Showing papers in "Aeu-international Journal of Electronics and Communications in 2023"
TL;DR: In this article , an 8-transistor (8T) carbon nanotube field effect transistor (CNTFET) based low power, stable static random access memory (SRAM) cell design with reduced write delay is presented.
Abstract: Carbon nanotube field effect transistor (CNTFET) is swiftly becoming an alternative to conventional CMOS transistors due to superior transport properties, improved current handling characteristics, and better gate control. This work presents a new Carbon nanotube field effect transistor (CNTFET) based low power, stable static random access memory (SRAM) cell design with reduced write delay. The proposed eight-transistor (8T) CNTFET-based SRAM cell improves read/write static noise margin by 1.98×/1.25×, respectively, at 0.3 V compared to conventional 6T SRAM that uses similar CNTFET parameters. The write access time and leakage power of the proposed cell are improved by 1.90× and 2.14×, respectively, compared to the conventional 6T design. The proposed design parameters are also compared with two already presented 8T SRAM cells. The simulation is performed with the Cadence Virtuoso using the Stanford University 32 nm CNTFET Verilog model.
10 citations
TL;DR: In this paper , the authors proposed a dual-band metamaterial-based antenna for 5G millimeter-wave communication networks, which is a pentagon-shaped monopole that provides a dualband response with a wide operating bandwidth at 5G 28/28 bands.
Abstract: This article presents a high-isolation metamaterial-based dual-band multiple-input multiple-output (MIMO) antenna for 5G millimeter-wave communication networks. The proposed antenna is a pentagon-shaped monopole that provides a dual-band response with a wide operating bandwidth at 5G 28/28 bands. The antenna is printed on 0.508-mm-thick Rogers RT5880 substrate of relative permittivity ɛr = 2.2. It exhibits a small physical size of 5.5 × 5.4 × 0.508 mm3, excluding the feeding line. The MIMO system is constructed of two symmetric radiating elements arranged adjacently with the mutual coupling of −18.5 dB at both resonant frequencies. The dual-band metamaterial is designed and placed between the two radiators to reduce the mutual coupling. Embedding a 3 × 1 metamaterial array enhances the isolation to −39 dB and −38 dB at 28 GHz and 38 GHz, respectively. The proposed system is capable of covering both 28/28 5G bands and has the merits of broad bandwidth, low profile, high gain (>5 dB), improved isolation (−38 dB), low envelope correlation coefficient (ECC) (<0.0001) and channel capacity loss (CCL) (<0.05), and high diversity gain (DG) (>9.99 dB). The system performance is verified experimentally with good agreement between the simulated and measured data. These properties demonstrate the system applicability for 5G millimeter-wave communication networks.
8 citations
TL;DR: In this article , two new CFOA-based first-order voltage-mode universal filters are proposed, which can give universal filter responses with the selection of their relevant inputs.
Abstract: In this paper, two new CFOA-based first-order voltage-mode universal filters are proposed. Both of the filters use an additional unity gain-inverting amplifier. The first proposed filter employs a minimum number of passive elements, while the second one includes one capacitor and two grounded resistors. The proposed filters can give universal filter responses with the selection of their relevant inputs. Both of the proposed filters enjoy the low output and high input impedances. Two quadrature oscillator circuits derived from the proposed filters are also considered as application examples. In order to see the performance of the circuits, many simulations are carried out via the SPICE program. Also, some experiments for the first proposed filter are done by using AD844s.
6 citations
TL;DR: In this article , the performance of comb-like channel field effect transistor (CombFET) and nanosheet FET (NSFET), at both device and circuit levels at the 3-nm node, is analyzed at both DC, analog/RF figures of merit (FOMs) are analyzed in detail.
Abstract: The performance of comb-like channel field effect transistor (CombFET) and nanosheet FET (NSFET) is addressed at both device and circuit levels at the 3-nm node. The CombFET is realized by combining both FinFET and NSFET structures in the channel area. At the device level, the DC, analog/RF figures of merit (FOMs) are analyzed in detail. From simulations, it is observed that the on current (ION) is enhanced by 42% from NSFET to CombFET at the same off current (IOFF) of 250 pA under the same footprint (FP). CombFET's improvement over NSFET is the result of the channel's wider effective width. Further, an improvement of 30% in cut-off frequency (fT) and a decrement of 20% in intrinsic delay (τ) is noticed from NSFET to CombFET. On top of that dimensional impact on the electrical performance of CombFET analysed in detail. The CMOS circuit behaviour for ring oscillator (RO) is studied using the Verilog-A model for both FETs in the CADENCE tool. An oscillation frequency (fOSC) of 111.9 GHz and 82.7 GHz was noticed for CombFET and NSFET, respectively. Thus, the analyses demonstrate that CombFET offers superior performance over NSFET without increasing the FP.
5 citations
TL;DR: In this paper , a design for standard ternary inverter (STI), NAND (TNAND), TNOR (TNOR) using carbon nanotube field effect transistors (CNTFETs) is proposed in which a p-type dynamic diode is used with the goal of lowering the energy consumption expressed as power delay product (PDP) and thereby reducing battery usage.
Abstract: The emergence of multi-valued logic (MVL) is a substitute to binary logic approaches for realizing high-information density logic systems and high-operating speed systems. In this paper, a design for standard ternary inverter (STI), ternary NAND (TNAND), ternary NOR (TNOR) using carbon nanotube field effect transistors (CNTFETs) is proposed in which a p-type dynamic diode is used with the goal of lowering the energy consumption expressed as power delay product (PDP) and thereby reducing battery usage. Additionally, the basic arithmetic operations are then performed using proposed ternary logic circuits, which can be extended to realize more complex operations. The proposed designs are simulated in HSPICE using a 32 nm Stanford CNTFET model. With respect to variation in process parameters, the reliability of the proposed STI circuit is examined. Simulation results verify that the proposed designs show improvement in terms of power consumption and power delay product (PDP) compared to the other CNTFET based ternary logic circuits. Moreover, less variations are observed in power and PDP of the proposed logic gates with variation in process parameters, capacitance, temperature, frequency and supply voltage. The proposed circuit designs of STI, TNAND, TNOR, ternary half adder (THA), ternary multiplier (TMUL) show 78 %, 98 %, 99 %, 99 %, 99 % improvement in PDP respectively, as compared to the conventional CNTFET based circuit designs and 99 % PDP improvement in all proposed circuits compared to CNTFET based logic circuits with resistive load.
4 citations
TL;DR: A wearable ultra-wideband MIMO antenna using conductor and polyester fiber fabrics is proposed in this paper , which has a frequency range of 2 GHz - 30 GHz, a gain of 3.75 dBi on average, and a correlation coefficient of 0.5.
Abstract: A wearable ultra-wideband MIMO antenna using conductor and polyester fiber fabrics is proposed in this paper. The antenna’s total dimension is 115 × 70 mm2. As a result, the antenna can be installed on curved or bent surfaces due to its flexibility. This proposed antenna has a frequency range of 2 GHz – 30 GHz, a gain of 3.75 dBi on average, and a correlation coefficient of 0.5. That can be utilized for interior installation of the 5G frequency spectrum (2.6 GHz and 26 GHz), as well as WBAN application (2.4 GHz, 5.2 GHz, and 3.1 GHz – 10.6 GHz). Additionally, the researchers designed an electromagnetic band gap (EBG) and constructed a square loop plate with a square plate that reflects resonance characteristics in the 2.4 GHz and 5.2 GHz bands by placing unit cells in 3 × 5 cells to decrease the antenna’s specific absorption rate (SAR). The proposed antenna with EBG could minimize the SAR values to 0.088 W/kg and 0.070 W/kg, which obtains a gain of 6.59 dBi and 11.6 dBi, at 2.4 GHz and 5.2 GHz, respectively. Also, the results are lower than the conventional SAR value of 2.0 W/kg at 10 g.
4 citations
TL;DR: In this paper , a monopulse slot array antenna with substrate integrated waveguide (SIW) has been designed and fabricated for application in tracking systems, which has circular polarization and has a very simple design.
Abstract: In this paper, a monopulse slot array antenna with substrate integrated waveguide (SIW) has been designed and fabricated for application in tracking systems. This antenna has circular polarization and has a very simple design. For increasing the efficiency of the antenna and maintaining its one-layer structure, this design utilizes two modes (TE120, TE210) to excite the slots rather than the complex feed network commonly used in monopulse antennas. The feeding ports are well-isolated due to the orthogonality of the two modes. The feeding cavity is operated in these two modes to obtain the difference and sum patterns. The proposed antenna at the center frequency of 10 GHz has an impedance bandwidth of 200 MHz, and the reflection coefficient in this bandwidth is less than −10 dB. The zero depth of the difference pattern is less than −24 dBi, while the obtained gain of the sum pattern is 13.6 dBi. The polarization axial ratio is less than 3 dB in the range of 9.98–10.02 GHz. Also, the antenna aperture efficiency is 50 % at the desired frequency.
3 citations
TL;DR: In this paper , the authors proposed two efficient rectifier configurations for potential implementation in both RF Energy Harvesting (RFEH) and WPT systems covering global sub-6 GHz 5G bands.
Abstract: In recent years, the enormous innovation in the wireless system has escalated the demands of fifth-Generation (5G) enabled RF Energy Harvesting (RFEH) and Wireless Power Transfer (WPT) systems. With this motivation, the proposed work introduces two efficient rectifier configurations for potential implementation in both RFEH and WPT systems covering global Sub-6 GHz 5G bands. The Design-1 presents a single-band rectifier covering 3.3–3.7 GHz sub-6 GHz 5G band. A dual Transmission Line (TL) based Matching Network (MN) is used to improve the rectifier performance. At 0 dBm, Design-1 achieved maximum Power Conversion Efficiency (PCE) of 76 % at 3.5 GHz and 4kΩ load. The Design-2 presents a 3.3–5 GHz broadband rectifier circuit that covers the entire sub-6 GHz 5G bands. A MN based on multi-stepped TL is used to improve the rectifier performance for the broad frequency band and achieved a PCE greater than 35 % and 50 % at 0 and 9 dBm, respectively at a load value of 1kΩ. For validation, prototypes of both rectifiers are fabricated and a very good agreement between simulated and measured results is achieved. The proposed rectifier configurations hold immense potential for implementation across nations and offer a global solution to self-sustainable low-powered 5G battery-less devices.
3 citations
TL;DR: In this paper , the outage probability (OP) performance for multiple-input multiple-output non-orthogonal multiple access (MIMO-NOMA) based EH relaying network was investigated.
Abstract: This paper investigates the outage probability (OP) performance for multiple-input multiple-output non-orthogonal multiple access (MIMO-NOMA) based energy harvesting (EH) relaying network. The base station communicates multiple users with the assistance of EH-relay. The optimal transmit antenna selection/maximal ratio combining (TAS/MRC) and sub-optimal majority-based TAS (TAS-maj)/MRC are employed in the first and second hops, respectively. We first derive the signal-to-interference-and-noise ratio (SINR) expressions. Then, the derived SINR expressions are used to obtain expressions of OP for each user in closed form in Nakagami-m fading channels. We finally verify the exactness of the theoretical analysis with the numerical results through Monte Carlo simulations. The results show that the outage performance improves considerably with the increased number of transmit and/or receive antennas and the enhanced channel conditions. Furthermore, regardless of the antenna’s configurations, the optimal position of the EH-based relay has to be close to the base station, while the optimal power division ratios for users vary. Moreover, the proposed TAS/MRC scheme is superior to the previous schemes, such as max–max–max and max–min–max-based MRC.
3 citations
3 citations
TL;DR: In this paper , the authors investigated the synchronization of the recently proposed memristive Hindmarsh-Rose neuron maps under different coupling conditions: electrical synapse, chemical synapses, inner linking functions, and hybrid synapses.
Abstract: The importance of the synchronization emergence in neuronal networks has motivated many researchers to study this phenomenon. However, dealing with the systems in the discrete-time domain is more straightforward and underemphasized. Therefore, neuronal maps have recently been widely used in investigating different collective behaviors of the interacting neurons, including synchronization. Besides, the study of the memristors in neuronal models or as a synaptic function in neuronal networks is another prominent subject of interest nowadays. In fact, the magnetic induction impact on the membrane potential can be considered by the memristors in neuronal models or networks. Hence, in this paper, we investigated the synchronization of the recently proposed memristive Hindmarsh–Rose neuron maps under different coupling conditions: electrical synapses, chemical synapses, inner linking functions, and hybrid synapses. In each case, we analyzed the stability of the synchronous solution using the master stability functions. Also, we calculated the time-averaged synchronization error as a numerical verification. We found that memristive Hindmarsh–Rose neurons synchronize when they are coupled through electrical and hybrid synapses, while through chemical synapses, they cannot reach a synchronous solution. Also, we showed that a slightly lower coupling value is needed to synchronize the neurons interacting through inner linking functions than the electrical synapses.
TL;DR: In this article , a dual-band 6-port MIMO antenna for WiFi, LTE, and carrier aggregation system applications is proposed, which consists of a defected annular ring, slots, an array structure, a neutralization block, and a novel isolation structure for enhancement of bandwidth, coupling, isolation, gain, and efficiency.
Abstract: This article describes a novel dual-band 6-port MIMO antenna for WiFi, LTE, and carrier aggregation system applications. The proposed antenna consists of a defected annular ring, slots, an array structure, a neutralization block, and a novel isolation structure (GP-3) for enhancement of bandwidth, coupling, isolation, gain, and efficiency. After systematic investigation of the reference antenna (A-0; 0.65λ0 ×0.48λ0mm2) at the design frequency of 2.4 GHz, an optimized antenna (A-4) with ground plane GP-3 is selected among the antennas (A-1 to A-4). The proposed antenna resonates in dual-band, with a lower band (1.6–2.45 GHz (simulated), 1.57–2.39 GHz (measured)) due to ports P5 and P6, and a higher band (2.3–2.6 GHz (simulated), 2.3–2.58 GHz (measured)) due to ports P1, P2, P3 and P4. A peak realized gain of 2.2 dB and 3.34 dB at resonance frequencies of 1.7 GHz and 2.45 GHz is obtained, respectively. The proposed antenna exhibits a maximum isolation and total efficiency of 45.6 dB and 88%, respectively. Simulated results by means of HFSS version 18 are validated with experimental results of the proposed work.
TL;DR: In this article , a diamond-shaped dual-band bandpass filter with seven transmission zeros in the stopband and two poles in each passband is designed, analyzed, and implemented.
Abstract: In this paper, a compact diamond-shaped dual-band bandpass filter with seven transmission zeros in the stopband and two poles in each passband is designed, analyzed, and implemented. The proposed filter consists of coupled lines and stepped impedance open stubs. Theoretical analysis based on lossless transmission line theory is carried out to verify the transmission zero frequencies. A filter prototype with center frequencies of 1.17 GHz and 2.85 GHz is fabricated to exhibit the feasibility of the design. The prototype is printed on a 0.79 mm Rogers RT Duroid 5880 with a dielectric constant of (ϵr = 2.2) and occupies an area of 0.29λg × 0.17λg, where λg is the guided wavelength at the first center frequency. The experimental results show a 3-dB fractional bandwidth of 13.65% and 3.5% at low and high center frequencies, respectively. The simulated and experimented frequency responses are consistent with each other.
TL;DR: In this paper , an innovative substrate coupling simulation methodology with on-the-fly extraction and validation of CMOS substrate parasitic elements, combining boundary element method (BEM) with a computational python based physical layout extraction and RC modeling method, is presented.
Abstract: An innovative substrate coupling simulation methodology with on-the-fly extraction and validation of CMOS substrate parasitic elements, combining boundary element method (BEM) with a computational python based physical layout extraction and RC modeling method, is presented in this work. The proposed methodology is seamlessly integrated into the standard virtuoso based custom circuit design flow and allows the designer to extract fast and accurate a substrate RC mesh, valid from DC to GHz, enabling crosstalk impact estimation and gaining insight on substrate coupling effects from the early stage of the design process until the prototype phase. The proposed substrate crosstalk modeling flow is validated using a 20 GHz VCO circuit as a crosstalk victim. The VCO vehicle is designed using a 65 nm RFCMOS process and the respective RF devices of the specific PDK are used. The PCB transmission line and the package parasitics must be considered as to achieve more accurate and realistic simulation results. The simulation scheme is set using a layout footprint test case and two separate signal injection tap points, each at a certain distance from the VCO victim. This simulation scheme can provide various substrate signal crosstalk scenarios by injecting signals that consist of multiple frequencies into the substrate. Three simulation analysis types, Transient, QPSS and ENVLP, are performed as to be able to designate which analysis is the most suitable for crosstalk simulation in terms of simulation time, accuracy and compatibility. Finally, as a sanity check and methodology validation, crosstalk isolation trends with respect to the aggressor distance and the substrate signal frequency are extracted and compared with the State-of-the-Art results available in literature.
TL;DR: In this paper , the authors proposed a novel high gain 4-element dual-band multiple-input multiple-output (MIMO) antenna for 5G wireless applications, where a crescent shape is created initially from a circular structure and then the proposed antenna is formed by using slots and Defected Ground Structures (DGS) to set resonances at the desired frequencies.
Abstract: In this paper, a novel high gain 4-element dual-band multiple-input multiple-output (MIMO) antenna is proposed for fifth generation (5G) wireless applications. A crescent shape is created initially from a circular structure and then the proposed antenna is formed by using slots and Defected Ground Structures (DGS) to set resonances at the desired frequencies. The proposed MIMO antenna operates both at 28 GHz and 38 GHz frequencies. In addition, the MIMO antenna has 3.05 GHz and 2.41 GHz bandwidth at those frequencies, respectively. The antenna elements are orthogonally placed to each other as a design concept to enhance the isolation between the elements up to 30 dB. Moreover, the MIMO antenna has maximum measured gains of 8.14 dB and 8.04 dB at 28 GHz and 38 GHz, respectively. The antenna size achieves compactness with the total size of 60 × 60 × 0.508 mm3. The designed MIMO antenna is also evaluated in terms of important MIMO parameters such as diversity gain (DG), envelope correlation coefficient (ECC), mean effective gain (MEG), and channel capacity loss (CCL). The proposed antenna is a great candidate for modern 5G applications that require both wideband and high gain properties with its MIMO antenna parameters of DG, ECC , MEG and CCL.
TL;DR: In this paper , a high-performance programmable membership function generator (MFG) using 7 nm FinFET technology was proposed for on-chip image processing applications, which can generate S-shaped, Z-shaped and Gaussian-shaped membership functions.
Abstract: In fuzzy systems, efficient programmable membership function generators (MFGs) are the canonical point for the fuzzification process. This work demonstrates a high-performance programmable MFG using 7 nm FinFET technology. The proposed MFG can generate S-shaped, Z-shaped, Gaussian-shaped, and Generalized Bell-shaped membership functions. The proposed design employs 14 FinFETs to control the produced waveforms’ position, height, width, and slope. According to the simulations, the proposed MFG offers remarkable improvements in transistor count (39%), power-delay product (PDP) (54%), absolute error (45%), and root mean square error (36%) compared to the previous MFGs. The proposed design has been utilized for image enhancement to evaluate the performance of the proposed MFG in realistic environments. The image enhancement simulation results indicate a higher peak signal-to-noise ratio (PSNR) and structural similarity index metric (SSIM) than previous related works. A figure of merit (FoM) is defined considering the image enhancement quality metrics and circuit efficiency to benchmark the entire performance of the proposed MFG. The FoM simulations demonstrate that the proposed design shows an excellent trade-off between the circuit performance and image enhancement quality. Our results confirm that the proposed MFG is suitable for developing high-performance on-chip image processing applications.
TL;DR: In this paper , the authors address the specifics of short-range communications employing OAM-carrying waves generated by small uniform circular arrays (UCAs) at lower, i.e., 10 GHz, transmission frequencies.
Abstract: The orbital angular momentum (OAM or vortex) waves are expected to provide ten-fold and larger increases in wireless data rates, required for short-range communications within the beyond 5G and 6G concept of all-connected life and industry. We address the specifics of short-range communications employing OAM-carrying waves generated by small uniform circular arrays (UCAs) at lower, i.e., 10 GHz, transmission frequencies. Comparing the link budgets obtained using (i) asymptotic analytical formulas, (ii) numerical electromagnetic simulations, and (iii) measurements on two pairs of manufactured prototypes comprising 8 microstrip-patch-element UCAs, we point out the limitations of simplified models which do not account for various effects, such as coupling, parasitic radiation, and insertion loss. The observed effects are expected to be relevant at millimeter-wave frequencies as well.
TL;DR: In this article , a computer vision hand rehabilitation assessment suite is proposed, which stands as a virtual alternative to the real-world scenarios, integrating all the original tests' guidelines and procedures into an interactive computer vision experience that utilizes bleeding edge technologies such as MediaPipe Hands.
Abstract: Post-stroke patients very commonly present upper limb deficits, while their rehabilitation comprises regular monitoring and kinematic assessments to evaluate motor recovery. The Box and Block Test (BBT), as well as the Sollerman Hand function Test (SHT), are two of the most used and recommended tools to objectively measure upper limb dexterity, in addition to evaluating the rehabilitation of fine motor skills in patients. However, the tests themselves require the use of very specific equipment, along with the physical attendance of a therapist, making the whole procedure time consuming and clinic dependent. This paper proposes a computer vision hand rehabilitation assessment suite, which stands as a virtual alternative to the real-world scenarios. Our application integrates all the original tests’ guidelines and procedures into an interactive computer vision experience that utilizes bleeding edge technologies such as MediaPipe Hands for hand and finger tracking. This innovative tool requires neither any additional computer peripherals (smart gloves, VR headsets) nor any kind of extra physical equipment (wooden box, blocks), but works instead with just a mid-range PC and a camera. Our system can be deployed in residential spaces via modern 5G/6G or FTTx networks, and the test results can be sent remotely to any physician or rehabilitation expert. Finally, we shortly discuss some technical issues of our approach, as well as present some future directions regarding our tool’s score normalization and feature expansion.
TL;DR: In this paper , a simple superstrate is used to enhance the gain of a circularly polarized (CP) Fabry-Perot resonator antenna (FPRA) while maintaining a simple antenna structure.
Abstract: This communication presents a method to enhance the gain of a circularly polarized (CP) Fabry-Perot resonator antenna (FPRA) by using a simple superstrate. The proposed superstrate is a polarization conversion metasurface (PCM) which is capable of partial reflection and CP transmission phase manipulation. The partial reflection property of PCM is used to form FPRA with a feed, and the linear to circular polarization conversion capacity make the antenna realize CP radiation. Furthermore, the PCM can also correct the aperture field phase distribution of the antenna through tuning the CP transmission phase of each unit. Then the gain of the CP FPRA can be further improved. Finally, the CP radiation and gain enhancement of the FPRA are achieved by a simple superstrate without the need to add additional antenna structure. This makes the proposed antenna keep a simple structure. The performance of the antenna is verified by comparing the test results of the fabricated antenna with the simulation results. Measured results show that the antenna can realize well CP radiation at 10 GHz. After phase correction, the measured peak gain of the antenna is increased by 1 dB, reaches 18.2 dBic. The method proposed in this communication provides a new idea for improving the gain of CP FPRA while maintaining simple antenna structure.
TL;DR: In this paper , a simple optically transparent polarization and angular insensitive triple and dual band terahertz (THz) metamaterial absorber (MMA) is designed and analyzed.
Abstract: A simple optically transparent polarization and angular insensitive triple and dual band Terahertz (THz) Metamaterial Absorber (MMA) is designed and analysed in this paper. The MMA consists of three layers, dielectric layer is placed in-between the ground plane and top metallic patch. Without using stacked layers, doping and multiple resonators the absorber is designed here. The metal and substrate used here is Indium Tin Oxide (ITO) and Polyethylene Terephthalate (PET). The ITO with PET combination produces the optical transparency. The important thing in this work is the same design produces the triple and dual band operation while changing the top patch radius value. The absorber produces the triple band operation when the radius of the top circle is 65 μm and it produces the dual band when the radius of the top circle is 55 μm. It covers the frequency ranges from 0.3 THz to 1.4 THz. The designed structure is analysed by electric field, magnetic field distribution and surface current distributions. This structure is polarization and angle independent up to 90 degrees. From the parametric analysis, we found this absorber will work in both triple and dual band operation. So, this bifunctional working absorber will find more applications in optically transparent devices, sensing and imaging.
TL;DR: In this article , the Al2O3 ceramic-based filtenna is designed and inspected and the different parameters of the proposed antenna such as, |S11| and gain, are optimized and predicted using different machine learning (ML) techniques i.e. deep neural network (DNN), random forest, and XG boost.
Abstract: In this communication, Al2O3 ceramic-based filtenna is designed and inspected. The different parameters of the proposed antenna such as, |S11| and gain, are optimized and predicted using different machine learning (ML) techniques i.e. deep neural network (DNN), random forest, and XG boost. An optimized value obtained from various ML algorithms is compared with the value obtained HFSS EM simulator and experimental result. Good agreement is obtained among all. The proposed radiator works between 2.4 GHz and 2.71 GHz with a gain value of 5.0 dBi. Out of the operating frequency, the gain value decreases drastically i.e. −15 dBi at 2.27 GHz and −21 dB at 2.81 GHz. Omnidirectional types of far-field characteristics in both the principal plane and filtering features make the proposed radiator suitable (B41/n41) Bands.
TL;DR: Based on the phase transition properties of vanadium dioxide (VO2), a novel tunable metamaterial device with functions of broadband absorption and broadband polarization conversion is constructed in this paper , which can efficiently convert the incident linearly polarized terahertz (THz) wave into its crosspolarized state.
Abstract: Based on the phase transition properties of vanadium dioxide (VO2), a novel tunable metamaterial device with functions of broadband absorption and broadband polarization conversion is constructed. The proposed structure operates in the broadband absorption mode when the VO2 is in the metallic state. The simulation results demonstrated that the absorbance can achieve more than 90% with a relative bandwidth of 76.9% in the frequency range of 1.80-4.05THz. When VO2 is in the insulating state, the proposed structure operates in the broadband polarization conversion mode. In the frequency range of 1.68-3.79THz, it can efficiently convert the incident linearly polarized terahertz (THz) wave into its cross-polarized state. The polarization conversion ratio (PCR) is above 90% and the relative conversion bandwidth is larger than 77.1%. Furthermore, for the two operating modes, it has acceptable tolerance of incident angles and polarization angles. These advantages make the proposed VO2-based dual-functional metamaterial device have potential applications in many THz areas, such as absorption, polarization conversion, imaging, and so on.
TL;DR: In this article , the second harmonic of the oscillation is generated, delayed, and then fed back to the tail transistor, as a self-injection, in CMOS parallel LC-tank oscillators.
Abstract: This article studies the impact of injecting the second harmonic of the oscillation to the tail transistor, as a self-injection, in CMOS parallel LC-tank oscillators. In this scheme, the second harmonic of the oscillation is generated, delayed, and then fed back to the tail transistor. Employing the injection locking theory, closed-form formulas are derived that predicts 1/f2 phase noise arising from various noise sources in the oscillator. These formulas are validated against SpectreRF simulation results for different injection amplitudes and phases. It is shown that the phase-noise performance is improved by increasing the injection strength while the phase shift of the injected signal is set to zero. This improvement is attributed to increase oscillation amplitude and decrease phase noise factor. The amplitude and phase stability of the architecture is also analyzed in this article. Furthermore, as a case study that employs the described self-injection technique, a self-switching bias oscillator is investigated. Phase noise simulations show that the studied circuit, delivers 5 dB better phase noise, compared to the conventional class-B tail-biased oscillator.
TL;DR: In this article , a new approach of using an MCFOA structure to design the fractional-order filters that operate in current-mode is presented, which provides wide dynamic range, low noise, low THD and is suitable for low voltage/power applications.
Abstract: In this study, low-pass and high-pass current-mode fractional-order shelving filters were designed for use in acoustic applications. The filter’s architecture has two main components, Modified Current Feedback Operational Amplifier (MCFOA) active block structure based on Bipolar Junction Transistors (BJTs) and a minimum number of only grounded passive elements. These components enable the filter to operate in current-mode and low voltage/power applications. The grounded capacitor design uses a 5th-order Oustaloup approximation and a properly configured Foster type-I RC network. The main advantage of the fractional-order shelving filters is that they provide an extra order of freedom in the transition slope from the passband to the stopband, improving the listening experience. In this paper, a new approach of using an MCFOA structure to design the fractional-order filters that operate in current-mode is presented. The filters provide current-mode circuit advantages such as wide dynamic range, low noise, low THD and are suitable for low voltage/power applications. The results from theoretical calculations, along with simulations of the filters were compared and verified. From the obtained data, it was observed that the cut-off frequency of 2 kHz is suitable to be used in acoustic applications.
TL;DR: In this paper , a low-profile, compact, high-gain antenna solution for four-port mm-wave broadband MIMO communication in a 5G environment is presented, which consists of two rectangular patches connected through a corporate feed network and two quarter-wavelength square-shaped CSRRs on the ground plane.
Abstract: In this paper, a low-profile, compact, high-gain antenna solution for four-port mm-wave broadband MIMO communication in a 5G environment is presented. The proposed antenna design consists of two rectangular patches connected through a corporate feed network and two quarter-wavelength square-shaped CSRRs on the ground plane. The overall size of the proposed four-port orthogonal MIMO configuration is 28.3 mm x 28.3 mm x 0.508 mm. The antenna operates on the 5G frequency bands of n257, n258, and n261 with an effective bandwidth of 3.9 GHz covering the range of 26.5 GHz to 30.4 GHz. The suggested MIMO antenna attained a peak gain of 11 dBi and radiation efficiency of 96% at 28 GHz resonating frequency. The MIMO configuration utilized DGS to minimize near-field coupling current at the ground plane, resulting in high port-to-port isolation of >40 dB, and co-pol to X-pol isolation improvements of >9 dB and >19 dB in the boresight direction of E-plane and H-plane at 28 GHz resonating frequency. The antenna’s superior diversity performance is supported by several performance metrics, including ECC(<0.0001), DG(>9.999 dB), CCL(<0.12 bits/sec/Hz), MEG (< -3 dB), and TARC. Moreover, the linear transmission property of the proposed MIMO antenna is also validated through the variation of group delay (<0.6 ns) over operating frequency bands in the far-field region.
TL;DR: In this paper , a wideband LC-tank CMOS voltage controlled oscillator (VCO) employing a transformer-based variable inductance structure is presented, which allows four different inductances to be delivered by the structure.
Abstract: A wide-band LC-tank CMOS voltage controlled oscillator (VCO) employing a transformer-based variable inductance structure is presented. The variable inductance is obtained through a switching scheme that controls the current path in a transformer and allows four different inductances to be delivered by the structure. Additionally, an electric model of the transformer obtained through the simulated data and equations based on its physical properties is proposed. The inductance and quality factor from the variable structure were extracted from the transformer’s electromagnetic simulations and model’s scattering parameters. The model showed and error lower than 4% in all modes of operation inside of the desired range (from 1 to 6 GHz). The proposed VCO is simulated and shows a percentual tuning range of 87.9% around a central frequency of 4.12 GHz, while consuming less than 3.3 mW of power and exhibiting a maximum phase noise of -108 dBc/GHz occupying an area of 0.45 mm2.
TL;DR: In this paper , a low-profile broadband circularly polarized folded transmitarray antenna (CPFTA) is proposed to reflect the y-polarized waves and transmit x-polarsized waves into right-handed circularly polarized waves.
Abstract: In this communication, a novel design of compact and low-profile broadband circularly polarized folded transmitarray antenna (CPFTA) is reported. A broadband linear-to-circular polarization conversion metasurface (PCM) with multi-mode operation is initially developed as the sub-reflector, to reflect the y-polarized waves and transmit x-polarized waves into right-handed circularly polarized waves. Additionally, by rotating the circularly polarized transmitters, geometric phase can be exploited for phase compensation. Then, a linear-to-linear PCM with high efficiency is designed as the main reflector. As verification, a CPFTA integrated with a broadband planar feed source and the proposed high-efficiency PCMs at X band is designed, fabricated, and experimentally characterized. The measured results are in good accordance with the simulated ones, revealing a −10 dB impedance bandwidth of 28.7%, a 3 dB gain bandwidth of 22.9%, and a 3 dB axial ratio bandwidth of 31.9%. Meanwhile, the achieved peak gain is 25.2 dBi at 10.35 GHz with a maximum aperture efficiency of 28.3%. Combining the advantages of broadband operation, flat gain, and ease of integration, the proposed CPFTA is an attractive candidate for modern wireless communications.
TL;DR: In this article , a transmission model, which considers the effect of the boundary layer thickness on viscous friction and pipe materials on characteristic impedance, has been proposed, and the accuracy of the model is verified through experiments.
Abstract: Mud pulse telemetry (MPT) is a low-cost borehole wireless communication scheme in the oil drilling industry. Drilling mud is used as the medium to deliver logging information via mud pressure pulses. However, the data transmission rate is severely limited by poor channel conditions. To overcome the existing limitations and to achieve the full potential of the MPT, a transmission model, which considers the effect of the boundary layer thickness on viscous friction and the effect of pipe materials on characteristic impedance, has been proposed. Then, the accuracy of the model is verified through experiments. Finally, the channel characteristics are analysed and discussed based on the model. The results demonstrate that the MPT channel is a time-varying multipath channel with significant symbol timing offsets, carrier frequency offsets, frequency selective fading, and inter-symbol interference issues. Based on the model simulation results, countermeasures are proposed.
TL;DR: In this paper , a shared-aperture transmissive/reflective bi-functional metasurface is proposed to achieve near full phase coverage for orthogonally polarized transmitted and reflected wave.
Abstract: In this paper, a shared-aperture transmissive/reflective bi-functional metasurface is proposed. On metasurfaces, antisymmetric dipole pairs as transmissive elements and symmetric dipole pairs as reflective elements are interleaved in orthogonal polarization. By utilizing Huygens’ resonance, the metasurface can achieve near full phase coverage for orthogonally polarized transmitted and reflected wave. Then the bi-functional metasurface is used for the design of transmitarray (TA)/reflectarray (RA) bi-functional antenna. The measured results show that, for TA, the maximum gain is 30.26 dBi with antenna efficiency of 45.6 % and the 3-dB gain bandwidth is 26.3–29.3 GHz (10.79 %), and for RA, the maximum gain is 30.29 dBi with antenna efficiency of 45.7 % and the 3-dB gain bandwidth entirely covers the frequency region of 26–30 GHz. The bi-functional metasurface has important applications in the field of antenna engineering.