| 1. |
- Kazim, Muhammad Irfan, et al.
(author)
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An Efficient Full-Wave Electromagnetic Analysis for Capacitive Body-Coupled Communication
- 2015
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In: International Journal of Antennas and Propagation. - : Hindawi Limited. - 1687-5869 .- 1687-5877. ; 2015, s. 15-
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Journal article (peer-reviewed)abstract
- Measured propagation loss for capacitive body-coupled communication (BCC) channel (1 MHz to 60 MHz) is limitedly available in the literature for distances longer than 50 cm. This is either because of experimental complexity to isolate the earth-ground or design complexity in realizing a reliable communication link to assess the performance limitations of capacitive BCC channel. Therefore, an alternate efficient full-wave electromagnetic (EM) simulation approach is presented to realistically analyze capacitive BCC, that is, the interaction of capacitive coupler, the human body, and the environment all together. The presented simulation approach is first evaluated for numerical/human body variation uncertainties and then validated with measurement results from literature, followed by the analysis of capacitive BCC channel for twenty different scenarios. The simulation results show that the vertical coupler configuration is less susceptible to physiological variations of underlying tissues compared to the horizontal coupler configuration. The propagation loss is less for arm positions when they are not touching the torso region irrespective of the communication distance. The propagation loss has also been explained for complex scenarios formed by the ground-plane and the material structures (metals or dielectrics) with the human body. The estimated propagation loss has been used to investigate the link-budget requirement for designing capacitive BCC system in CMOS sub-micron technologies.
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| 2. |
- Kazim, Muhammad Irfan, et al.
(author)
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Complex path impedance estimation and matching requirements for body-coupled communication
- 2015
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In: Circuit Theory and Design (ECCTD), 2015 European Conference on. - : IEEE. - 9781479998777 ; , s. 424-427
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Conference paper (peer-reviewed)abstract
- Capacitive body coupled communication (BCC) channel has been modeled as a two-port complex path impedance matrix [Z] which varies as a function of ten different body positions over the frequency range of 1 MHz to 60 MHz. A systematic numerical simulation methodology has been used to estimate [Z] parameters. The estimated complex path impedance [Z] is a symmetric matrix showing BCC channel is a reciprocal network of passive components for given coupler configuration, body positions and frequency range. The estimated complex path impedance has been utilized to determine either input impedance Zin or output impedance Zout to conjugately match to Zs at transmitter or Zl at receiver, respectively for maximum power transfer. It has been found that the resistive matching below 1000 O and inductive matching between 0.5 ï¿œH to 5 ï¿œH on any side of the two ports can meet the conjugate matching requirements for maximum power transfer for the given body positions and frequency range.
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| 3. |
- Kazim, Muhammad Irfan, et al.
(author)
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Realistic path loss estimation for capacitive body-coupled communication
- 2015
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In: Circuit Theory and Design (ECCTD), 2015 European Conference on. - : IEEE. - 9781479998777 ; , s. 173-176
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Conference paper (peer-reviewed)abstract
- Realistic estimation of path loss is vital for designing an effective capacitive body-coupled communication system. The estimation based on simplified analytical models, however, results in errors as they do not model capacitive couplers accurately and different body positions. The proposed efficient full-wave electromagnetic (EM) model takes into account the effect of capacitive coupler, electro-physiological properties of tissues in human body, different body positions and environment all together to realistically predict the path loss. A comparison of both approaches is made in this paper, showing the superior performance of the proposed model.
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| 4. |
- Khan, Muhammad Ahsan Iqbal, et al.
(author)
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An Experimental and Comparative Performance Evaluation of a Hybrid Photovoltaic-Thermoelectric System
- 2021
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In: Frontiers in Energy Research. - : FRONTIERS MEDIA SA. - 2296-598X. ; 9
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Journal article (peer-reviewed)abstract
- The majority of incident solar irradiance causes thermalization in photovoltaic (PV) cells, attenuating their efficiency. In order to use solar energy on a large scale and reduce carbon emissions, their efficiency must be enhanced. Effective thermal management can be utilized to generate additional electrical power while simultaneously improving photovoltaic efficiency. In this work, an experimental model of a hybrid photovoltaic-thermoelectric generation (PV-TEG) system is developed. Ten bismuth telluride-based thermoelectric modules are attached to the rear side of a 10 W polycrystalline silicon-based photovoltaic module in order to recover and transform waste thermal energy to usable electrical energy, ultimately cooling the PV cells. The experiment was then carried out for 10 days in Lahore, Pakistan, on both a simple PV module and a hybrid PV-TEG system. The findings revealed that a hybrid system has boosted PV module output power and conversion efficiency. The operating temperature of the PV module in the hybrid system is reduced by 5.5%, from 55 degrees C to 52 degrees C. Due to a drop in temperature and the addition of some recovered energy by thermoelectric modules, the total output power and conversion efficiency of the system increased. The hybrid system's cumulative output power increased by 19% from 8.78 to 10.84 W, compared to the simple PV system. Also, the efficiency of the hybrid PV-TEG system increased from 11.6 to 14%, which is an increase of 17% overall. The results of this research could provide consideration for designing commercial hybrid PV-TEG systems.
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| 5. |
- Harikumar, Prakash, et al.
(author)
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An Analog Receiver Front-End for Capacitive Body-Coupled Communication
- 2012
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In: NORCHIP, 2012. - : IEEE. - 9781467322225 - 9781467322218 ; , s. 1-4
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Conference paper (other academic/artistic)abstract
- This paper presents an analog receiver front-end design (AFE) for capacitive body-coupled digital baseband receiver. The most important theoretical aspects of human body electrical model in the perspective of capacitive body-coupled communication (BCC) have also been discussed and the constraints imposed by gain and input-referred noise on the receiver front-end are derived from digital communication theory. Three different AFE topologies have been designed in ST 40-nm CMOS technology node which is selected to enable easy integration in today's system-on-chip environments. Simulation results show that the best AFE topology consisting of a multi-stage AC-coupled preamplifier followed by a Schmitt trigger achieves 57.6 dB gain with an input referred noise PSD of 4.4 nV/√Hz at 6.8 mW.
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| 6. |
- Kazim, Muhammad Irfan, et al.
(author)
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Capacitive Body Coupled Communication : A Step Towards Reliable Short Range Wireless Technology
- 2015
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Other publication (other academic/artistic)abstract
- The paradigm of computation is currently changing from desktop computing towards ubiquitous computing by interfacing ambulatory devices with mobile phones/platforms. For an efficient implementation, ultra short range wireless network technologies, such as the body area network (BAN), are needed which could avoid the saturation of carrier frequencies, low power dissipation, and the electromagnetic interference. In this work, body coupled communication (BCC) based on capacitive reactive field has been outlined as an important extension of BAN. It has been experimentally demonstrated as an alternative to traditional short range wireless communication based on radio frequency (RF) technologies. The concept of signal transmission through the capacitive BCC channel is explained using a lumped circuit model which is further supported by electromagnetic (EM) simulations. There are three different communication architectures which have been experimentally demonstrated using discrete electronic components for capacitive BCC channel for data rates between 1 kbps to 100 kbps. The architectures are based on digital baseband communication and passband communication with LC resonant mode driver. The best architecture is based on passband communication which has been demonstrated for reliable ECG measurement in the context of preventive healthcare.
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| 7. |
- Kazim, Muhammad Irfan, et al.
(author)
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Design of a Sub-mW Front-End Amplifier for Capacitive BCC Receiver in 65 nm CMOS
- 2016
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In: Proceedings of 2016 13th International Bhurban Conference on Applied Sciences and Technology (IBCAST). - : Institute of Electrical and Electronics Engineers (IEEE). - 9781467391269 - 9781467391276 - 9781467391252 ; , s. 607-610
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Conference paper (peer-reviewed)abstract
- A low power front-end fully differential operational transconductance amplifier (OTA) has been designed in 65 nm CMOS technology which is suitable to receive low data rates upto 300 kbps for capacitive body coupled communication (BCC) channel. The current shunt current mirror OTA topology has been utilized in open loop configuration in the context of digital baseband architecture on the receiver side. The simulated resuts show that OTA achieves unity gain bandwidth (UGBW) of 200 MHz, dc gain of 40 dB, phase margin of 45 degree and rms integrated noise of 130 μV between 10 kHz to 150 MHz for 1.5 pF load capacitance and power consumption of approximately 250 μW. The OTA achieves high CMRR and PSRR (due to positive supply) of more than 120 dB at 100 Hz.
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| 8. |
- Kazim, Muhammad Irfan, et al.
(author)
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Printed Electrodes with Memory Labels Embracing Body Coupled Communication : An Alternate M2M Communication Paradigm for Internet of Things
- 2015
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Other publication (other academic/artistic)abstract
- A cost-effective concept of silicon-printed hybrid memory label for capacitive body coupled communication (BCC) is discussed in this paperin the context of internet of things (IoT). The strength of a hybrid approach is deliberated after careful review of organic thin film transistors (OTFTs) performance in the existing printed technologies. Further, the performance of battery operated baseband and passband communication architectures have experimentally been demonstrated for an alternate, short range, wireless, machine-to-machine (M2M) communication paradigm for smart phones platform, the capacitive BCC channel. The operating frequency range is from 100 kHz to 10 MHz for different body positions and printed electrodes configuration/sizes in conjunction with different output drivers. The transmission/reception of signals to the smart phone has been carried out through an SPI and Bluetooth interface to ensure that isolated earth ground conditions were guaranteed for capacitive BCC channel. The BCC passband communication architecture achieves 1 kbps while the digital baseband architecture achieves 100 kbps data rate for 10−2 packet error rate (PER) in the given experimental setup.
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| 9. |
- Kazim, Muhammad Irfan, 1979-
(author)
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Variation-Aware System Design Simulation Methodology for Capacitive BCC Transceivers
- 2015
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Doctoral thesis (other academic/artistic)abstract
- Capacitive body coupled communication (BCC), frequency range 500 kHz to 15 MHz, is considered an emerging alternate short range wireless technology which can meet the stringent low power consumption (< 1 mW) and low data rate (< 100 kbps) requirements for the next generation of connected devices for applications like internet-of-things (IoT) and wireless sensor network (WSN). But a reliable solution for this mode of communication covering all possible body positions and maximum communication distances around the human body could not be presented so far, despite its inception around 20 years back in 1995. The uncertainties/errors associated with experimental measurement setup create ambiguity about the measured propagation loss or transmission errors. The reason is the usage of either earth grounded lab instruments or the direct coupling of earth ground with transmitter/receiver or the analog front end cut-off frequency limitations in a few MHz region or the balun to provide isolation or the measurements on simplified homogeneous biological phantoms. Another source of ambiguity in the experimental measurements is attributed to the natural variations in human tissue electrophysiological properties from person to person which are also affected by physical factors like age, gender, number of cells at different body locations and humidity. The analytical models presented in the literature are also oversimplified which do not predict the true propagation loss for capacitive BCC channel.An attempt is being made to understand and demonstrate, qualitatively and quantitatively, the physical phenomenon of signal transmission and propagation characteristics e.g., path loss in complex scenarios for capacitive BCC channel by both the experimental observations/measurements and simulation models in this PhD dissertation. An alternate system design simulation methodology has been proposed which estimates the realistic path loss even for longer communication distances > 50 cm for capacitive BCC channel. The proposed simulation methodology allows to vary human tissue dielectric/thickness properties and easily integrates with the circuit simulators as the output is in the form of S-parameters. The advantage is that the capacitive BCC channel characteristics e.g., signal attenuation as a function of different physical factors could be readily simulated at the circuit level to choose appropriate circuit topology and define suitable system specifications. This simulation methodology is based on full-wave electromagnetic analysis and 3D modeling of human body and environment using their conductivity, permittivity, and tangent loss profile to estimate the realistic propagation loss or path loss due to their combined interaction with the electrode coupler for capacitive BCC channel. This methodology estimates the complex path impedance from transmitter to receiver which is important to determine the matching requirements for maximum power transfer. The simulation methodology also contributes towards better understanding of signal propagation through physical channel under the influence of different electrode coupler configurations. The simulation methodology allows to define error bounds for variations in propagation loss due to both numeric uncertainties (boundary conditions, mesh cells) and human body variation uncertainties (dielectric properties, dielectric thicknesses) for varying communication distances and coupler configuration/sizes.Besides proposing the simulation methodology, the digital baseband and passband communication architectures using discrete electronics components have been experimentally demonstrated in the context of IoT application through capacitive BCC channel for data rates between 1 kbps to 100 kbps under isolated earth ground conditions. The experimental results/observations are supported by the simulation results for different scenarios of capacitive BCC channel.The experimental and simulation results help in defining suitable system specifications for monolithic integrated circuit design of analog front end (AFE) blocks for capacitive BCC transmitter/receiver in deep submicron CMOS technologies.
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