Moaaz Ahmed

Hamad bin Khalifa University | HBKU · College of Science and Engineering

Visible light communication (VLC) transceivers suffer from optical interference and ambient light saturation, which severely affect the reception of optical signals. In this paper, we discuss various techniques for the suppression of ambient light in electronic, optical, communication and wavelength domains with focus on VLC systems for vehicular c...

This article presents a compact blood flow measurement system exploiting the Doppler effect and photocurrent sensing technique for wearable health monitoring. Specifically, it helps the patients suffering from peripheral artery disease (PAD) to monitor the blood flow continuously without involving a physician or medical expert. The system prototype...

Coral reefs represent one of the most biodiverse marine ecosystems on our planet. These consist of colonies of very small sea animals belonging to the phylum named Cnidaria, and of more complex, yet not so well-known microbial communities. Despite the fact that they occupy only a tiny portion of the oceans' surface, coral reefs are swarming with li...

Visible light communication has emerged as a promising complementary technology to enable communication between vehicles and traffic infrastructure. However, the visible light transceivers suffer from optical interference and ambient light saturation which severely affect the reception of the optical signal. In this paper, we present an overview of...

Optoelectronic devices are advancing from existing rigid configurations to deformable configurations. These developing devices need transparent electrodes (TEs) having high mechanical deformability while preserving the high electrical conductivity and optical transparency. In agreement with these requirements, vacuum-fabricated conventional TEs bas...

This work presents an interesting approach towards rapid manufacturing of multi-stripes based deflection sensors developed through printing technologies. The deflection sensor is made of multiple small-scale strain sensing stripes sandwiched between consecutive conducting stripes. The drop-on-demand inkjet printing is used to pattern silver (Ag) na...

We propose systems. a passive detection and tracking methodology for Cam-Com receivers in intelligent transport systems. The implemented architecture maximizes the data rate and can maintain a BER of 1.9 × 10−4 while passively detecting and tracking the moving transmitter undergoing worst-case road vibration of 30.6 mm/s. The proposed methodology i...

One of the main challenges in establishing a robust visible light communication (VLC) link is to prevent optical interference produced by other light sources from corrupting the signal. Previous solutions aiming to solve this issue assume that the signal and optical noise are present in nonoverlapping frequency bands. Our design incorporates an inn...

MEMS flow sensors are becoming increasingly popular in a wide range of applications, such as drug delivery control, medical ventilators, combustion engines, and industrial process control. The scope of our project is to build a very compact and low-power flow sensor for emerging IoT applications and to replace bulky mass flow controllers. These are...

Visible light communication (VLC) is gaining immense popularity for its inherent energy-efficient and freely available wide unlicensed spectrum in a range of applications that include indoor positioning, medical and navigational equipments and smart vehicular networks. In this paper, we present a current mirroring integration (CMI) based VLC receiv...

This article presents a 3-D integrated molybdenum (Mo) thermoresistive microcalorimetric flow sensor in a 0.18-μm CMOS MEMS technology. The sensor consists of a MEMS structure which is fabricated inside a sealed microchannel and a constant temperature control circuit implemented on the CMOS wafer. The MEMS structure and the CMOS circuit are 3-D int...

Leveraging More-than-Moore technology, we demonstrate an integrated CMOS MEMS flow sensor via a very compact system on chip (SoC) that can sense the bidirectional N <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> gas flow. Our SoC features a very low-noise instrumentation amplifier that is impl...

In this work, we present a systematic design methodology which explores the design space (for ultralow noise chopper instrumentation amplifiers) in all regions of MOSFET operation. Our work is the first of its kind to extend the gm=ID based design methodology for precision instrumentation amplifiers by taking into account a comprehensive set of par...

Incremental analog to digital converters (IADCs) are aimed at converting low frequency signals with high accuracy. The operational transconductance amplifiers (OTAs) used to implement the integrators are the dominant source of power consumption, since they must settle to a desired accuracy within a given clock period, by driving a capacitive load....

An integrated low-cost micro BTU (µBTU) sensor system, including a thermoresistive micro calorimetric flow (TMCF) sensor and a resistance temperature detector (RTD), is reported for the first time using a proprietary InvenSense CMOS MEMS technology integrated with a digital signal processing (DSP) unit. The proposed BTU sensor features an integrate...

This paper presents an ultra-low-power low-noise capacitively-coupled chopper instrumentation amplifier (CCIA). A current-reuse telescopic topology in the first stage along with a recycling folded-cascode topology in the second stage consumes net bias current of 26�A with enhanced efficiency and achieves an input-referred noise power-spectral-densi...

We present an integrated CMOS MEMS flow sensor which demonstrates a very compact system on chip (SoC) that can sense N2 gas flow ranging from 0 to 26m/s (0-50sccm). Implemented in the proprietary InvenSense AlN process, our SoC features a very low-power Current Feedback Instrumentation Amplifier (CFIA) as a front-end readout circuit for a microcalo...

In this paper, we presented a wafer-level encapsulated Thermoresistive Micro Calorimetric Flow (TMCF) sensor with the integrated packaging by using the proprietary InvenSense CMOS MEMS technology. For the nitrogen gas flow from-26m/s to 26m/s, the pulsed operated TMCF sensor (device size = 3.4mm 2) under the Constant Temperature Difference (CTD) mo...

A nested chopped current-feedback instrumentation amplifier (CFIA) designed for micro-fluidic applications is reported in this work. The proposed CFIA is chopped at 50kHz to bring input-referred offset below 12uV and flicker-noise corner around 100mHz. In order to further suppress the residue offset to nV-level, the CFIA is again chopped with a slo...

A nested chopped current-feedback instrumentation amplifier (CFIA) designed for micro-fluidic applications is reported in this work. The proposed CFIA is chopped at 50kHz to bring input-referred offset below 12uV and flicker-noise corner around 100mHz. In order to further suppress the residue offset to nV-level, the CFIA is again chopped with a slo...

A 14-bit SHA-less pipeline ADC based on 2.5-bit per stage architecture is proposed. Implemented in TSMC 0.18u�m CMOS process, the proposed ADC achieves an ENOB of 11.34-bits and consumes 41 mW power at 70 MS/s thereby achieving an FOM of 226fJ/conversion-step which compares favorably with state-of-the-art work. The low-power consumption is attribut...

A current-feedback instrumentation amplifier (CFIA) for precision bridge-readout intended for MEMs flow sensor is presented. The proposed CFIA is chopped to bring input-referred offset below 12�uV and flicker-noise corner around 2mHz. Implemented in chartered 0.18�um CMOS process, the CFIA draws 250�uA supply current and achieves a competitive nois...

An improved recycling folded cascode operational transconductance amplifier with gain boosting and enhanced phase-margin is proposed. Among four variants of folded cascode amplifiers that have been implemented in TSMC 0.18µm CMOS process under same power and area constraints, the proposed amplifier achieves the lowest settling error of less than 0....

A very low power optical wireless receiver for use in low rate, short range applications, in general, and for use in retinal prosthesis application, in particular, is proposed. Conventional optical wireless receivers are based on transimpedance amplifier and consume large static power which is not suitable for low power biomedical applications. The...

This paper proposes six different CMOS-based temperature sensor topologies by exploiting temperature dependence of MOSFET's threshold voltage VT, the carrier's mobility μ and the resistivity of n-well resistors. The proposed temperature sensors are designed for a wide temperature range of −100 °C to +120 °C and exhibit resolutions in the range of 0...

This paper presents a low-noise and high dynamic-range CMOS readout-IC (ROIC) for a 64 × 64 array of opto-electrical sensors. The readout chain comprises a pixel preamplifier array, correlated-double-sampling based switched-capacitor gain blocks, class-AB output buffer for driving off-chip loads and a 12-bit pipeline ADC for on-chip digitization. T...

This paper presents a low-noise and high dynamic-range CMOS readout-IC (ROIC) for a 64 9 64 array of opto-electrical sensors. The readout chain com-prises a pixel preamplifier array, correlated-double-sam-pling based switched-capacitor gain blocks, class-AB output buffer for driving off-chip loads and a 12-bit pipeline ADC for on-chip digitization....

Hash based security systems using a one way hash function are widely used in the network security. Design of such system revolves around the selection of proper function. An ideal hash function is the one that will never cause a collision. Although separate chaining and other techniques can be successfully applied for collision resolution, it is st...