Showing papers in "Aeu-international Journal of Electronics and Communications in 2020"
TL;DR: This paper uses the replicator dynamics to analyze the evolutionary process of IoT devices and proves that multi-user computation offloading exists unique Evolutionary Stability Strategy (ESS), and designs an evolutionary game algorithm based on reinforcement learning in practical application scenarios.
Abstract: Due to the limited computing resources and energy of IoT devices, complex computing tasks are offloaded to sufficient computing servers, such as Cloud Center. However, offloading may increase the latency and congestion of the IoT network. Mobile Edge Computing (MEC) is a promising approach, which can decrease the delay and energy consumption of IoT devices significantly. In this paper, we investigate the problem of multi-user computation offloading under dynamic environment. Considering the channel interference when multiple IoT devices offload computing tasks via wireless channels at the same time, we formulate the computation offloading as an evolutionary game model. We use the replicator dynamics to analyze the evolutionary process of IoT devices and prove that multi-user computation offloading exists unique Evolutionary Stability Strategy (ESS). Finally, we design an evolutionary game algorithm based on reinforcement learning in practical application scenarios. Experiments can verify the convergence and performance of the proposed algorithm in multi-user scenarios.
85 citations
TL;DR: In this article, an extensive review of GaN HEMT based power amplifier is presented, where different thermal management solutions used for GaN power amplifier to cope with its self heating phenomenon are explained.
Abstract: The unique material properties of GaN, wide bandgap, high thermal conductivity, high breakdown voltage, high electron mobility and the device properties of GaN HEMT (High Electron Mobility Transistor) namely low parasitic capacitance, low turn on resistance and high cut off frequencies make it a good choice to use in a power amplifier. During this era of wire- less communication with complex modulation schemes having high peak to average power ratio, maintaining the efficiency and linearity of power amplifier is a tough task. In this paper an extensive review of GaN HEMT based power amplifier is presented. First of all, GaN technology is described and compared with other semiconductor technologies. The different classes of power amplifier like class B, C, D, E, F and J with GaN is discussed. Efficiency and linearity enhancement techniques like envelope tracking, Doherty power amplifier and digital predistortion used in applications with high PAPR waveforms is described. The advantages of GaN MMIC (Microwave Monolithic Integrated Circuit) are reviewed. Finally different thermal management solutions used for GaN power amplifier to cope with its self heating phenomenon are explained.
70 citations
TL;DR: In this paper, a compact and low-frequency broadband microwave metamaterial absorber (MMA) based on meander wire structure loaded with lumped resistor has been proposed and investigated numerically and experimentally.
Abstract: In this paper, a compact and low-frequency broadband microwave metamaterial absorber (MMA) based on meander wire structure loaded with lumped resistor has been proposed and investigated numerically and experimentally. Compared with the single meander wire structure, the bandwidth and absorption level of the proposed MMA loaded with lumped resistors can be improved extremely. The retrieved equivalent constitutive parameters and simulated electric and magnetic fields distributions have been demonstrated to illustrate the mechanism underlying observed absorption. The simulated results exhibit that the proposed MMA can keep a good stability in a wide angular range for both transverse electric (TE) and transverse magnetic (TM) waves under normal and oblique incidence. Further simulated results indicate that the performance of the MMA can be adjusted by changing parameters of unit-cell structure and lumped resistors. Finally, we have fabricated a modified MMA sample practically, composing of meander wire structure loaded with lumped resistors, FR-4(loss), foam and continuous metal film. The modified MMA yields absorbance of over 85% from 1.84 GHz to 5.96 GHz in the experiment, and the relative bandwidth is about 105.6%, which is agreement reasonable with simulation.
61 citations
TL;DR: In this paper, an ultra-compact two-port MIMO antenna working in the frequency range of 3.1-10.6 GHz with dual band-notched characteristics is presented.
Abstract: In this paper, an ultra-compact two-port MIMO antenna working in the frequency range of 3.1–10.6 GHz with dual band-notched characteristics is presented. The MIMO antenna consists of two identical octagonal-shaped radiating elements placed adjacent to each other with a connected ground plane. The overall size of the proposed two-port UWB-MIMO antenna is 19 × 30 × 0.8 mm3. In the ground plane of antenna elements, a T-shaped stub is introduced to create band-notch at 5.5 GHz. Also, an open-ended half-guided-wavelength resonator slot is introduced along the upper edge of the octagonal radiator to obtain a broader notched-band (4.37–5.95 GHz). The second band-notch is created around 7 GHz (6.52–7.45 GHz) by etching another open-ended slot from the radiating patch. The two-notch bands reject interference due to HiperLAN, WiMAX, INSAT/Super-extended C-band, downlink of X-band satellite communication and RFID service bands. A pair of L-shaped slits are introduced in the feed line to improve impedance matching, for the frequency band available between the two notches. The proposed design is fabricated on an FR-4 substrate and minimum isolation greater than 18 dB (a major portion >22 dB) and envelope correlation coefficient (ECC) less than 0.13 are obtained. The antenna gain varies in the range of 1.2–2.91 dBi with a variation of 1.71 dBi only. A radiation efficiency, greater than 70% is achieved throughout the operating frequency band.
61 citations
TL;DR: A novel single-feed circularly polarized patch antenna for dual-band (2.6 and 3.4 GHz) applications is presented and down-tilt beams achieved that are particularly suitable for wall-mount base-stations are achieved.
Abstract: This article presents a novel single-feed circularly polarized patch antenna for dual-band (2.6 and 3.4 GHz) applications. Details of the design procedure and design considerations of the proposed antenna are described. The novelties of the proposed antenna are counted by (i) a meaningful Jia-shaped patch used as the primary radiator; (ii) a 3D L-shaped feeding probe used to excite the stacked patches so that the near degenerate-modes are excited at the desired dual band; (iii) down-tilt beams achieved that are particularly suitable for wall-mount base-stations. The measured 3-dB axial-ratio bandwidths are 2.41–2.61 GHz and 3.25–3.42 GHz, where the maximum gains are recorded as 7.3 and 6.3 dBic, respectively. Methods for the adjustment of band ratio down to 1.18 are discussed. The overall antenna size is 100 × 100 × 12.8 mm3.
54 citations
TL;DR: In this article, a very compact and closely spaced circular-shaped MIMO antenna with slotted T-shaped stubs and protruded strips for high isolation is discussed, and the fractional bandwidth of the proposed model reaches 134.68% from 2.82 GHz to 14.45 GHz with S11.
Abstract: A very compact and closely spaced circular-shaped UWB – MIMO antenna with slotted T-shaped stubs and protruded strips for high isolation is discussed in the present paper. The fractional bandwidth of the proposed model reaches 134.68% from 2.82 GHz to 14.45 GHz with S11
53 citations
TL;DR: The MSCA (Multi-Strategy Channel Allocation algorithm for edge computing) algorithm presented in this paper can minimize channel interference and overall network energy consumption while satisfying throughput and end-to-end delay.
Abstract: Wireless mesh networks (WMNs) are a kind of wireless network technology that can transmit multi-hop information, and have been regarded as one of the key technologies for configuring wireless machines. In WMNs, wireless routers can provide multi-hop wireless connections between nodes in the network and access the Internet through gateway devices. Multicast is a communication technology that uses best effort to send information from a source node to multiple destinations. In this paper, we study the problems of channel interference and time slot multi-user collisions caused by radio during WMNs information transmission. Through innovative use of edge computing technology to construct a node data cache model and step-by-step calculation of node channel separation, a multi-strategy channel allocation algorithm for edge computing is proposed. The mechanism of this algorithm is to use edge computing technology to pre-store the data in the nodes in the multicast tree and calculate the channel separation between the nodes, and then select the transmission channel number of the node with the least interference to avoid mutual interference between node information transmissions. Through experimental tests and comparisons, the MSCA (Multi-Strategy Channel Allocation algorithm for edge computing) algorithm presented in this paper can minimize channel interference and overall network energy consumption while satisfying throughput and end-to-end delay.
48 citations
TL;DR: A CBTA-based universal mutator circuit is proposed for the realization of memcapacitor and meminductor elements and frequency dependent hysteresis loops are obtained.
Abstract: In this work, a CBTA-based universal mutator circuit is proposed for the realization of memcapacitor and meminductor elements. Proposed mutator circuit contains only one CBTA element, one memristor and one capacitor. It is suitable to transform a grounded memristor to a floating memcapacitor or meminductor. SPICE simulation by using a CBTA designed with 0.18 μm level-7 TSMC CMOS transistors was performed to show the accuracy of the proposed circuit and as a result, frequency dependent hysteresis loops are obtained.
43 citations
TL;DR: In this paper, a low-profile wearable antenna with metamaterial (MM) for wireless body area network (WBAN) applications is presented, which operates in the ultra-wideband (UWB) between 4.55 and 13 GHz and it has a thickness of 4.68mm.
Abstract: In this paper, a low-profile wearable antenna with metamaterial (MM) for wireless body area network (WBAN) applications is presented. The designed antenna with MM operates in the ultra-wideband (UWB) between 4.55 and 13 GHz and it has a thickness of 4.68 mm. To the best of our knowledge, it is the lowest thickness reported in the literature for UWB antennas with MM. The proposed is designed and manufactured using fully flexible textiles. The designed antenna was simulated in free space and on the human body model. Simulation results show that gain, directionality, and front-to-back ratio of the antenna increase considerably with the placement of the MM. Also, in simulations, it is found that the specific absorption rate (SAR) values for the designed antenna reduce by 98.3% when MM is used. These SAR values calculated for the designed antenna with MM are well below the limits defined in European standards. The designed antenna and metamaterials were manufactured, too, and scattering parameters were measured. Measurement results are in good agreement with the results found in the simulations. It shows that the proposed antenna is very suitable for use in WBAN applications due to its low thickness, having low SAR, and UWB operation.
43 citations
TL;DR: The proposed antenna achieves compact operation along with an omnidirectional radiation pattern having gain and efficiency in the range over 1.1 dBi and 78% for the proposed frequency bands.
Abstract: A novel dual branch multiband compact slotted antenna for digital broadcasting, wireless and sub 6 GHz 5G is presented. Antenna achieves multiband characteristics at (750–790 MHz) Digital broadcasting, (1.41–1.45 GHz) wireless medical telemetry, (2.10–2.14 GHz) Universal Mobile Telecommunication Service (UMTS), (3.44–3.51 GHz) WiMAX/sub 6 GHz 5G, (3.80–3.87 GHz) Sub 6 GHz 5G, (5.17–5.20 GHz) wireless local area network (WLAN) and (5.97–6.38 GHz) fixed satellite communication by introducing slots in the form of inverted U and E shape having varied branch lengths and full ground plane. The antenna has an overall size of 30 × 30 × 1.6 mm3. The proposed antenna achieves compact operation along with an omnidirectional radiation pattern having gain and efficiency in the range over 1.1 dBi and 78% for the proposed frequency bands. The antenna is fabricated after optimizing the geometrical dimensions where measured results match well with simulated ones.
42 citations
TL;DR: In this paper, the authors presented a CPW fed wideband four element multiple input multiple output (MIMO) antenna with isolation less than 30 dB between the antenna elements with an Envelope Correlation Coefficient (ECC) below 0.003, measured gain between 2.4 dBi & 5.9 dBi and the radiation efficiency is well above 90% over the entire operating range.
Abstract: This paper presents a CPW fed wideband four element multiple input multiple output (MIMO) antenna.
The MIMO structure is developed from the analysis of a single wideband CPW fed antenna with �10 dB
bandwidth of 1700 MHz. After which a two antenna element structure is analyzed having the same bandwidth range with isolation below �50 dB. Finally, the proposed four element MIMO structure is designed
with isolation less than 30 dB between the antenna elements with an Envelope Correlation Coefficient
(ECC) below 0.003, measured gain between 2.4 dBi & 5.9 dBi and the radiation efficiency is well above
90% over the entire operating range. The targeted applications lie between 4.3 and 6.0 GHz under the
C band spectrum for WLAN and Wi-Fi. The proposed design is printed on a uniquely shaped FR4 substrate
to achieve low insertion loss and greater isolation between the antenna elements. The edge-to-edge distance between the adjacent antenna elements is 15 mm keeping which the antenna elements are placed
on the arms of the substrate pattern. This also further helps in increasing the number of antenna elements just by extending the armed pattern with constant edge-to-edge distance. The important parameters of the MIMO system such as ECC with a value as low as 0.0002, Diversity Gain (DG) of 9.998 dB, Total Active Reflection Coefficient (TARC), Mean Effective Gain (MEG) measuring the ratio < 3 dB and Channel Capacity Loss (CCL) of 0.0635 bits/s/Hz are observed at the center frequency of 5 GHz. All the
necessary simulations are carried out in Ansys HFSS
TL;DR: In this article, a modified Sierpinski carpet fractal ultra-wideband (UWB) multiple-input-multiple-output (MIMO) antenna with a square-shaped funnel-like ground stub is presented and experimentally investigated.
Abstract: In this paper, a compact modified Sierpinski carpet fractal ultra-wideband (UWB) multiple-input-multiple-output (MIMO) antenna with a square-shaped funnel-like ground stub is presented and experimentally investigated. Miniaturization and wideband performance are achieved by using the proposed fractal structure. Iterated function system (IFS) method is used to design the proposed fractal structure. The self-similarity dimension of the proposed fractal structure is 1.72. The dimension of the proposed MIMO antenna is 24 × 30 mm2 and consists of two novels modified Sierpinski carpet fractal monopole-antenna elements. The impedance bandwidth of the presented antenna is 9.6 GHz (S11
TL;DR: The numerical results show that the performance at two destinations can be maintained at the same level with proper power allocation, and for each value of the PB transmit power, there exists an optimal value for the EH time duration to improve the performance of both users.
Abstract: In this paper, we analyze the performance of a novel communication scheme that combines three new techniques, namely energy harvesting (EH), full-duplex (FD) relay and cooperative non-orthogonal multiple access (NOMA). In this scheme, both the source and the relay harvest energy from the power beacon (PB) at the first phase of the transmission block and then use the harvested energy to transmit messages during the remaining phase. In this proposed EH-FD-NOMA system, the FD relay employs the amplify-and-forward scheme. We consider two destinations, one of them is far from the FD relay and the other is near the FD relay. Based on the mathematical calculation, we derive the closed-form expressions for the outage probability (OP) of the two users of interest. The numerical results show that the performance at two destinations can be maintained at the same level with proper power allocation. Furthermore, for each value of the PB transmit power, there exists an optimal value for the EH time duration to improve the performance of both users. In addition, the impact of the residual self-interference (RSI) due to imperfect self-interference cancellation (SIC) at the FD relay is also considered. Finally, numerical results are demonstrated through Monte-Carlo simulations.
TL;DR: In this article, the authors show that the classical linear charge-voltage relationship of ideal capacitors, q = C · v, is not valid for CPEs and that the relationship is nonlinear and can be expressed as q = c ( v ; C α, α ) · v.
Abstract: The constant phase element (CPE) or fractional-order capacitor is an electrical device that has an impedance of the form Z ( s ) = 1 / C α s α , where C α is the CPE parameter and α is a fractional dispersion coefficient of values between 0 and 1. Here we show that in the time-domain the classical linear charge-voltage relationship of ideal capacitors, q = C · v , is not valid for CPEs. In fact the relationship is nonlinear and can be expressed as q = C ( v ; C α , α ) · v . We verify our findings using (i) circuit simulations of an integer-order emulator of a CPE, and (ii) experimental results from a commercial supercapacitor as well as an in-house fabricated device based on carbon film materials.
TL;DR: The phenomena of miniaturization and multiband operation along with a wideband are compared with state-of-the-art antennas presented in the literature to highlight the significance and novelty of the proposed antenna.
Abstract: A miniaturized frequency reconfigurable CPW-fed antenna operating in the UWB, ISM, WiMAX, WLAN, Wi-Fi, C-band and 5G sub-6 GHz frequency bands is proposed here. The wideband CPW-fed triangular patch is made tunable to three triple-frequency bands on demand by connecting it to different serpentine stubs by using PIN diodes. The combination of triangular patch and serpentines introduced overall 8 number of operating bands (2.45, 3.05, 3.3, 4.1, 4.6, 5, 6 and 6.2 GHz) instead of a wideband (3.78–7.08 GHz) generated by triangular patch. The simulation results of the antenna are in good agreement with the measured results. The phenomena of miniaturization and multiband operation along with a wideband are compared with state-of-the-art antennas presented in the literature to highlight the significance and novelty of the proposed antenna. The proposed antenna has its applications in compact and portable devices operating at multiple frequency bands like, cellular phones, Tablets, Wi-Fi devices etc.
TL;DR: In this paper, the design and development of a dual-band and dual-polarized two-port multiple-input-multiple-output (MIMO) antenna for mid-band 5G (3.4-3.6 GHz) and C-band (4-8 GHz) applications is presented.
Abstract: This paper presents the design and development of a dual-band and dual-polarized two-port multiple-input-multiple-output (MIMO) antenna for mid-band 5G (3.4–3.6 GHz), and C-band (4–8 GHz) applications. The antenna design is very simple and it mainly consists of a circular-shaped single split-ring resonator on the top side of the substrate which is coupled with the microstrip line feed line. The bottom side is comprised of a rectangular-shaped defected ground structure. Due to this dual-band response is obtained and the first band shows linear polarization and the second band provides circular polarization. The entire dimensions of the intended two-port MIMO antenna are 46 mm × 21 mm × 1.6 mm. The antenna measured results offer a wider impedance bandwidth (IBW) of 20.22% and 44.07% for the two bands centered at 3.54 GHz and 6.33 GHz respectively. Also, the proposed MIMO antenna shows minimum isolation of 15 dB for the two frequency bands with a smaller edge-to-edge spacing of 4 mm (0.04λ0) between the two antenna elements. Moreover, the second band provides an axial ratio bandwidth of 3.97% centered at 6.78 GHz. The antenna shows excellent IBW, good isolation between the single antenna elements without the use of any decoupling mechanism, better antenna gain, and improved envelope correlation coefficient by maintaining smaller antenna size compared to similar types of existing two-port MIMO antennas in literature.
TL;DR: In this paper, a plasmonic structure consisting of Silicon and SiO2 substrate, graphene layer, and metal nano-grating in near-infrared range is proposed, and the optical response of the proposed structure is numerically simulated using the finitedifference time-domain (FDTD) method.
Abstract: Graphene-based photodetectors have been caught in the spotlight of optoelectronics devices and they are significant candidates for tunable detectors. Unfortunately, little reports are presented for absorption enhancement in near-infrared range. Therefore, here, a graphene-based photodetector with plasmonic structure consisting of Silicon and SiO2 substrate, graphene layer, and metal nano-grating in near-infrared range is proposed. The optical absorption of graphene layer in this structure increases due to the occurrence of plasmonic effects and excitation of surface plasmon polaritons (SPPs) in metal and graphene interface. The optical response of the proposed structure is numerically simulated using the finite-difference time-domain (FDTD) method. To optimize the optical absorption of the structure, the effects of geometrical parameters, the chemical potential of graphene, the number of graphene layers, and the incident angle have been investigated. Based on numerical results, the absorption of monolayer graphene enhanced from 0.023 to nearly 0.70, even to a maximum value of 0.80 in three-layer graphene and the total absorption of optimized structure reached to about 0.98 at telecommunication wavelength (1.55 μ m). Moreover, the absorption spectrum of the proposed structure can be tuned by either changing the geometrical parameters of nano-grating or chemical potential of graphene.
TL;DR: This paper presents performance analysis of downlink NOMA (DL-NOMA) system in presence of successive interference cancellation (SIC) error over Rayleigh fading channels and derives the exact closed-form expressions of bit error rate (BER) at near-user and far-user for the considered DL-N OMA system.
Abstract: Non-orthogonal multiple access (NOMA) scheme is an emerging 5G technology to improve upon the spectral efficiency. It can support more users than the number of available frequency-,time-, and code-domain resources. The innovation behind NOMA technology is to exploit non-orthogonal resource allocation at the cost of receiver complexity to mitigate the inter-user interference arising due to non-orthogonal signals. In this paper, we present performance analysis of downlink NOMA (DL-NOMA) system in presence of successive interference cancellation (SIC) error over Rayleigh fading channels. In particular, we derive the exact closed-form expressions of bit error rate (BER) at near-user (U1) and far-user (U2) for the considered DL-NOMA system. Besides, we also present the achievable rate analysis of the considered NOMA system and it is observed that its achievable rate is higher as compared to conventional orthogonal multiple access (OMA) schemes. Further, we also determine the optimized power allocation coefficient for the NOMA system. The analytical results are corroborated with the Monte-Carlo simulations. The simulation results are presented for different modulation schemes and for different NOMA scenarios. A close argument between the analytical and simulation results validate our analysis.
TL;DR: It has been found that the modified Lorenz PRNG has the best randomness quality and the best hardware performance as it can pass all the NIST tests while operating at 298.597 MHz.
Abstract: This paper presents a multiplierless based FPGA implementation for six different chaotic Pseudo Random Number Generators (PRNGs) that are based on: Chua, modified Lorenz, modified Rossler, Frequency Dependent Negative Resistor (FDNR) oscillator, and other two systems that are modelled using the simple jerk equation. These chosen systems can be employed in high speed applications because they don’t utilize any hardware multiplier. The proposed PRNGs have been implemented using VHDL, synthesized on Xilinx, using the FPGA: XC5VLX50T, and tested using the NIST statistical suite. Furthermore, a comparison has been established between the performance of all the PRNGs, regarding the implementation area, speed, and the statistical randomness quality. It has been found that the modified Lorenz PRNG has the best randomness quality and the best hardware performance as it can pass all the NIST tests while operating at 298.597 MHz and utilizing only 0.23% and 0.62% from the FPGA’s slice registers and Look-Up-Tables (LUTs) respectively.
TL;DR: In this design biasing lines required for biasing of the diode are placed away from the radiating structure and the pattern search algorithm is used for the optimization of antenna feed for achieving impedance matching.
Abstract: The paper presents the design of a frequency and pattern reconfigurable rectangular patch antenna using a single PIN diode switch. The use of single PIN diode reduces the complexity of the biasing network required for the diode. The proposed antenna can work in two different modes and resonates at 2.47 GHz, 3.8 GHz, and 5.36 GHz with the capability to change the radiation pattern. In this design biasing lines required for biasing of the diode are placed away from the radiating structure and the pattern search algorithm is used for the optimization of antenna feed for achieving impedance matching. These are the two improvisations made in the presented design as compared to the existing designs in literature.
TL;DR: A Dual-Output Operational Transconductance Amplifier and Differential Voltage Current Conveyor-based fully floating emulator which enables the memristor current to flow in both directions when used with other circuit elements is presented.
Abstract: In this paper, we have presented a Dual-Output Operational Transconductance Amplifier (DO-OTA) and Differential Voltage Current Conveyor (DVCC)-based fully floating emulator which enables the memristor current to flow in both directions when used with other circuit elements. The proposed memristor consists of only one DO-OTA, one DVCC, one grounded capacitor that is attractive for an integrated circuit, and two PMOS transistors operating as an electronic resistor. The proposed fully floating memristor emulator includes two very important features: (1) the fixed and variable memductance parts of the circuit are electronically adjustable, and (2) both incremental and decremental circuit behaviors can be obtained without altering the circuit topology. The circuit was laid using the Cadence Spectre Analog Environment with TSMC 0.18 µm process parameters and occupied a layout area of only 119 µm × 90 µm. The post-layout simulation results for the memristor circuit were obtained for different operating frequencies and all simulations were fully compatible with the experimental memristor behaviors. Finally, the memristor circuit was built on a breadboard using discrete circuit elements, and all experimental results were also compatible with the expected memristor characteristics.
TL;DR: The FPGA hardware realization for all integer, fractional, and mixed-order new Wang chaotic system is proposed and achieves about a 10x reduction in the hardware resources of chaotic systems implementation compared with the previous work.
Abstract: This paper introduces a study for the effect of using different floating-point representations on the chaotic system’s behaviour. Also, it offers a comparison between the attractors at three different orders, (integer, fractional, and mixed-order). This comparison shows the minimum number of bits needed for all parameters to simulate the chaotic attractor in each case. Numerical simulations using Matlab are presented for all discussed chaotic systems. This study opens the door to implement chaotic systems and different applications digitally with low hardware area. The FPGA hardware realization for all integer, fractional, and mixed-order new Wang chaotic system is proposed. The proposed realization achieves about a 10x reduction in the hardware resources of chaotic systems implementation compared with the previous work. Also, the chaotic system at three different orders (integer, fractional, and mixed) are employed in a sound encryption scheme. Two speech files are used to test the scheme which shows good results. They are simulated by Xilinx ISE 14.7 and implemented on Xilinx Vertix-5 FPGA kit using Verilog hardware description language. The three systems show great results in terms of MSE, entropy, correlation coefficient, and pass the NIST test.
TL;DR: The concurrence among the diverse numerical and experimental outcomes supports the candidature of the suggested layout for portable UWB as well as UWB MIMO systems.
Abstract: This paper numerically proposes and experimentally investigates a compact coplanar waveguide fed two element ultra-wideband (UWB), multiple-input–multiple-output (MIMO) antenna array accompanying peak isolation and triple band notch mechanism. The proposed antenna consists of two identical printed monopole elements along with the incorporation of multiple 2nd order Hilbert defects in the ground structure and proposes to incorporate three different mechanisms to reduce the electromagnetic interference of the UWB antenna with existing narrowband systems. The measured impedance bandwidth for the intended antenna ranges from 2.7 GHz to 11.22 GHz. The incorporation of notch mechanisms provides interference suppression at the C-band (3.7–4.2 GHz), WLAN (5.15–5.825 GHz), and X-band communication (7.9–8.4 GHz). The overall size of the intended UWB MIMO antenna is 30.75 mm × 37.80 mm. Moreover, the diversity parameters of the proposed UWB MIMO antenna are numerically calculated and empirically investigated, these calculations and investigations depicts high diversity performance. It is noteworthy to observe that the spacing between the elements is staggeringly reduced to 2 mm. The concurrence among the diverse numerical and experimental outcomes supports the candidature of the suggested layout for portable UWB as well as UWB MIMO systems.
TL;DR: A generalization, attractor control and multi-scroll generation method for fractional-order chaotic systems through rotation transformation and a novel synchronization-dependent colored image encryption and secure communication scheme is proposed.
Abstract: This paper presents a generalization, attractor control and multi-scroll generation method for fractional-order chaotic systems through rotation transformation. A novel synchronization-dependent colored image encryption and secure communication scheme is also proposed. The systems with dynamic rotation angle fit successfully in a generalized dynamic switched synchronization scheme. Dynamic control switches specify whether the system acts as a master or slave. Dynamic scaling factors determine whether the master is a single system or a combination of two or more systems. Simulation results validate successful synchronization when rotating fractional-order systems act as slave or master or both. The proposed synchronization is suitable for one-to-one, one-to-many, mutual interconnection and role switching communication applications. The proposed synchronization-dependent image encryption scheme performs rotation angle modulation using the plaintext and XOR logic operation for plaintext image substitution. The performance of the chaotic systems as Pseudo-Random Number Generators (PRNGs) is validated using National Institute of Standards & Technology (NIST). Three synchronization scenarios are tested using Lena image. The performance of the scheme is evaluated through the encrypted image, histogram and its uniformity through chi square test, pixel correlation, Mean Squared Error (MSE), entropy, Peak Signal-to-Noise Ratio (PSNR), key sensitivity, resistance to brute force, differential and other security attacks.
TL;DR: In this paper, performance evaluation of linearity and intermodulation distortion of novel nanoscale Gallium Nitride (GaN) Silicon-on-Insulator (SOI) N-channel FinFET (n-FinFET) for RFIC design was simultaneously compared with conventional Si-based and bulk GaN-based Fin-FET with 8-nm gate length and it was found that the proposed device enhances on-current (ION) by four times and thereby transconductance, subthreshold slope, threshold voltage, surface potential, and energy band (
Abstract: This work presents, performance evaluation of linearity and intermodulation distortion of novel nanoscale Gallium Nitride (GaN) Silicon-on-Insulator (SOI) N-channel FinFET (n-FinFET) for RFIC design and results so obtained are simultaneously compared with conventional (Si-based) FinFET and bulk GaN-based FinFET with 8 nm gate length. It is found that the proposed device enhances on-current (ION) by four times and thereby transconductance, subthreshold slope, threshold voltage, surface potential, and energy band (conduction band energy and valence band energy) profiles have been improved at ultra-low voltage power supply (VDS = 0.1 V). Thus, the improved electrical performance of GaN-SOI FinFET makes it suitable for low power and high-performance CMOS circuits. Also a further investigative study has been performed on the linearity behavior of GaN-SOI FinFET and the outcomes of the study have been compared with the results of the GaN Bulk FinFET and the conventional Silicon FinFET. The SOI device shows better linear performance in the likes of higher-order voltage and current intercept points as VIP2, VIP3, IIP3, and 1-dB compression point with lesser harmonic distortions as HD2, HD3 and, IMD3. Thus, the results with higher efficiency, better linearity, and distortionless performance pave the way for RFIC design.
TL;DR: In this paper, a compact coplanar waveguide (CPW)-fed quasi-elliptical self-complementary antenna (QESCA) exhibiting super-wideband (SWB) characteristics with dual-band notches for four-port multiple-input-multiple-output (MIMO) systems is presented.
Abstract: In this paper, a compact coplanar waveguide (CPW)-fed quasi-elliptical-self-complementary antenna (QESCA) exhibiting super-wideband (SWB) characteristics with dual-band notches for four-port multiple-input-multiple-output (MIMO) systems is presented. In order to achieve better inter-element isolation and polarization diversity, the four radiating elements of the MIMO antenna are placed orthogonal to each other. Each MIMO antenna element has an elliptical shape conductor patch and a slot, which is a complement of similar shape, both present on the same side of the substrate. At each port, the proposed antenna shows excellent SWB characteristics (1.25–40 GHz), providing a bandwidth ratio of 32:1. Further, two independent slits are loaded on each antenna element to reject Wi-MAX (3.5 GHz) and WLAN (5.5 GHz) bands from SWB. Inter-element isolation of more than 18 dB up to 15 GHz and over 25 dB in the higher frequency range is obtained. Measured parameters of the fabricated MIMO antenna prototype are in good agreement with the simulated results.
TL;DR: The effect of randomness caused by the Beaulieu-Xie fading channel on the performance of physical layer security and the closed-form expressions for lower-bound of secrecy outage probability and strictly positive secrecy capacity for the said channel are studied.
Abstract: With the expansion of IoT and device-to-device communication applications, the security and privacy of the information have been kept at the forefront. The existence of a secondary eavesdropper, which attempts to access the confidential information of the legitimate partners, makes the data communication insecure. In this regard, we study the effect of randomness caused by the Beaulieu-Xie fading channel on the performance of physical layer security. To this end, the analysis for the secrecy outage probability (SOP) and average secrecy capacity (ASC) is carried out. Further, we derived the closed-form expressions for lower-bound of secrecy outage probability and strictly positive secrecy capacity (SPSC) for the said channel. To get more insight into the system, the high-power and low-power analysis of the ASC are also provided. Besides, the impact of different fading parameters on the system matrices is also investigated. Finally, the theoretical results are verified via extensive Monte Carlo simulations.
TL;DR: In this paper, the authors proposed a simple improvement technique based on the use of high n-type doping concentration at the level of carbon nanotube underneath the gate while keeping the junctionless paradigm that facilitates tremendously the fabrication processes of ultrascaled FETs.
Abstract: Carbon nanotube field-effect transistors (CNTFETs) and their growing applications are becoming part of modern nanoelectronics, which is in urgent need for high-performance ultrascaled transistors. Sub-10-nm junctionless ballistic carbon nanotube field-effect transistors (JL-CNTFET) with substantial improved performance are computationally proposed herein. The non-equilibrium Green's function (NEGF) simulation is used for the computational assessment. The proposed simple improvement technique is based on the use of high n-type doping concentration at the level of carbon nanotube underneath the gate while keeping the junctionless paradigm that facilitates tremendously the fabrication processes of ultrascaled FETs. It has been found that the proposed doping profile can significantly mitigate several ultrascaling effects while boosting the performance of sub-10-nm JL-CNTFETs. The recorded enhancements include the leakage current, current ratio, subthreshold swing, switching speed, switching energy, drain-induced barrier lowering, and threshold voltage roll-off. The significant improvements obtained in this work for sub-10-nm JL-CNTFETs, make the proposed strategy, which is simple, feasible, and efficient, as a promising technique for improving ultrascaled FETs endowed with other gate geometries and channel nanomaterials while paving the way towards high-performance sub-5-nm FETs.
TL;DR: In this article, an ultra-wideband circular cross slot artificial magnetic conductor (CCS-AMC) based low profile ultra wideband (UWB) antenna is designed and implemented.
Abstract: In this article, an ultra-wideband circular cross slot artificial magnetic conductor (CCS-AMC) based low profile ultra-wideband (UWB) antenna is designed and implemented. Reflection phase bandwidth (±90°) of 63.47% (5.7 to 11.0) GHz is achieved using the proposed CCS-AMC. Integration of CCS-AMC with UWB antenna improves the radiation pattern and gain for entire UWB range. Impedance bandwidth of 129.41% (2.4 to 11.2) GHz is achieved for the final prototype. In order to verify the concept, a UWB antenna with a compact size of (0.31 × 0.31 × 0.1) λo, (λo is the wavelength corresponding to the lowest operating frequency at 3.1 GHz) is fabricated and experimentally validated with CCS-AMC. Average gain improvement of 3.5 dBi (3–10.5 GHz) and a peak gain of 8.5 dBi at 8 GHz are obtained. Miniaturized structure with high gain makes this prototype a better candidate, especially for outdoor UWB application.
TL;DR: This paper presents a straightforward design procedure to achieve some of the best performance of this class of microstrip filters, composed of three different polygonal-shaped resonators, two of which are responsible for stopband improvement and one of which is designed to enhance the selectivity of the filter.
Abstract: This paper presents a very efficient design procedure for a high-performance microstrip lowpass filter (LPF). Unlike many other sophisticated design methodologies of microstrip LPFs, which contain complicated configurations or even over-engineering in some cases, this paper presents a straightforward design procedure to achieve some of the best performance of this class of microstrip filters. The proposed filter is composed of three different polygonal-shaped resonators, two of which are responsible for stopband improvement, and the third resonator is designed to enhance the selectivity of the filter. A holistic performance assessment of the proposed filter is presented using a Figure of Merit (FOM) and compared with some of the best filters from the same class, highlighting the superiority of the proposed design. A prototype of the proposed filter was fabricated and tested, showing a 3-dB cut-off frequency (fc) at 1.27 GHz, having an ultrawide stopband with a suppression level of 25 dB, extending from 1.6 to 25 GHz. The return loss and the insertion loss of the passband are better than 20 dB and 0.25 dB, respectively. The fabricated filter has a high FOM of 76331, and its lateral size is 22.07 mm × 7.57 mm.