Sharjeel Afridi - Academia.edu (original) (raw)
Papers by Sharjeel Afridi
Real‐time low cost compact liquid‐water binary mixture monitoring sensor
Microwave and Optical Technology Letters, Jun 29, 2020
This work proposes a novel method for detecting the concentration of water present in liquid‐wate... more This work proposes a novel method for detecting the concentration of water present in liquid‐water binary mixture in real time with a low cost, portable measurement setup. The sensing element in the proposed system is a two‐port microstrip bandstop resonator based on coupled line open‐ended quarter wavelength section. Voltage control oscillator and power detector ICs are used to generate and detect the microwave power at specific bandstop frequency. Water concentrations in commercially available liquids are monitored both in batch and continuous mode of operation using separate 3D printed liquid containing fixtures attached to the open end of the microstrip line. The measured results successfully validate the design theory.
IEEE Access
This work presents a design technique to implement miniaturized cross-coupled bandpass filters in... more This work presents a design technique to implement miniaturized cross-coupled bandpass filters in inline physical configurations based on triple-mode resonators. Triple-mode resonances are obtained by using integrated coaxial-waveguide cavity resonators. They consist of two coaxial conducting posts placed in the sidewalls of a rectangular waveguide cavity. In the proposed triplet, a transmission zero (TZ) can be positioned at any of the two sides of the passband by simply locating the coaxial posts either on the same wall or on opposite walls of the rectangular waveguide cavity. Coaxial-to-waveguide mode coupling is implemented by means of coupling screws, which adds flexibility in terms of tuning easiness. Three 9.9-GHz proof-of-concept prototypes corresponding to third-and sixth-order integrated coaxial-waveguide bandpass filters are designed at the electromagnetic-simulation level. Furthermore, the triplet with a TZ below the passband is manufactured and characterized to experimentally validate the engineered 3-D RF filter principle and its underlying design theory. INDEX TERMS 3-D filter, bandpass filter, coaxial filter, inline filter, microwave filter, transmission zero (TZ), waveguide filter.
Ceramic Waveguide Filters with Improved Stop band Rejection and Transmission Zeros
2023 4th International Conference on Computing, Mathematics and Engineering Technologies (iCoMET)
Experiments with Neural Networks Training Algorithms for DDoS attacks Detection
SINDH UNIVERSITY RESEARCH JOURNAL -SCIENCE SERIES, 2019
Attacks on servers to bring their services down is growing rapidly. There are several possible me... more Attacks on servers to bring their services down is growing rapidly. There are several possible methods through which attackers can attack a server. Distributed denials of service (DDoS) attacks are one of these attacks types in computing environments. In this paper, we discuss the possible ways of DDoS attacks detection using artificial neural network based techniques. Here a feed forward neural network is designed to detect DDoS attacks in a network based environment. Performance of feed forward neural network is analyzed by applying three different training algorithms. These algorithms are (1) Scaled Conjugate Gradient (2) Bayesian Regularization and (3) Gradient Descent. Results show that Bayesian Regularization algorithm is better among these three training algorithms and it has less number of misclassifications.
Comparative Analysis of MIMO OFDM System Using Different Fading Techniques
SINDH UNIVERSITY RESEARCH JOURNAL -SCIENCE SERIES, 2019
The MIMO technology utilizes different antennas at each terminal of a wireless link and greatly i... more The MIMO technology utilizes different antennas at each terminal of a wireless link and greatly improves the link reliability and spectral efficiency of future wireless communication systems. This technology integrated with Orthogonal Frequency Division Multiplexing (OFDM), which is particularly proving a propitious entrant for upcoming next generation wireless systems including both mobile and fixed systems. It provides an attractive air-interface solution for next-generation wireless/cellular systems. In this paper Waterfilling algorithm has been used to optimize transmit power for maximizing the capacity. The Waterfilling algorithm successfully solved the problem of power allocation for MIMO-OFDM wireless network and adaptively allocate power to minimize BER performance and increasing the capacity in order to maintain the QoS requirements for a network. The proposed work is investigated by using Matlab tool.
Ultra-Improved Stop band Rejection of an Ceramic Filter Using Ridge Resonators
SINDH UNIVERSITY RESEARCH JOURNAL -SCIENCE SERIES, 2020
This paper proposes improved design techniques for microwave filters to aid spurious performances... more This paper proposes improved design techniques for microwave filters to aid spurious performances of an monolithic ceramic waveguide resonator filter, with low insertion loss and good quality factor.The improved spurious performance of a filter is due to introduction of ridge in first and last resonator. The proposed filter design provide good miniaturization and with improved spurious performance up to 30%. Simulated result of the filteris in a good agreement with the theoretical concept which further confirms the validity and accuracy of designs without compromising the merits like Quality factor, return losses etc.
Ultra-Wideband Bow-tie Antenna for Ground Penetrating Radar Applications
SINDH UNIVERSITY RESEARCH JOURNAL -SCIENCE SERIES, 2019
The Ground-penetrating radar (GPR) system is used for the detection of buried objects inside the ... more The Ground-penetrating radar (GPR) system is used for the detection of buried objects inside the earth and the classification of the subsurface structures. Ultra-wide band antenna is one of the major component of the GPR system; which is used to transmit and receive short pulse of electromagnetic nature. The performance of the GPR system in detecting buried object is mainly affected by the reflections of the GPR antenna. The reflections from the antennas itself is a basis of late-time ringing and distortion of antenna. These factors create problem in the identification of the objects. Several UWB antennas are used in the GPR system. This paper presents theoretical study for the design of ultra-wideband Bow-tie antenna as a GPR antenna. Bow-tie antenna is designed for a frequency range of 4-18 GHz. Transient and spectral behavior of the antenna is simulated. The time behavior of the antenna shows a reflected signal from the bow-tie antenna of the duration of 2.0 ns. The antenna provides a VSWR less than 2.0 and a return loss of less than -15 dB in the operating frequency range. Bow-tie antenna is then modeled and simulated in the GPR environments which includes the buried object (i.e. scatterer) and beam floor. The design, modeling and simulations are performed by using CST Microwave Studio.
Telemonitoring System for Healthcare
SINDH UNIVERSITY RESEARCH JOURNAL -SCIENCE SERIES, 2018
This paper addresses about telemonitoring system. Recently, a lot of advancement has been carried... more This paper addresses about telemonitoring system. Recently, a lot of advancement has been carried out in the field medical engineering. Telemonitoring system achieved great popularity for patient healthcare. Telemonitoring system allows consultancy from physician at distance,monitoring of patient status information or suffering critical health problem,while patient reside at remote area oraway from hospital. There are numerous kind of diseases which requires immediate action e.g. cardiac abnormalities, heart attack, epilepsy etc.This paper presents a comprehensive study about healthcare for outdoor patient.Furthermore, the parameters responsible for minimum time coverage and thereby carries less delay for action has also been discussed.
Design techniques for integrated ceramic waveguide filters with N+1 controllable transmission zer... more Design techniques for integrated ceramic waveguide filters with N+1 controllable transmission zeros (TZ) is presented. The integrated dielectric filters offers considerable size reduction as compared to TEM resonators. The selectivity of the filters is increased by introducing N+1 TZ using resonant coupling structures and resonating discontinuities in the external resonators. Simulated results for two asymmetrical generalized Chebyshev designs having N-1 and N+1 TZ in the upper side of the passband are presented. Index Terms Dielectric resonators, monolithic integrated filter, Miniaturization, Transmission zeros.
Computers, Materials & Continua
The development of multimedia content has resulted in a massive increase in network traffic for v... more The development of multimedia content has resulted in a massive increase in network traffic for video streaming. It demands such types of solutions that can be addressed to obtain the user's Quality-of-Experience (QoE). 360-degree videos have already taken up the user's behavior by storm. However, the users only focus on the part of 360-degree videos, known as a viewport. Despite the immense hype, 360-degree videos convey a loathsome side effect about viewport prediction, making viewers feel uncomfortable because user viewport needs to be pre-fetched in advance. Ideally, we can minimize the bandwidth consumption if we know what the user motion in advance. Looking into the problem definition, we propose an Encoder-Decoder based Long-Short Term Memory (LSTM) model to more accurately capture the non-linear relationship between past and future viewport positions. This model takes the transforming data instead of taking the direct input to predict the future user movement. Then, this prediction model is combined with a rate adaptation approach that assigns the bitrates to various tiles for 360-degree video frames under a given network capacity. Hence, our proposed work aims to facilitate improved system performance when QoE parameters are jointly optimized. Some experiments were carried out and compared with existing work to prove the performance of the proposed model. Last but not least, the experiments implementation of our proposed work provides high user's QoE than its competitors.
Ceramic waveguide bandpass filters with spurious modes suppression
An investigation of various ceramic bandpass filters with an improved spurious performance for us... more An investigation of various ceramic bandpass filters with an improved spurious performance for use in cellular base station filtering applications is presented in this thesis. Monolithic integrated ceramic bandpass filters offer more than 50% size reduction compared to air-filled coaxial resonator filters with the same unloaded Q-factor. However, the stopband performance of these filters is deteriorated by spurious frequencies of the fundamental mode and higher order modes. The probable solution to reducing the effects of these undesired modes is to add a low-pass filter or band-stop filter at the expense of higher in-band losses and bulky volumes. In this work, multiple geometrical design techniques are explored to achieve the optimum out of band performance without any need for a low-pass filter. The improvement in spurious performance of Chebyshev ceramic bandpass waveguide filters is explored. In particular, its design solution aimed to improve the stopband attenuation for these...
Two different configuration of monolithic ceramic waveguide filters with three different width re... more Two different configuration of monolithic ceramic waveguide filters with three different width resonators is described. To increase the gap between fundamental frequency and first spurious, the change of resonator geometry is required. Therefore, three different width resonators are used to spread out the spurious resonances without degrading the performance of a filter. The proposed designs offer 70% improvement in stop band rejection in comparison with uniform width ceramic waveguide filter. Improved out of band performance of two six order filters have been presented in comparison with ceramic waveguide filter.
Spurious Free Non Uniform Width Dielectric Loaded Filters
This paper presents the design of dielectric loaded waveguide filters with wide spurious free ban... more This paper presents the design of dielectric loaded waveguide filters with wide spurious free bandwidth. Resonators loaded with non-uniform width ceramic blocks are used to spread out the higher order spurious resonances along with the silver plated hole/ridged ceramic blocks in I/O resonators to reduce the overall size of the filter. The proposed designs demonstrate 2.44 times fo spurious free bandwidth. Simulated results for a six pole Chebyshev non-uniform width ceramic blocks mixed with a hole plated ceramic loaded filter and a non-uniform width ceramic blocks mixed with a silver plated ridged ceramic loaded filter are presented in the paper exhibiting excellent spurious performance.
In this paper, an UWB micro-strip antenna design has been proposed which is suitable for future c... more In this paper, an UWB micro-strip antenna design has been proposed which is suitable for future cognitive radio applications. The geometry of proposed antenna is composed of two semi-circles with their interior modified in order to achieve higher impedance bandwidth. The semi-etched ground provides further bandwidth enhancement. The proposed antenna is fabricated on an inexpensive dielectric substrate FR-4 with relative permittivity of 4.4 and thickness of 1.6 mm. The overall dimensions of UWB antenna are 60 × 60 × 1.6 mm and have a bandwidth of 5.7 GHz. The designed antenna covers the most commonly used wireless communication bands such as DCS-1800, ISM bands, GPS, Wi-MAX, WLAN, 3G, 4G, etc. The design process and the variations in antenna’s performance due to different parameters has been discussed. The design and simulation of the antenna are carried out in the Ansys Electronic Desktop HFSS. The measured results are in good agreement with simulated results and design theory which...
Virtual output queue is the pragmatic and high performance packet switching architecture used to ... more Virtual output queue is the pragmatic and high performance packet switching architecture used to eliminate head-of-line (HOL) problem. There are some simple iterative algorithms proposed for the virtual output queue architecture and lot of research has been done. The detailed simulated analysis of iSlip, FIRM and maximum size matching algorithm called Static round robin (SRR) is investigated in this paper. The SRR (static round robin) algorithm is found more accurate and works well in variant traffic models.
Sensors
In this work, a new prototype of the eight-element MIMO antenna system for 5G communications, int... more In this work, a new prototype of the eight-element MIMO antenna system for 5G communications, internet of things, and networks has been proposed. This system is based on an H-shaped monopole antenna system that offers 200 MHz bandwidth ranges between 3.4–3.6 GHz, and the isolation between any two elements is well below −12 dB without using any decoupling structure. The proposed system is designed on a commercially available 0.8 mm-thick FR4 substrate. One side of the chassis is used to place the radiating elements, while the copper from the other side is being removed to avoid short-circuiting with other components and devices. This also enables space for other systems, sub-systems, and components. A prototype is fabricated and excellent agreement is observed between the experimental and the computed results. It was found that ECC is 0.2 for any two radiating elements which is consistent with the desirable standards, and channel capacity is 38 bps/Hz which is 2.9 times higher than 4...
IEEE Access
Reinforcement learning (RL) is an unsupervised learning technique used in many real-time applicat... more Reinforcement learning (RL) is an unsupervised learning technique used in many real-time applications. The essence of RL is a decision-making problem. In RL, the agent constantly interacts with the environment and selects the next action according to previous feedback in terms of reward. In this paper, RL trains Software-Defined Wireless Sensor Networks (SDWSNs) controller to optimize the routing paths. We combine RL and SDN, where RL is applied to the SDN controller to generate the routing tables. We also propose four different reward functions for optimization of the network performance. RL-based SDWSN improves network performance by 23% to 30% in terms of lifetime compared with RL-based routing techniques. RL-based SDWSN performs well because it can intelligently learn the routing path at the controller. In addition, it has a faster network convergence rate than RL-based WSN.
SINDH UNIVERSITY RESEARCH JOURNAL -SCIENCE SERIES
This work presents the 3 rd order ceramic waveguide filters with improved stopband performance. T... more This work presents the 3 rd order ceramic waveguide filters with improved stopband performance. The idea utilizes ceramic loaded resonators with different permittivity's and TEM loading. The overall response spreads out the higher order resonances by integrating the effects of different and TEM without affecting the overall performance of a filter. The simulated results of a 3 rd order ceramic loaded waveguide filter is presented, which is in good agreement with the idea.
The Quantitative Analysis of Round Robin Matching Scheduling Algorithms for VOQ Packet Switch Architecture
International Journal of Electronics Communication and Computer Engineering, 2012
ABSTRACT Virtual output queue is the pragmatic and high performance packet switching architecture... more ABSTRACT Virtual output queue is the pragmatic and high performance packet switching architecture used to eliminate head-of-line (HOL) problem. There are some simple iterative algorithms proposed for the virtual output queue architecture and lot of research has been done. The detailed simulated analysis of iSLIP and maximum size matching algorithm called Static round robin (SRR) is investigated in this paper. The SRR (static round robin) algorithm is found more accurate and works well in variant traffic models.
Inline Integrated Ceramic Waveguide Bandpass Filter with N+1 Finite Transmission Zeros
IETE Journal of Research
Real‐time low cost compact liquid‐water binary mixture monitoring sensor
Microwave and Optical Technology Letters, Jun 29, 2020
This work proposes a novel method for detecting the concentration of water present in liquid‐wate... more This work proposes a novel method for detecting the concentration of water present in liquid‐water binary mixture in real time with a low cost, portable measurement setup. The sensing element in the proposed system is a two‐port microstrip bandstop resonator based on coupled line open‐ended quarter wavelength section. Voltage control oscillator and power detector ICs are used to generate and detect the microwave power at specific bandstop frequency. Water concentrations in commercially available liquids are monitored both in batch and continuous mode of operation using separate 3D printed liquid containing fixtures attached to the open end of the microstrip line. The measured results successfully validate the design theory.
IEEE Access
This work presents a design technique to implement miniaturized cross-coupled bandpass filters in... more This work presents a design technique to implement miniaturized cross-coupled bandpass filters in inline physical configurations based on triple-mode resonators. Triple-mode resonances are obtained by using integrated coaxial-waveguide cavity resonators. They consist of two coaxial conducting posts placed in the sidewalls of a rectangular waveguide cavity. In the proposed triplet, a transmission zero (TZ) can be positioned at any of the two sides of the passband by simply locating the coaxial posts either on the same wall or on opposite walls of the rectangular waveguide cavity. Coaxial-to-waveguide mode coupling is implemented by means of coupling screws, which adds flexibility in terms of tuning easiness. Three 9.9-GHz proof-of-concept prototypes corresponding to third-and sixth-order integrated coaxial-waveguide bandpass filters are designed at the electromagnetic-simulation level. Furthermore, the triplet with a TZ below the passband is manufactured and characterized to experimentally validate the engineered 3-D RF filter principle and its underlying design theory. INDEX TERMS 3-D filter, bandpass filter, coaxial filter, inline filter, microwave filter, transmission zero (TZ), waveguide filter.
Ceramic Waveguide Filters with Improved Stop band Rejection and Transmission Zeros
2023 4th International Conference on Computing, Mathematics and Engineering Technologies (iCoMET)
Experiments with Neural Networks Training Algorithms for DDoS attacks Detection
SINDH UNIVERSITY RESEARCH JOURNAL -SCIENCE SERIES, 2019
Attacks on servers to bring their services down is growing rapidly. There are several possible me... more Attacks on servers to bring their services down is growing rapidly. There are several possible methods through which attackers can attack a server. Distributed denials of service (DDoS) attacks are one of these attacks types in computing environments. In this paper, we discuss the possible ways of DDoS attacks detection using artificial neural network based techniques. Here a feed forward neural network is designed to detect DDoS attacks in a network based environment. Performance of feed forward neural network is analyzed by applying three different training algorithms. These algorithms are (1) Scaled Conjugate Gradient (2) Bayesian Regularization and (3) Gradient Descent. Results show that Bayesian Regularization algorithm is better among these three training algorithms and it has less number of misclassifications.
Comparative Analysis of MIMO OFDM System Using Different Fading Techniques
SINDH UNIVERSITY RESEARCH JOURNAL -SCIENCE SERIES, 2019
The MIMO technology utilizes different antennas at each terminal of a wireless link and greatly i... more The MIMO technology utilizes different antennas at each terminal of a wireless link and greatly improves the link reliability and spectral efficiency of future wireless communication systems. This technology integrated with Orthogonal Frequency Division Multiplexing (OFDM), which is particularly proving a propitious entrant for upcoming next generation wireless systems including both mobile and fixed systems. It provides an attractive air-interface solution for next-generation wireless/cellular systems. In this paper Waterfilling algorithm has been used to optimize transmit power for maximizing the capacity. The Waterfilling algorithm successfully solved the problem of power allocation for MIMO-OFDM wireless network and adaptively allocate power to minimize BER performance and increasing the capacity in order to maintain the QoS requirements for a network. The proposed work is investigated by using Matlab tool.
Ultra-Improved Stop band Rejection of an Ceramic Filter Using Ridge Resonators
SINDH UNIVERSITY RESEARCH JOURNAL -SCIENCE SERIES, 2020
This paper proposes improved design techniques for microwave filters to aid spurious performances... more This paper proposes improved design techniques for microwave filters to aid spurious performances of an monolithic ceramic waveguide resonator filter, with low insertion loss and good quality factor.The improved spurious performance of a filter is due to introduction of ridge in first and last resonator. The proposed filter design provide good miniaturization and with improved spurious performance up to 30%. Simulated result of the filteris in a good agreement with the theoretical concept which further confirms the validity and accuracy of designs without compromising the merits like Quality factor, return losses etc.
Ultra-Wideband Bow-tie Antenna for Ground Penetrating Radar Applications
SINDH UNIVERSITY RESEARCH JOURNAL -SCIENCE SERIES, 2019
The Ground-penetrating radar (GPR) system is used for the detection of buried objects inside the ... more The Ground-penetrating radar (GPR) system is used for the detection of buried objects inside the earth and the classification of the subsurface structures. Ultra-wide band antenna is one of the major component of the GPR system; which is used to transmit and receive short pulse of electromagnetic nature. The performance of the GPR system in detecting buried object is mainly affected by the reflections of the GPR antenna. The reflections from the antennas itself is a basis of late-time ringing and distortion of antenna. These factors create problem in the identification of the objects. Several UWB antennas are used in the GPR system. This paper presents theoretical study for the design of ultra-wideband Bow-tie antenna as a GPR antenna. Bow-tie antenna is designed for a frequency range of 4-18 GHz. Transient and spectral behavior of the antenna is simulated. The time behavior of the antenna shows a reflected signal from the bow-tie antenna of the duration of 2.0 ns. The antenna provides a VSWR less than 2.0 and a return loss of less than -15 dB in the operating frequency range. Bow-tie antenna is then modeled and simulated in the GPR environments which includes the buried object (i.e. scatterer) and beam floor. The design, modeling and simulations are performed by using CST Microwave Studio.
Telemonitoring System for Healthcare
SINDH UNIVERSITY RESEARCH JOURNAL -SCIENCE SERIES, 2018
This paper addresses about telemonitoring system. Recently, a lot of advancement has been carried... more This paper addresses about telemonitoring system. Recently, a lot of advancement has been carried out in the field medical engineering. Telemonitoring system achieved great popularity for patient healthcare. Telemonitoring system allows consultancy from physician at distance,monitoring of patient status information or suffering critical health problem,while patient reside at remote area oraway from hospital. There are numerous kind of diseases which requires immediate action e.g. cardiac abnormalities, heart attack, epilepsy etc.This paper presents a comprehensive study about healthcare for outdoor patient.Furthermore, the parameters responsible for minimum time coverage and thereby carries less delay for action has also been discussed.
Design techniques for integrated ceramic waveguide filters with N+1 controllable transmission zer... more Design techniques for integrated ceramic waveguide filters with N+1 controllable transmission zeros (TZ) is presented. The integrated dielectric filters offers considerable size reduction as compared to TEM resonators. The selectivity of the filters is increased by introducing N+1 TZ using resonant coupling structures and resonating discontinuities in the external resonators. Simulated results for two asymmetrical generalized Chebyshev designs having N-1 and N+1 TZ in the upper side of the passband are presented. Index Terms Dielectric resonators, monolithic integrated filter, Miniaturization, Transmission zeros.
Computers, Materials & Continua
The development of multimedia content has resulted in a massive increase in network traffic for v... more The development of multimedia content has resulted in a massive increase in network traffic for video streaming. It demands such types of solutions that can be addressed to obtain the user's Quality-of-Experience (QoE). 360-degree videos have already taken up the user's behavior by storm. However, the users only focus on the part of 360-degree videos, known as a viewport. Despite the immense hype, 360-degree videos convey a loathsome side effect about viewport prediction, making viewers feel uncomfortable because user viewport needs to be pre-fetched in advance. Ideally, we can minimize the bandwidth consumption if we know what the user motion in advance. Looking into the problem definition, we propose an Encoder-Decoder based Long-Short Term Memory (LSTM) model to more accurately capture the non-linear relationship between past and future viewport positions. This model takes the transforming data instead of taking the direct input to predict the future user movement. Then, this prediction model is combined with a rate adaptation approach that assigns the bitrates to various tiles for 360-degree video frames under a given network capacity. Hence, our proposed work aims to facilitate improved system performance when QoE parameters are jointly optimized. Some experiments were carried out and compared with existing work to prove the performance of the proposed model. Last but not least, the experiments implementation of our proposed work provides high user's QoE than its competitors.
Ceramic waveguide bandpass filters with spurious modes suppression
An investigation of various ceramic bandpass filters with an improved spurious performance for us... more An investigation of various ceramic bandpass filters with an improved spurious performance for use in cellular base station filtering applications is presented in this thesis. Monolithic integrated ceramic bandpass filters offer more than 50% size reduction compared to air-filled coaxial resonator filters with the same unloaded Q-factor. However, the stopband performance of these filters is deteriorated by spurious frequencies of the fundamental mode and higher order modes. The probable solution to reducing the effects of these undesired modes is to add a low-pass filter or band-stop filter at the expense of higher in-band losses and bulky volumes. In this work, multiple geometrical design techniques are explored to achieve the optimum out of band performance without any need for a low-pass filter. The improvement in spurious performance of Chebyshev ceramic bandpass waveguide filters is explored. In particular, its design solution aimed to improve the stopband attenuation for these...
Two different configuration of monolithic ceramic waveguide filters with three different width re... more Two different configuration of monolithic ceramic waveguide filters with three different width resonators is described. To increase the gap between fundamental frequency and first spurious, the change of resonator geometry is required. Therefore, three different width resonators are used to spread out the spurious resonances without degrading the performance of a filter. The proposed designs offer 70% improvement in stop band rejection in comparison with uniform width ceramic waveguide filter. Improved out of band performance of two six order filters have been presented in comparison with ceramic waveguide filter.
Spurious Free Non Uniform Width Dielectric Loaded Filters
This paper presents the design of dielectric loaded waveguide filters with wide spurious free ban... more This paper presents the design of dielectric loaded waveguide filters with wide spurious free bandwidth. Resonators loaded with non-uniform width ceramic blocks are used to spread out the higher order spurious resonances along with the silver plated hole/ridged ceramic blocks in I/O resonators to reduce the overall size of the filter. The proposed designs demonstrate 2.44 times fo spurious free bandwidth. Simulated results for a six pole Chebyshev non-uniform width ceramic blocks mixed with a hole plated ceramic loaded filter and a non-uniform width ceramic blocks mixed with a silver plated ridged ceramic loaded filter are presented in the paper exhibiting excellent spurious performance.
In this paper, an UWB micro-strip antenna design has been proposed which is suitable for future c... more In this paper, an UWB micro-strip antenna design has been proposed which is suitable for future cognitive radio applications. The geometry of proposed antenna is composed of two semi-circles with their interior modified in order to achieve higher impedance bandwidth. The semi-etched ground provides further bandwidth enhancement. The proposed antenna is fabricated on an inexpensive dielectric substrate FR-4 with relative permittivity of 4.4 and thickness of 1.6 mm. The overall dimensions of UWB antenna are 60 × 60 × 1.6 mm and have a bandwidth of 5.7 GHz. The designed antenna covers the most commonly used wireless communication bands such as DCS-1800, ISM bands, GPS, Wi-MAX, WLAN, 3G, 4G, etc. The design process and the variations in antenna’s performance due to different parameters has been discussed. The design and simulation of the antenna are carried out in the Ansys Electronic Desktop HFSS. The measured results are in good agreement with simulated results and design theory which...
Virtual output queue is the pragmatic and high performance packet switching architecture used to ... more Virtual output queue is the pragmatic and high performance packet switching architecture used to eliminate head-of-line (HOL) problem. There are some simple iterative algorithms proposed for the virtual output queue architecture and lot of research has been done. The detailed simulated analysis of iSlip, FIRM and maximum size matching algorithm called Static round robin (SRR) is investigated in this paper. The SRR (static round robin) algorithm is found more accurate and works well in variant traffic models.
Sensors
In this work, a new prototype of the eight-element MIMO antenna system for 5G communications, int... more In this work, a new prototype of the eight-element MIMO antenna system for 5G communications, internet of things, and networks has been proposed. This system is based on an H-shaped monopole antenna system that offers 200 MHz bandwidth ranges between 3.4–3.6 GHz, and the isolation between any two elements is well below −12 dB without using any decoupling structure. The proposed system is designed on a commercially available 0.8 mm-thick FR4 substrate. One side of the chassis is used to place the radiating elements, while the copper from the other side is being removed to avoid short-circuiting with other components and devices. This also enables space for other systems, sub-systems, and components. A prototype is fabricated and excellent agreement is observed between the experimental and the computed results. It was found that ECC is 0.2 for any two radiating elements which is consistent with the desirable standards, and channel capacity is 38 bps/Hz which is 2.9 times higher than 4...
IEEE Access
Reinforcement learning (RL) is an unsupervised learning technique used in many real-time applicat... more Reinforcement learning (RL) is an unsupervised learning technique used in many real-time applications. The essence of RL is a decision-making problem. In RL, the agent constantly interacts with the environment and selects the next action according to previous feedback in terms of reward. In this paper, RL trains Software-Defined Wireless Sensor Networks (SDWSNs) controller to optimize the routing paths. We combine RL and SDN, where RL is applied to the SDN controller to generate the routing tables. We also propose four different reward functions for optimization of the network performance. RL-based SDWSN improves network performance by 23% to 30% in terms of lifetime compared with RL-based routing techniques. RL-based SDWSN performs well because it can intelligently learn the routing path at the controller. In addition, it has a faster network convergence rate than RL-based WSN.
SINDH UNIVERSITY RESEARCH JOURNAL -SCIENCE SERIES
This work presents the 3 rd order ceramic waveguide filters with improved stopband performance. T... more This work presents the 3 rd order ceramic waveguide filters with improved stopband performance. The idea utilizes ceramic loaded resonators with different permittivity's and TEM loading. The overall response spreads out the higher order resonances by integrating the effects of different and TEM without affecting the overall performance of a filter. The simulated results of a 3 rd order ceramic loaded waveguide filter is presented, which is in good agreement with the idea.
The Quantitative Analysis of Round Robin Matching Scheduling Algorithms for VOQ Packet Switch Architecture
International Journal of Electronics Communication and Computer Engineering, 2012
ABSTRACT Virtual output queue is the pragmatic and high performance packet switching architecture... more ABSTRACT Virtual output queue is the pragmatic and high performance packet switching architecture used to eliminate head-of-line (HOL) problem. There are some simple iterative algorithms proposed for the virtual output queue architecture and lot of research has been done. The detailed simulated analysis of iSLIP and maximum size matching algorithm called Static round robin (SRR) is investigated in this paper. The SRR (static round robin) algorithm is found more accurate and works well in variant traffic models.
Inline Integrated Ceramic Waveguide Bandpass Filter with N+1 Finite Transmission Zeros
IETE Journal of Research