Abdulaziz Alhoshany, Hesham Omran, Khaled N. Salama, "A 45.8fJ/Step, Energy-Efficient, Differential SAR Capacitance-to-Digital Converter for Capacitive Pressure Sensing", Sensors & Actuators: A. Physical, Vol 245, Pages 10–18, 2016

Mahmoud is now Dr Ouda :)

posted Nov 3, 2016, 9:06 PM by Khaled salama   [ updated Dec 19, 2016, 10:26 PM ]

Dr Mahmoud Ouda just defended his PhD which was highly received. Mahmoud worked on wireless energy harvesting from ambient RF signals. The dissertation is unique in developing an integrated RF-DC converter with on-chip antenna for lowering costs—in essence eliminating the cost of fabricating a different antenna.  Another unique aspect of this thesis is the RF harvester’s integration with a wireless powered implantable sensor. Such sensors will become ubiquitous for medical applications, with their numbers reaching in the trillions. The need to power these sensors wirelessly eliminates batteries and makes the sensors maintenance free.  Also, the achieved efficiencies of 65% at 433MHz with an input power of -15dBm is well in line with some of the best achieved efficiencies. Further, the developed RF-to-DC power converter, operating at 5.2GHz and incorporating adaptive self-biasing, is certainly unique. Even more, the peak efficiency of 90% is quite impressive. That is, this work carried out RF-to-DC harvesting at 400MHz and at 5.2GHz.  This work was conducted in collaboration with Prof. Waleed Khalil, Thh ohio state university.  The details are outlined in his thesis  "Wide-Range Highly-Efficient Wireless Power Receivers for Biomedical Sensors". 




Prof. John Volakis, the director of Electroscience lab, The ohio state university commented that " Mahmoud has done an impressive amount of work. His focus has certainly been on the integration of RF-to-DC wireless power harvester with medical sensors. Altogether, Mr. Ouda has published 5 journal papers in well-read and followed journals. This is impressive, and demonstrates the strong contributions of this dissertation."







His work resulted in following publications:
  1. M. Ouda, W. Khalil and K.N. Salama, "Self-Biased Differential Rectifier with Enhanced Dynamic Range for Wireless Powering" IEEE Transactions on Circuits and Systems II: Express Briefs, 2016 (accepted)
  2.  M. Ouda, W. Khalil and K.N. Salama, "Wide-Range Adaptive RF-to-DC Power Converter for UHF RFIDs," IEEE Microwave and Wireless Components Letters, 2016 10.1109/LMWC.2016.2586077
  3. M. Ouda, L. Marnat, A. Shamim, K N Salama, 5.2-GHz RF Power Harvesting Module in 0.18 μm CMOS for Biomedical Implantable Sensors, IEEE Transactions on Microwave Theory and Techniques, vol 61, n 5, pp 2177-2184,  2013
  4.  L. Marnat, M. Ouda, M. Arsalan, K. Salama, A. Shamim, "On-chip implantable antennas for wireless power and data transfer in a glaucoma monitoring SoC", IEEE Antennas and Wireless Propagation Letters (AWPL), vol 11, pp 1671-1674, 2012 
  5. A. M. Elshurafa, A.G. Radwan, P. H. Ho, M. Ouda and K. N. Salama "Low Voltage Puzzle-Like Fractal  MEMS Variable Capacitors Suppressing Pull-in" IET micro and nano letters, vol. 7, no. 9, pp. 965-969, 2012. 
  6. M. Arsalan, M. H. Ouda, L. Marnat, A. Shamim, K. N. Salama," Implantable Intraocular Pressure Monitoring Systems: Design Considerations",Microwave Workshop Series on RF and Wireless Technologies for Biomedical and Healthcare Applications (IMWS-BIO), 2013 IEEE MTT-S International
  7. M. Arsalan, M. Ouda, L. Marnat, A. Shamim and K N Salama,  A 5.2GHz, 0.5mW RF Powered Wireless Sensor with Dual On-Chip Antennas for Implantable Intraocular Pressure MonitoringIEEE MTT-S International Microwave Symposium Digest (IMS), 2013

Abdulaziz got his first author Sensors and Actuators: A

posted Nov 3, 2016, 7:35 PM by Khaled salama   [ updated Nov 3, 2016, 7:58 PM ]

Abdulaziz demnostrates the lowest reported Figure of Merit of 45.8fJ/step capacitance to Digital converter. This CDC meets extremely low power requirements by using an operational transconductance amplifier (OTA) that is based on a current-starved inverter. It uses a charge-redistribution DAC that involves coarse-fine architecture.  The prototype CDC was fabricated using a standard 180 nm CMOS technology. The 12-bit CDC has a measurement time of 42.5 μs, covers a wide range of capacitance of 16.14 pF with a 4.5 fF absolute resolution and consumes 3.54 μW and 0.29 μW from analog and digital supplies, respectively. For more details check


Abdulaziz Alhoshany, Hesham Omran, Khaled N. Salama, "A 45.8fJ/Step, Energy-Efficient, Differential SAR Capacitance-to-Digital Converter for Capacitive Pressure Sensing", Sensors & Actuators: A. Physical, Vol 245, Pages 10–18, 2016



This work builds on our earlier work:
  1. Hesham Omran, Muhammad Arsalan and Khaled N. Salama, An Integrated Energy-Efficient Capacitive Sensor Digital Interface Circuit, Sensors and Actuators A: Physical, Volume 216, Pages 43–51, 2014
  2. H. Omran, M. Arsalan, and K. N. Salama, “A robust parasitic-insensitive successive approximation capacitance-to-digital converter,” IEEE Custom Integrated Circuits Conference (CICC), 2014.
  3.  H. Omran, H. Alahmadi, and K. N. Salama, “Matching properties of femtofarad and sub-femtofarad MOM capacitors,” IEEE Transactions on Circuits and Systems I, 2016 
  4. Hesham Omran, Rami T. ElAfandy, Muhammad Arsalan, and Khaled N. Salama, Direct Mismatch Characterization of femto-Farad Capacitors, IEEE transactions on circuits and systems II, vol 63, no 2, pp. 151-155,  2016. (DOI:10.1109/TCSII.2015.2468919)
Follow up work:
  1. H. Omran, A. Alhoshany, H. Alahmadi , and K. N. Salama, “A 35fJ/Step Differential Successive Approximation Capacitive Sensor Readout Circuit with Quasi-Dynamic Operation,” Symposia on VLSI Technology and Circuits, 2016.
  2. H. Omran, Abdulaziz Alhoshany, H. Alahmadi, and K. N. Salama, A 33fJ/Step SAR Capacitance-to-Digital Converter Using a Chain of Inverter-Based Amplifiers" IEEE Transactions on Circuits and Systems I, 2016

Dr Omar Yassine demonstrates a remarkable 100ppb detection of hydrogen sulfide (H2S)

posted Nov 3, 2016, 7:11 PM by Khaled salama   [ updated Dec 1, 2016, 9:14 AM ]

We continue our strong Collaboration with Prof. M. Eddaoudi on gas sensing.  we report the fabrication of an advanced sensor for the detection of hydrogen sulfide (H2S) at room temperature, using thin films of rare-earth metal (RE)-based metal–organic framework (MOF) with underlying fcu topology.  The sensor showed a remarkable detection sensitivity for H2S at concentrations down to 100 ppb, with the lower detection limit around 5 ppb. The fum-fcu-MOF sensor exhibits a highly desirable detection selectivity towards H2S vs. CH4, NO2, H2, and C7H8 as well as an outstanding H2S sensing stability as compared to other reported MOFs. More details can be found at:


Omar Yassine, Osama Shekhah, Ayalew H. Assen, Youssef Belmabkhout, Khaled N. Salama and Mohamed Eddaoudi "H2S Sensors: Fumarate-Based fcu-MOF Thin Film Grown on a Capacitive Interdigitated Electrode" , Angew. Chem. Int. Ed.. doi:10.1002/anie.201608780

This builds on our earlier work with Eddaoudi's group:
  1. Sapsanis, C.; Omran, H.; Chernikova, V.; Shekhah, O.; Belmabkhout, Y.; Buttner, U.; Eddaoudi, M.; Salama, K.N. Insights on Capacitive Interdigitated Electrodes Coated with MOF Thin Films: Humidity and VOCs Sensing as a Case Study.Sensors15, 18153-18166, 2015.

Synaptic Versus Neuronal Stochasticity explained

posted Nov 3, 2016, 7:05 PM by Khaled salama   [ updated Nov 3, 2016, 7:18 PM ]

In yet another very interesting work, PhD student Rawan Naous explores stochasticity in the cortex based on either the synaptic or neuronal components. The hardware emulation of these stochastic neural networks are currently being extensively studied using resistive memories or memristors.  Aside from the size and area perspective, the impact on the system performance, in terms of accuracy, recognition rates, and learning, among these two approaches and where the memristor would fall into place are the main comparison points considered.  For more details check:

Rawan Naous, Maruan AlShedivat, Emre Neftci, Gert Cauwenberghs and Khaled Nabil Salama, " Memristor-based neural networks: Synaptic versus neuronal stochasticity"AIP Advances 6, 111304 (2016); http://dx.doi.org/10.1063/1.4967352

This expands our earlier work:
  1. Rawan Naous, Maruan Al-Shedivat, and Khaled Nabil Salama, Stochasticity Modeling in MemristorsIEEE Transactions on Nanotechnology (TNANO), vol. 15, no. 1, pp. 15-28, 2016 DOI:10.1109/TNANO.2015.2493960
  2.  Rawan Naous., Maruan Al-Shedivat, Emri Neftci, Gert Cauwenberghs and Khaled Nabil Salama "Stochastic Synaptic Plasticity with Memristor Crossbar Arrays", IEEE Int'l Symposium on Circuits & Systems (ISCAS), to be held in Montreal, Canada, 2016
  3. Maruan Al-Shedivat, Rawan Naous,Gert Cauwenberghs, and Khaled Nabil Salama, Memristors Empower Spiking Neurons with Stochasticity, IEEE Journal of Emerging technologies in circuits and systems, VOL. 5, NO. 2, 242-253, JUNE 2015
  4. Maruan Al-Shedivat, Rawan Naous., Emre Neftciy, Gert Cauwenberghsy and Khaled N. Salama., "Inherently Stochastic Spiking Neurons for Probabilistic Neural Computation', 7th International IEEE EMBS Neural Engineering Conference (NER'15), Montpellier, France on April 22-24, 2015.

Congrats Rawan!

Compatibility analysis of 3D printer resin for biological applications @MNL

posted Aug 31, 2016, 1:39 PM by Khaled salama

The salient features of microfluidics such as reduced cost, handling small sample and reagent volumes and less time required to fabricate the devices has inspired the present study.  we report the incompatibility of 3D printer resins in their native form and the method to improve their compatibility to many biological processes via surface modification.  Recently 3D printed microfluidics have contributed substantially regarding cost cutting to the fabrication of advanced lab on-chip devices to biomedical field. The compatibility of the material to build microfluidic devices was evaluated in three different ways (1) determining if the UV cured resin inhibits the polymerase chain reaction (PCR) i.e., testing devices for PCR compatibility and (2) observing agglutination complex formed on the surface of the UV cured resin when anti-CRP antibodies and Creactive protein (CRP) proteins were allowed to agglutinate (3) by culturing human embryonic kidney cell line (HEK) cells and testing for its attachment and viability. This study finds importance in building Lab-on-chip/Micro Total analysis systems (µTAS) and organ-on-chip devices.  

This work is a collaboration with prof. Niveen Khashab. This work was first presented at NEMS 2016 and was invited for a special issue  at the IET Micro and Nano letter. More details can be found at 

Shilpa Sivashankar, Sumeyra Agambayev, kholod alamoudi,  Ulrich Buttner,Niveen Khashab, and Khaled Nabil Salama Compatibility analysis of 3D printer resin for biological applications, micro and nano letters, 2016

Shilpa Sivashankar, Sumeyra Agambayev, Ulrich Buttner, Khaled Nabil Salama, Characterization of Solid UV Curable 3D Printer Resins for Biological Applications, NEMS2016


Mahmoud demonstrates a self Biased energy harvesting module @TCASII

posted Aug 31, 2016, 1:28 PM by Khaled salama

WIRELESS power transfer (WPT) applications range from powering battery-less wireless sensors, RFIDs, and implantable devices, to  the higher scale of space-based solar cells and wirelessly charged electric vehicles. Among this myriad of battery-less devices, the wireless power receiver is considered the linchpin for any given WPT system. A prototype is designed for UHF 433MHz RF power-harvesting applications and is implemented using 0.18µm CMOS technology. It demonstrates an improvement of more than 40% in the rectifier power conversion efficiency (PCE) and an input power range extension of more than 50% relative to the conventional  cross coupled rectifier. A sensitivity of -15.2dBm (30µW) input power for 1V output voltage and a peak power-conversion efficiency of 65% are achieved for a 50kΩ load.

The work is in collaboration with Prof. Khalil, of the Electroscience lab, Ohio State Univeristy and is presented in details at IEEE Transactions on Circuits and Systems II: Express Briefs

IEEE Transactions on Circuits and Systems II: Express Briefs, 2016 

Congrats Mahmoud!

2016 Shanghai Ranking (aka ARWU) is out

posted Aug 15, 2016, 1:10 AM by Khaled salama

Kaust is progressing in a very good way.
 
Check 2016 ranking

http://www.shanghairanking.com/World-University-Rankings/King-Abdullah-University-of-Science-and-Technology.html

Rawan publishes yet another paper on memristor crossbars :)

posted Aug 7, 2016, 1:23 AM by Khaled salama   [ updated Aug 14, 2016, 6:02 AM ]

Our work on the analysis and statistical distribution of memristor crossbar memories is accepted at the international journal of unconventional computing. This adds to our list of papers on the problem of sneak path

In this work, a novel approach is adopted to accommodate the sneak path and counter its effect on the memory reading. In contrast to the alternative techniques, where spatial and temporal solutions are applied to alleviate the distortion limitation and set a dynamic threshold, statistical measures benefit from the prior read data within the array. It builds upon the noise reduction and estimation principles, mainly borrowing concepts of coding and detection theory to enhance the access time and accuracy of the reading process.  More details can be found at following publications:
 
  1. Rawan Naous, Mohammed Zidan,  Ahmed Sultan, and Khaled Salama "Statistical Analysis for Memristor Crossbar MemoriesInternational Journal of Unconventional Computing, vol 12, n 4, pp 265-280, 2016 
  2. Rawan Naous, Mohammed Zidan,  Ahmed Sultan, and Khaled Salama, Pilot Assisted Readout for Passive Memristor CrossbarsMicroelectronics journal, Vol 54,  pp 48–58, 2016
  3. Rawan Naous., Mohammed Affan Zidan, Ahmed Sultan., and Khaled Nabil Salama., "Channel Equalization Techniques for Non-volatile Memristor Memories" IEEE 50th Annual Conference on Information Sciences and Systems, pp. 111-116, 2016
  4. R. Naous, M. Affan Zidan, A. Sultan, and K. N. Salama, “Memristor Based Crossbar Memory Array Sneak Path Estimation,” 4th Memristorand Memristive Symposium, Notre Dame, USA 

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