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In this article, a novel transmission line model consisting of open stubs and a one-end connected coupled line is introduced as an alternative to the standard quarter wavelength transmission line (QWTL). The new transmission line unit is used to realize a highly compact branch-line balun. Even and odd mode analysis is employed to extract the closed-form design equations. To substantiate the theoretical analysis, a branch-line balun with f 0 = 0.9 GHz is implemented on a biodegradable substrate material and tested. The developed prototype is having a relative circuit area of 11.2% of the conventional balun. The measured results exhibit that the return loss is better than 20 dB. A good match is found between the simulated and tested results. [ABSTRACT FROM AUTHOR]

This paper exhibits the design and implementation of a compact dual-band bandpass filter on paper substrate. The proposed filter which works on the principle of signal interference technique has a parallel combination of short-circuited coupled line and an H-shaped network of transmission lines with open stubs. Due to the superposition of signals of the two transmission paths, a second order dual-band bandpass response with four transmission zeroes is achieved. To validate the proposed design, theoretical analysis using the lossless transmission line model is carried out and acknowledged. The developed dual-band filter prototype with center frequencies 1.17 GHz and 4.06 GHz has 3-dB fractional bandwidths of 82.56% (0.69–1.656 GHz) and 20.59% (3.645–4.481 GHz), respectively. The simulated and experimental results are in good congruence with each other. The proposed dual-band bandpass filter can be used in various wireless applications, for example, Global System for Mobile Communications (880–915 MHz), Aircraft surveillance (960–1215 MHz), Indian Regional Navigation Satellite System (1.164–1.188 GHz), Amateur radio (1.24–1.30 GHz), Global Positioning System (1.559–1.61 GHz), Satellite phones (1.616–1.626 GHz), and Satellite communication (3.7–4.2 GHz). [ABSTRACT FROM AUTHOR]

A flexible paper based and dual-band antenna is designed for UMTS service (1.9 GHz) and WiMAX services (5.8 GHz). Flexible paper is used as a substrate for the printed antenna. Expanded graphite ink is used to enable printing the antenna on the substrate. The antenna has been designed, simulated, fabricated, and measured. Steps of preparing the conductive printed ink and fabrication of the antenna have been discussed. The conductivity of the printed antenna is measured to be 1 × 104 S/square and the thickness is also measured with an average of 30 µm. Through the whole paper, good agreement between simulated and measured results is satisfied. In addition to the achieved flexibility, the antenna has demonstrated good measurement results. First, the antenna has a bandwidth of 300 MHz at 1.9 GHz and 400 MHz at 5.8 GHz with fractional bandwidth of 15.7% and 6.8% at the both bands, respectively. Second, the measured antenna radiation pattern has indicated that it is omnidirectional at 1.9 GHz and approximately omnidirectional at 5.8 GHz. Third, The antenna gain is 1.266 dB and 0.512 dB at the two bands, respectively. Finally, the antenna's efficiency at the both bands is 35% and 55%. [ABSTRACT FROM AUTHOR]

This paper investigates the digital performance of novel charge plasma based complementary (CPJL) FinFET inverters in terms of low and high noise margins, logic swing LS, DC power consumption P DC , rise t r and fall t f times, and propagations delay at both 10 and 7 nm technology nodes. In addition, their performance is compared with equivalent junctionless (JL) CFinFET inverters. Obtained results are physically analyzed including quantum–mechanical effects. Furthermore, the oscillation frequency of a three-stage ring oscillator constructed with CPJL-CFinFETs is computed, and compared with their JL-CFinFET counterpart. Our findings reveal that while dissipating less OFF-state power, t r and t f of the proposed CPJL inverter exhibit significant reduction of ~73.92% and ~79.82%, respectively, relative to its equally sized JL inverter value at 10 nm technology node. Moreover, the oscillation frequency of a three-stage ring oscillator (RO) built with CPJL inverters exhibits ~323.75% enhancement compared to its JL RO at 10 nm node. [ABSTRACT FROM AUTHOR]

In this paper the design of a digital step attenuator with simultaneous low phase and gain error characteristics is investigated. First, the loading effect of the consecutive blocks of an N-bit attenuator on the precision of the attenuation levels is analyzed. Then a modified structure to decrease the loading effect as well as the phase error of the attenuator blocks is presented. A comprehensive analysis of the circuit is performed and some design guidelines have described. Finally, a 6-bit attenuator with attenuation range of 0.5–31.5 dB and resolution of 0.5 dB is implemented in 0.18 µm complementary metal–oxide-semiconductor (CMOS) technology. The root mean square (RMS) gain error and RMS phase error of the designed circuit for different process corners and DC to 18 GHz are below 0.59 dB and 4.2°, respectively. [ABSTRACT FROM AUTHOR]

Traditional target recognition has low precision and the data processing is complicated when recognizing multiple targets. A multiple target recognition and position identification circuit based on memristor is designed in this paper, which can simultaneously realize the recognition for multiple targets with different shapes. The dual recognition is used in the designed recognition circuit, including position identification and size recognition, which will improve the recognition accuracy. Integral holding module and double threshold detection module with variable threshold based on memristor can flexibly construct the circuit according to different requirements, and the application range of the circuit is expanded. The signal processing module is designed in this paper to effectively filter out redundant targets and improve the reliability of the circuit. Different from the existing target recognition technologys, the multiple target recognition circuit based on memristor adopts the method of analog circuit to provide reference for the further development of target recognition. [ABSTRACT FROM AUTHOR]

Limitations in current fuel cell technology lead to instability in output voltage for hydrogen fuel cells, particularly under the influence of temperature variations and fuel flow fluctuations, thereby affecting the normal operation of hydrogen-powered vehicles. Improving the motor drive control system and optimizing energy management are crucial for enhancing overall vehicle performance. To improve dynamic response speed while suppressing harmonics, this paper proposes a predictive control strategy for high-speed permanent magnet synchronous motors with LCL filter in hydrogen fuel cell electric vehicles. The proposed control strategy suppresses high-frequency current harmonics by sampling only the current on the motor side, enabling fast predictive control of the high-order system motor-side current. Additionally, to mitigate the issue of unstable torque output of the electric motor at low fuel levels, this paper proposes a new composite predictive torque trajectory control strategy based on the previous control strategy. This strategy ensures rapid and accurate tracking of motor output torque, particularly during decreases in fuel cell output voltage. Experimental results validate the feasibility and effectiveness of the proposed control strategies in this paper. • Torque stability control of hydrogen electric vehicle under low fuel state. • Predictive current direct control for LCL-equipped high-speed PMSM drive based on single-sensor. • A composite predictive current trajectory control strategy balancing small steady-state error and fast dynamic response. [ABSTRACT FROM AUTHOR]

The escalating demand and complexity of monitoring services handled by Network Operations Centers (NOCs) have led Mobile Network Operators (MNOs) to prioritize automated solutions for network fault detection and diagnosis. Consequently, various Machine Learning (ML)-based Root Cause Analysis (RCA) systems have been developed, however their lack of explainability poses a challenge due to the predominantly black-box nature of ML models. This paper addresses this issue by presenting a supervised clustering methodology capable of integrating both glass-box and black-box models, the latter complemented by post-hoc explainability techniques. While black-box models excel in predictive capabilities, necessitating post-hoc techniques for explainability, glass-box models prioritize transparent decision-making, fostering a clearer understanding of the model's behavior. This work delineates a methodology for performing RCA of faults in the User Downlink (DL) Average Throughput Key Performance Indicator (KPI), simultaneously comparing the performance of black-box models (Light Gradient-Boosting Machine (LightGBM) and Extreme Gradient Boosting (XGBoost)) with glass-box models (Logistic Regression (LR) and Explainable Boosting Machine (EBM)). Results revealed that the LightGBM black-box algorithm coupled with the SHapley Additive exPlanations (SHAP) method demonstrated superior performance in fault detection and diagnosis, without compromising the overall explainability. Consequently, it was possible to identify faults related to radio conditions, low network usage in specific user groups, low network capacity, and mobility issues. The paper concludes with practical mitigation strategies for each identified fault cluster. • Supervised clustering detects and diagnoses critical mobile network KPI failures. • LightGBM + SHAP outperformed other models in detecting User DL THP faults. • The methodology diagnosed User DL faults as radio, usage, capacity, and mobility. [ABSTRACT FROM AUTHOR]

During the design of a Doherty power amplifier (DPA), the phenomenon of peaking PA turning on in advance is commonly observed. This is mainly due to the feedback of the main PA signal to the gate of the peaking PA through the gate-drain feedback capacitor, which results in an increase in its gate voltage. As a result, the overall efficiency of the back-off region is significantly reduced. This paper first describes the phenomenon of peaking PA turning on in advance. The formula for the voltage (referred to as the feedback gate voltage, FGV) imposed on the gate of the peaking PA by the main PA signal is then deduced. On this basis, the FGV is analysed numerically. For verification, an asymmetric DPA with a 9 dB output back-off (OBO) power level is designed and fabricated in this paper using GaN CGH40010F and CGH40025F transistors. According to the measurement results, the saturated drain efficiency of the DPA is 53.5%–63.3% in the 0.75–1.25 GHz band, the efficiency at the 9 dB OBO level is between 45.5%–54%, and the saturated output power is between 45 dBm–45.7 dBm, with a saturation gain of more than 8 dB. [ABSTRACT FROM AUTHOR]

This paper presents a 39-GHz broadband image-rejection down-conversion mixer for 5G millimeter-wave (mmWave) communication. To achieve a broadband image rejection, this paper proposes an on-chip compact transformer-based image-rejection filter, which exhibits the ability to track the pole and zero frequencies simultaneously. Moreover, the working mechanism and design guideline of the transformer-based image-rejection filter are illustrated with theoretical analysis, simulations and measurements. To enhance the mixer linearity performance, the transconductance stage of the conventional Gilbert mixer is utilized as a current source, and the radio frequency (RF) signal is directly fed into the switching stage. Fabricated in a 65-nm CMOS process, using a single-stage image-rejection filter with a compact area of only 0.013 mm2, the measurement results show that the proposed down-conversion mixer achieves a gain of 0 dB, a 3-dB RF bandwidth from 34 to 42 GHz, an input 1-dB compression point (IP 1dB) of 5.6 dBm, and an image rejection ratio (IRR) of about 25 dBc. [ABSTRACT FROM AUTHOR]

Carbon nanotube FET (CNFET) technology emerges as a promising replacement for MOS technology, offering novel circuit design capabilities with its multi-threshold voltage feature. This paper introduces a novel Schmitt trigger designed based on multi-threshold voltages, allowing direct and precise adjustments of VTL (lower threshold voltage) and VTH (higher threshold voltage) through two external control voltages. The VTL and VTH are nearly equal to these external voltages. These features result in the introduction of two new circuits for nanotechnology in this paper: the hardware implementation of the Hysteresis quantizer and the implementation of the voltage-to-period converter (V2P) circuit. Simulation results using Hspice software and the Stanford 32 nm library show that the proposed circuit exhibits considerable linear control ability, with a 49 % PDP improvement compared to other designs. Additionally, the first hardware implementation of the Hysteresis quantizer in nanoelectronics and the voltage-to-period converter demonstrate proper operation, marking a significant milestone. [ABSTRACT FROM AUTHOR]

Ad-hoc sensor networks (known also as citizen or resident networks) are gaining in popularity. They tend to utilize inexpensive sensors; they are deployed and operated in ad-hoc, opportunistic manner, consequently often delivering results of higher uncertainty. Reputation-based algorithms are used for data reconstruction to contain the input of faulty, or unreliable, nodes on the network. This paper discusses the question whether it is feasible to introduce high quality, expensive reference nodes to the network to significantly decrease its uncertainty, in situations where the reconstruction algorithm run by the network is not altered. This paper uses five leading cases, subsequently analyzed with the help of a simulator that executes the reputation-based EWMA algorithm. It identifies that the simple introduction of reference nodes alone does not help in addressing uncertainty without making alteration to the algorithm or to the design of the network. [ABSTRACT FROM AUTHOR]

This paper proposes a narrowband near-field (NF) source localization algorithm based on two correlation operations. By utilizing the correlation of incident signal in the time and spatial domains, the algorithm achieves direction-of-arrival (DOA) with high-precision and low-complexity and range estimation under the virtual single snapshot. To do so, in the processing of NF source received signals, this paper first utilizes the symmetry of the cross-cross array and obtains a covariance matrix containing only azimuth and elevation information through two correlation operations. Since the covariance matrix has a standard two-level Toeplitz matrix form, the estimated parameters can be directly extracted from the noise-free covariance matrix without pairing using the two-level Vandermonde decomposition technique. Finally, the estimated value of the range is obtained using a one-dimensional (1-D) spectral peak search. Computer simulation results verify the superior performance of the proposed algorithm in terms of complexity and estimation accuracy. [ABSTRACT FROM AUTHOR]

This paper discusses the synthesis of a steerable frequency-invariant radiation pattern for broadband scalable antenna arrays (SAAs). The proposed method allows to achieve constant beamwidth and beam direction over a 3 : 1 bandwidth and is based on an appropriate radiating elements' placement in the SAA and a proper amplitude and phase excitation of the array. Both amplitudes and phases of signals exciting the radiating elements are varied with frequency to ensure the radiation pattern invariance. Additionally, the paper proposes solutions to problems occurring in SAAs i.e., the problem of overlapping radiating elements and the problems of sidelobe and grating lobe reduction. To verify the proposed synthesis method, a set of radiating elements, which operate over a 3 − 9 GHz frequency range, has been manufactured and measured. The overall radiation pattern of the antenna array has been obtained by a summation of the radiation patterns produced by each of the radiating elements. • Synthesis of a steerable frequency-invariant radiation pattern. • Methods for grating lobe and side lobes reduction. • Solution to the overlapping radiating elements problem. [ABSTRACT FROM AUTHOR]

The sum rate maximization in multiuser MIMO broadcast channels is investigated in this paper. Due to the high computational complexity of non-linear dirty paper coding (DPC), zero-forcing dirty paper coding (ZF-DPC) is proposed as an alternative suboptimal approach. However, traditional ZF-DPC method requires that the number of total receive antennas is less than or equal to the number of transmit antennas. In this paper, we consider the scenario where the sum number of receive antennas may be more than the number of transmit antennas. It is shown that the optimal data stream allocation needs exhaustive search over all possibilities, and the complexity is significantly high. We propose a greedy transmit data allocation scheme that allocates one data stream at each step, the corresponding transmit beamforming vector and receive combining vector are designed to avoid interfering with the previous allocated data streams, and the pre-equalization Tomlinson–Harashima Precoder (THP) technique is adopted to pre-cancel the non-causally known interference caused by the previous allocated data streams. The proposed method is computationally efficient thanks to the low complexity. Simulation results show that this novel method outperforms the methods in the literature. [ABSTRACT FROM AUTHOR]

This paper presents the design of a self-image-guided ultrasonic (SIG-US) transceiver for reliable wireless power transmission (WPT) to miniaturized biomedical implants. In the receiver (RX) mode, this paper proposes a method for high precision time interval measurement (TIM) between two signals independent of their amplitudes. In the transmitter (TX) mode, a 15 V Class-DE driver by stacking 3.3 V transistors of 180 nm standard CMOS technology is designed to drive a 32-element linear array. The designed TX efficiency is 90.93%. The post-layout and the Matlab k-Wave toolbox simulation results show that the designed system is capable of transmitting power to the implant with less than 0.9% reduction compared to the ideal SIG-US system over the ± 45 ° steering range. Considering the mismatch effect between transistors, the power reduction is less than 2% in the worst case. The RX with a power consumption of 628.83 μ W from a nominal supply voltage of 1.8 V, is capable of detecting time delays between two signals over the input range of 1 mV to 10 mV, with high accuracy. [ABSTRACT FROM AUTHOR]

Single-phase string inverter has been widely applied to grid-tied photovoltaic (PV) rooftop applications for its renewable energy. However, the inherent attribute of intermittency in solar energy may induce instability and unqualified power. To meet the grid-interconnection standards, high demands of efficiency and harmonic distortion need to be imposed on DC/AC inverters. Conventional soft-switching inverters used to sacrificing auxiliary resonant circuits to exchange for soft switching. This requires additional costs as well as sufficient dead time to discharge junction capacitances of all switches, which exacerbates total harmonics distortion (THD) induced by dead-time effect. To improve, this paper proposes a partial soft-switching silicon carbide (SiC) -based active neutral-point-clamped (ANPC) inverter, which possesses high efficiency, eligible dead time, and no auxiliaries. 650-V SiC MOSFET is adopted for its smaller output capacitance compared with Si device. Hybrid PWM modulation is utilized to achieve partial soft switching. Whereas, the soft switching realization range and power losses highly depend on the dead time. To achieve less power loss and improved dead time effect, this paper proposes a loss model-based dead time algorithm through a Power Loss VS. Dead Time mathematical loss model. Moreover, the mechanism of the dead time affected by soft switching is explored. The transition modes, dead time configurable boundaries, and design procedure are also analyzed in detail. A 1-kW prototype is demonstrated with the input of 800 V and the rated output of 220 V/ 4.5 A. Its efficiency could reach 99.6% with THD=0.95% at full power level. [ABSTRACT FROM AUTHOR]

In a phase-locked loop (PLL), a high reset pulse width in the phase frequency detector (PFD) and current mismatches in the charge pump (CP) are the major contributors to a high reference spur in a clock. This paper presents a novel replica technique based dead zone free PFD to reduce the reset pulse and a self-cascode current-splitting CP to reduce current mismatch. The proposed PFD and CP are designed using the UMC 180 nm CMOS process. The proposed PFD achieves a reset pulse width of 113 ps. The CP is designed for a CP current of 100 μ A. It has an output voltage range of 0.4 V–1.2 V, with a current mismatch of 1.3%. A PLL with the proposed PFD+CP achieves a reference spur that is 39.5% lower than the reference spur of the PLL with conventional PFD+CP. The proposed PFD+CP consumes 0.28 mW power in the locked stated. The layout area consumed by the proposed PFD+CP is 46 × 75 μ m 2 . • The reference spur in a PLL is minimised in this paper. • The reset pulse width of the phase frequency detector (PFD) is reduced. • The current mismatch of the charge pump (CP) is decreased. • A novel replica technique based dead zone free PFD is proposed. • To reduce the reset pulse width of the PFD, replica technique is adopted. • A self-cascode current-splitting CP is proposed. • To reduce current mismatches in the CP, self-cascode current-splitting technique is used. [ABSTRACT FROM AUTHOR]

In this paper, to investigate the problem of radio wave propagation in complex environments, a new algorithm is proposed based on the equivalence principle algorithm and the domain decomposition method to rapidly and accurately predict electromagnetic scattering and radio wave propagation in half-space. First, equivalent surfaces are introduced to decompose the obstacle region and replace the scattering effect of obstacles within the equivalent surfaces with equivalent input and output electromagnetic currents. Then, the operator S, representing the relationship between the input and output equivalent electromagnetic currents on the equivalent surfaces, and the operator T, representing the interactions between the equivalent electromagnetic currents on each equivalent surface, are derived; this allows the calculation process of the overall spatial field in a complex environment to be simplified to the iterative calculation process of operators S and T. To reduce the complexity of calculating S, a neural network embedded with physical information is introduced to replace the calculation process. Finally, the training results are applied to an example and compared with the theoretical numerical results yielded by the method of moments in different cases with obstacles. The results reveal that the new method proposed in this paper is highly accurate and achieves a substantial improvement in calculation speed. Therefore, our proposed algorithm provides a new and reliable method for calculating the spatial field in complex environments. • The EPA is introduced to use equivalent surfaces to replace the scattering inside it. • The operators S and T are introduced into the process of solving the field. • A neural network with physical information embedded is applied to calculate the S. • Random undulating terrains are generated by Karhunen–Loève expansion. • MoM providing a good foundation for training is used to generate dataset. [ABSTRACT FROM AUTHOR]

As transistors shrink in size, the integration density of memory circuits like Static Random Access Memory (SRAM) cells rises, making them increasingly susceptible to Single Event Effects (SEE). In the space environment, memory circuits face stability and reliability challenges due to the presence of various charged particles such as α-particles, neutrons, electrons, heavy ions, and photons. These high-energy particles create ion tracks when they strike the memory device, leading to upsets in the storage bits. Conventional 6 T SRAM cells are susceptible to these upsets. As a solution this paper proposes a new Radiation Tolerable (RT 13 T) SRAM cell that is better suited for deep-space applications compared to other memory cell. RT13T has been validated to withstand radiation hazards through Critical Charge (Q Crit) analysis, which shows that it exhibits 1.17×, 1.1×, 1.94× and 1.06× highest Q Crit than QUCCE 10 T/12 T,traditional 6 T and LIOR 13 T memory cells, respectively. As the comparison made, our Proposed RT 13 T saved by5.1 %,9.9 %, 20.1 % and 7 % of the power consumption compared to QUCCE10T/12 T/LIOR 13 T/SERSC-16 T SRAM cells at a nominal supply voltage of 0.7 V. It also exhibits shorter read delay (T RA) 10.6 %, 1.34 %, 9.6 %, 22.16 %compared to QUCCE 10 T/12 T,6T, SERSC-16Tmemory cells, respectively. In terms of stability,our proposed RT13T SRAM cell exhibits 2.32×/2.05×/2.9×/1.05×/1.01 × higher read stability as compared with QUCCE10T/12 T/6T/LIOR 13 T/SERSC-16 T memory cells during the read operation. The our proposed RT13T shows improvements in design metrics are at the expense of a longer write delay. To characterize the performances of the proposed RT13T, 16-nm CMOS predictive technology model and validated through extensive simulation with licensed PrimeSim HSPICE of Synopsys. The results of our proposed RT13T cell are compared with some other previously proposed memory cells such as 6 T, QUCCE 10 T, QUCCE 12 T, LIOR 13 T and SERSC-16 T memory cells. The obtained results are tabulated and plotted for graphical analysis. In terms of area consumption our proposed 13 T consumes 0.9×/0.6 × lesser area than QUCCE 12 T/SERSC-16 T memory cells but our proposed circuit consumes 3.1×/1.08×/1.05 × more area than QUCCE10T/conventional 6 T/LIOR 13 T because QUCCE10T and 6 T consist of less number of transistors in memory cells.The cell proposed in this paper demonstrates strong radiation-hardened capabilities and excellent overall performance, making it well-suited for aerospace electronic devices and ensuring stable operation in space radiation environments. [ABSTRACT FROM AUTHOR]

This paper presents and compares the implementation of a digital predistortion (DPD) linearizer for radiofrequency power amplifiers (PAs) considering two different hardware acceleration platforms. Both graphics processing unit (GPU)-based and field programmable gate arrays (FPGA)-based implementations of the DPD are capable to meet the high throughput requirements for linearizing the PA with current 5G new radio (NR) wideband signals. A comparison in terms of hardware resources usage, precision, throughput and linearization performance is provided for both GPU and FPGA implementations of a DPD based on the generalized memory polynomial (GMP) behavioral model. [Display omitted] • This paper focuses on the implementation of the GMP DPD model in both FPGA and GPU. • A trade-off among precision, resources usage and throughput performance is given. • The DPD performance is validated with a SLMBA with a hardware-in-loop test setup. [ABSTRACT FROM AUTHOR]

The problem addressed in this work is the enhancement of energy efficiency in buildings, primarily focused on heating control. The paper highlights the importance of addressing this challenge, given that HVAC systems are responsible for over 60% of total energy consumption in buildings, making them the largest energy consumers in both the residential and nonresidential sectors. This paper presents a methodology for developing a model predictive control (MPC) system based on artificial neural network (ANN) models, with the aim of improving the energy efficiency of buildings. This approach involves the creation of a training dataset using dynamic thermal simulation tools, enabling the learning of the ANN model that is responsible for predicting future states within an MPC optimization loop. Additionally, the implementation leverages advanced technologies such as Field-Programmable Gate Arrays (FPGAs), specifically the PYNQ board, Wi-Fi modules, and MQTT communication to enhance scalability, deployment, and adaptability. The study evaluates the proposed Neural Network Model Predictive Control (NNMPC) strategy implemented on the PYNQ, reporting a substantial reduction of 38.53% in heating energy consumption in buildings compared to a basic On/Off control approach for 24-hour simulation. This outcome underscores the solutions significant potential for energy savings in building heating systems. [ABSTRACT FROM AUTHOR]

To address the problem of obstacles blocking wireless channels and increase the transmission rate of unmanned aerial vehicle (UAV) communication systems, this paper proposes a method for maximizing the system sum rate in downlink communication networks based on intelligent reflecting surface (IRS)-assisted UAV. First, we lead into non orthogonal multiple access (NOMA) technology. Second, the system sum rate is maximized by jointly optimizing the IRS phase shift, 3D UAV trajectory, user scheduling and power allocation. Since the coupling and non-convexity of optimization variables make this problem difficult to solve directly, the original nonconvex problem is converted into four subproblems through block coordinate descent (BCD). Then, the subproblems are solved alternately using methods, such as semi-definite relaxation technique (SDR), relaxation variable introduction, successive convex approximation (SCA), the Lagrange multiplier method and first-order Taylor expansion. The results show that the algorithm proposed in this paper substantially improves the system sum rate and has favorable convergence. [ABSTRACT FROM AUTHOR]

With the increasing number of users accessing the Internet over 5G systems, security concerns have become a major challenge that needs to be addressed. This paper proposes a solution to this challenge by proposing a system to train defenders to handle cyber attacks and develop intrusion detection systems that can timely notify of security events, also within the 5G core itself. This paper builds on our previous contributions on a containerized 5G testbed and proposes a novel set of full-stack attacks targeting networked hosts and 5G Network Functions (NFs) alike. Importantly, we identify the potential to generate persistent Packet Forwarding and Control Protocol (PFCP) Denial of Service (DoS) attacks to deprive end users of connectivity to the data network, even in the event of a handover to another gNodeB. This framework is envisaged to facilitate the generation of highly diverse and realistic datasets, containing malicious GPRS Tunneling Protocol (GTP) and PFCP traffic captured over 5G interfaces, thereby enhancing the security of next-generation networks. [ABSTRACT FROM AUTHOR]

This paper presents a fully-digital background calibration method for calibrating timing mismatch in dual-channel time-interleaved analog-to-digital converter (TIADC). The proposed method estimates timing mismatch by performing correlation calculations on the outputs of sub-channels and corrects this mismatch using the improved perfect reconstruction filter bank (PRFB). The PRFB, which is improved by employing a polynomial fitting method, offers superior performance with fewer filter taps and extends the timing mismatch correction capability to almost the entire sampling clock cycle. The improved PRFB uses only one twentieth of the taps used in the original PRFB, and its dual-channel FIR filters have anti-symmetric taps. To enhance the real-time calibration capability of the system, this paper gives a fully-parallel hardware structure for calibrating offset, gain, bandwidth, and timing mismatches. The effectiveness of the proposed hardware structure is verified through a 10-bit 3GS/s dual-channel TIADC test platform. Simulation and measurement results show that the proposed calibration method significantly improves the signal-to-noise-and-distortion (SNDR) and spurious-free dynamic range (SFDR) of both single-tone and multi-tone input signals, which makes the proposed method a viable solution for practical TIADC applications. [ABSTRACT FROM AUTHOR]

Accurately locating an indoor unknown radio emitter (URE) is a challenging target to ensure telecommunication security. The URE positioning method based on received signal strength difference (RSSD) has attracted considerable attention due to the advantage of not being affected by transmit power and frequency. However, the RSSD-based fingerprint technique cannot accurately express the constraint equations between signal characteristics and geographic coordinates because of redundant databases and false matching. In this paper, a novel RSSD-based indoor positioning method using factor graph (FG) for an URE is proposed to improve positioning accuracy and reduce computational complexity. Firstly, the databases are reconstructed by singular value decomposition (SVD) to eliminate redundant factor nodes. Secondly, Pearson correlation coefficient (PCC) is utilized to determine the sub-positioning area. Combing SVD with PCC, the hyperplane equations are reconstructed to build an optimized FG model, called SP-FG. Considering simulation and experiment, the proposed SP-FG algorithm improves the cumulative distribution function (CDF) of average positioning error within 0.5 m by 10% and 14% compared with conventional FG algorithm and K-nearest neighbor (KNN) algorithm, respectively. In addition, this paper discusses the superiority of proposed SP-FG algorithm in positioning accuracy under different reference side lengths, access point (AP) coordinates and numbers. [ABSTRACT FROM AUTHOR]

A recent study has revealed that incorporating intelligent reflecting surfaces (IRS) into wireless systems improves their performance within various signal propagation conditions. This research paper focuses on evaluating the spectrum-sensing abilities of cognitive radio in wireless environments enhanced by IRS technology. To achieve this, the paper develops a statistical model to describe the connections between the primary user (PU) and IRS, as well as between IRS and the secondary user (SU). This model calculates a precise approximation of the probability density function (PDF) of the end-to-end instantaneous signal-to-noise ratio (SNR). The SNR considers both the PU-to-IRS link, which follows a Rayleigh fading distribution, and the IRS-to-SU link, which follows an FTR fading distribution. By utilizing this PDF distribution, the paper derives analytical expressions for the average probability of detection (APD) for single and cooperative secondary users. These APD expressions are then employed to establish the exact closed-form expression for the average area under the receiver operating characteristics (AUC), system throughput, and transmission probability of the SU. To validate these theoretical findings, the paper conducts Monte Carlo simulations. The results from these simulations indicate an improved detection probability when operating in an IRS-enhanced wireless propagation environment. Consequently, the study suggests that incorporating IRS technology can significantly enhance the reliability of communication systems based on cognitive radio principles. [ABSTRACT FROM AUTHOR]

In this paper a novel reconfigurable H-plane horn Multiple Input Multiple Output (MIMO) leaky wave substrate integrated waveguide (SIW) antenna is proposed. The antenna is operating at two resonant frequencies, 22.8 GHz and 26.32 GHz. The transverse periodic leaky wave slots are radiating power in the broadside direction at 22.8 GHz and pattern diversity is achieved at 26.32 GHz. Dielectric loading and an array of meta -material structures are used, which further improve gain of the antenna. The antenna achieves better matching with a return loss of –33.5 dB at 22.8 GHz and maximum isolation of −38.7 dB at 26.32 GHz is achieved between antenna elements. A 2x2 and 4x4 MIMO SIW antenna is designed and analyzed in this paper. All the MIMO performance measurement parameters have values within limits. The antenna achieves a maximum gain of 7.3 dBi and 8.1 dBi. The proposed antenna operates in the K band (18 GHz–27 GHz) region, making it suitable for automotive radars and short-range applications. [ABSTRACT FROM AUTHOR]

The performance dependence of a single-turn octagonal inductor on its guard ring spacing at millimeter-wave (mm-wave) and sub-THz frequencies is investigated in this paper. The typical range of inductance that is employed in RFIC circuit designs at these frequencies is in the order of a few tens to a few hundreds of picohenries (p H). This paper shows that for such inductors at mm-wave/sub-THz frequencies, the quality factor (Q) is affected by the spacing of the guard ring (S g) around it. At certain frequencies the Q sharply drops. This behavior is not typically seen at lower GHz-range frequencies and hence the guard ring design has not been critically studied. The coupling between the inductor and the guard ring surrounding it is observed to have magnetic resonant behavior and hence results in sharp reduction in Q at certain frequencies. The observed phenomenon is correlated to the theoretical framework developed for understanding this phenomenon including model and necessary equations. The dependence of quality factor on the guard ring current is modeled. An empirical model is also proposed to identify the frequency at which the sharp reduction in Q occurs. The impact of S g on the inductors is relatively less pronounced for large-sized inductors. The Inductance (L) and Self Resonant Frequency (f S R) are shown to remain unaffected with changes in guard ring spacing. Guidelines, along with an example, are provided for determining optimal guard ring spacing for inductors operating at millimeter-wave/sub-THz frequencies. [ABSTRACT FROM AUTHOR]

This paper presents a novel class-C VCO by exploiting a capacitive transformer-based (CT-based) resonator. Assuming the same Q-factor, the CT-based resonator has a lower equivalent resistance than the conventional LC resonator, which results in reduction of the phase noise. Moreover, using the second node of resonator for biasing core transistors' gates enhances the loop gain and provides a robust start-up for biasing MOS gates of the active pair. Furthermore, compared to the conventional oscillator, a larger tail capacitance can be used in the proposed class-C oscillator, which results in greater phase noise improvement. Additionally, the oscillation amplitude calculated accurately in this paper demonstrates that using the CT-based resonator negligibly affects the maximum oscillation amplitude in the CMOS class-C oscillator in the deep-submicron processes. The proposed oscillator is implemented in standard 90-nm CMOS technology and operates at 3.5–3.7 GHz. Its phase noise at 1 MHz and 3 MHz offset frequencies are −129 dBc/Hz and −138.4 dBc/Hz in 3.6 GHz, respectively. The proposed structure occupies 0.49 mm 2 core area and consumes 9.2 mW power with the FoM 190.3 dBc/Hz at 3 MHz offset frequency. [ABSTRACT FROM AUTHOR]

• Proposes an innovative orthogonal autocorrelation radiometer architecture based on Hilbert transform theory. • The harmonic balance method and envelope method are combined to solve the mathematical model of the architecture. • The test results show that the autocorrelation radiometer is much better than the full-power radiometer in terms of temperature sensitivity and detection sensitivity. • The digital integration algorithm is introduced to process the output voltage value, and the average error of the radiometer for testing the temperature is only 0.034℃. In this paper, to solve the problem that the square-law baud detection in traditional full power radiometers restricts their sensitivity performance, inspired by the complex correlation algorithm and the Hilbert transformation, an innovative orthogonal autocorrelation microwave radiometer architecture is proposed. This paper solves the mathematical relationship between the additional error of the architecture unit and the temperature measurement sensitivity by establishing the mathematical model of the architecture and using the harmonic balance and the envelope method simulation plugins in ADS.The sensitivity of the autocorrelation architecture is less affected by the additional amplitude error, and the detection accuracy of it is higher when the additional phase and amplitude errors exist. Through the comparison of the two architectures in 12–14 GHz, the test results show that the autocorrelation radiometer is much better than the full power radiometer in temperature sensitivity and detection sensitivity. The temperature of human palm was tested in laboratory environment using the radiometer engineering prototype. To solve the problem of large fluctuations in the output voltage value of the radiometer, a digital integration algorithm is introduced to process the output voltage value. The average error of the radiometer for measuring temperature is decreased from 0.19 °C to 0.034 °C. [ABSTRACT FROM AUTHOR]

Mood, as a common psychological activity, has a significant regulatory effect on memory formation. However, the fact that mood coexists with memory is rarely taken into account in memristive neural networks. In this paper, a memristive circuit that combines mood and memory is designed to implement of mood-dependent memory. The circuit mainly comprises three types of modules: the memory module, the mood module, and the mood-dependent module. It demonstrates and verifies mood-dependent memory by combining the memory module with the mood model, and realizes the regulation of mood on the rate of memory formation by the mood-dependent module. This paper also discusses and implements a non-linear learning curve on the basis of mood-dependent memory. The effectiveness of the proposed circuit is demonstrated by simulation results in Pspice. The memristive circuit design of mood-dependent memory with a learning curve can provide more references for the application of memristors. [ABSTRACT FROM AUTHOR]

This paper introduces a new design of a quadrature 3-dB power splitter using a quadrature Wilkinson power divider and a cross-type short-circuited shunt stub for printed circuit board (PCB) circuit design. For 3-dB power splitting and a relative 90° phase difference, several types of quadrature 3-dB power splitters are commonly used in RF and microwave applications, including Lange coupler, directional coupler, branch-line coupler, and quadrature Wilkinson power dividers. Among them, quadrature Wilkinson power dividers often utilize a Schiffman phase shifter and λ/4 short-circuited shunt stubs for compensation circuit. In this paper, the aforementioned schemes have been evaluated by image rejection ratio (IRR) bandwidth (BW) related to amplitude and phase imbalance property. The new design of the quadrature Wilkinson power divider adopting the proposed cross-type short-circuited shunt stub offers superior −25-dB IRR BW compared with other quadrature 3-dB power splitters in PCB fabrication. In measurement, the proposed quadrature Wilkinson power divider provided a −25-dB IRR BW of 3.50 GHz, operating at a center frequency of 9.5 GHz. The designed power splitter offered an operating frequency of 2.64 GHz, satisfying −25-dB IRR BW, 10-dB impedance BWs, and 20-dB isolation BW. [ABSTRACT FROM AUTHOR]

The traditional mirror current source circuit has been widely used in analog circuits. However, the output current of this circuit is not adjustable after the circuit is manufactured, which is a difficult issues. To solve this problem, this paper proposes a memristive continuously adjustable cascode current source. In this paper, we introduce two additional MOS transistors and a memristor to the circuit architecture of the cascode current mirror. This modified design achieves electrical isolation between the improved cascode current source and the memristor control circuit. By incorporating a memristor control circuit, we are able to regulate the memristance in the main circuit, which in turn allows for continuously adjustable output current. The mathematical relationship between the control signal and the output current of the memristor control circuit is derived in this paper, and the mathematical model is verified using PSPICE. The simulation results show that the continuously adjustable cascode current source based on the memristor achieves continuous regulation of the output current and high accuracy of the output current. This paper provides a technical solution to the problem that the traditional current source circuit cannot realize the continuous adjustable output current. [ABSTRACT FROM AUTHOR]

This paper presents a flexible and wearable (on-body) dual band antenna operating in two Industrial, Scientific and Medical (ISM) frequency bands. The central frequencies selected are equal to 2.45 GHz and 5.8 GHz. In order to make the antenna suitable for Wireless Body Area Network (WBAN) applications, it is fabricated on a flexible biopolymer called cellulose laurate (CL). The proposed antenna, that has been designed and optimized on ANSYS HFSS, is realized using a process based on copper adhesive tape and laser structuring. The characterization of the antenna in terms of reflection coefficient, gain and radiation patterns shows a good agreement with the simulation data. Compared to state-of-the-art antennas, the investigated solution demonstrates competitive results. The proposed antenna also features stable performance under bending conditions and the estimated specific absorption rate (SAR) is well below the limits defined by international standards. All these results suggest that the proposed antenna is very well suited for potential wearable applications and is a step towards fully green electronics. [ABSTRACT FROM AUTHOR]

Composed of an inflated cavity and helical radiator made of PVC films and conductive tape, a proof of concept of the inflatable axial-mode helical antenna with retractability and releasability to replace the standard complicated antenna structure with the same size is, optimized, fabricated, and tested in this paper. Using flexible material to build inflatable antenna not only reduces the volume and weight itself, for the height and weight of folded antenna are equivalent to 4.7% and 1.6% of those of rigid antenna with the same size, respectively, but also lowers the manufacturing cost significantly, which is less than 2% of the price of mechanically deployable antenna. According to the experimental results, the −10 dB impedance bandwidth of the proposed antenna can cover 1.38–2.03 GHz (38.1%), and the 3 dB AR bandwidth covers 1.1–2.12 GHz (63.4%). As for the peak gain, it is 11.78 dBic at 1.7 GHz. Besides, the signal of the inflatable axial-mode helical antenna can be detected by 11 satellites, obtaining a satisfying positioning message. Therefore, the inflatable axial-mode helical antenna has broad prospects in emergency communication, military operations, and other fields to provide with satellite navigation and positioning message. [ABSTRACT FROM AUTHOR]

This paper describes the optimal design and analysis of compact multiband Hybrid Fractal Antenna using Invasive Weed Optimization (HFAIWO). The configured structure involves the fusion of Minkowski, Sierpinski carpet and Giuseppe Peano in a coherent manner. The two-iterative conglomerated fractal antenna is realized physically by considering FR4 epoxy material (dielectric constant, ε r = 4.4 and mass density = 1,900 kg/m3). The volumetric dimensions of the fabricated prototype are 36 x 36 x 1.6 mm3. In the designing process, the geometrical descriptors, namely, feedline width 'W F ' and ground plane dimension 'L G ' are optimized specifically using Invasive Weed Optimization (IWO) and Harmony Search Algorithm (HSA) strategies. The optimal solution is searched by changing the descriptor values under a set of practical constraints. The examined values of 'W F ' and 'L G ' using IWO and HSA are 3 and 31 mm, and 2.6 and 28.7 mm, respectively. Comparative results reveal that IWO offers superior solution quality and convergence than HSA. Afterwards, experimentation of the Projected HFAIWO is done to justify the recommended fractal hybridization approach. Measurements reveal that for VSWR ≤ 2, the fabricated structure produces nine resonance points (1.84, 3.99, 5.15, 5.55, 6.30, 6.58, 8.00, 9.29, and 12.01 GHz) with appreciable gain values. At the respective resonance points, the −10 dB impedance bandwidth is 3.9 %, 3.1 %, 2.1 %, 2.2 %, 1.4 %, 1.2 %, 6.9 %, 1.2 %, and 12.23 %. The provided radiation patterns are arbitrary bidirectional/omnidirectional. By applying the above-said approaches, the radiator size is reduced by 54 %. Importantly, the constructed structure covers two important bands i.e. 1.84 GHz (GSM 1800 band, downlink) and 5.55 GHz (WLAN (Lower) 5.150–5.725 GHz) associated with energy harvesting applications. The practical outcomes suggest that the introduced prototype is a proficient candidate for energy harvesting systems, Satellite communication for downlink, Long range tracking, Battlefield surveillance, Digital broadcast satellite service, Weather Radar, and Maritime navigation radar. [ABSTRACT FROM AUTHOR]

This paper presents an LDO design tailored to the various power domains of CPUs. In contemporary CPU designs, different functional modules typically necessitate distinct voltage levels, thus requiring a flexible and adjustable power management approach. An LDO with an internally compensated super source follower (SSF) and a multi-zero-pole compensated loop stability is proposed. The SSF is used to reduce the output impedance of the LDO, enhancing its carry-under-load capability. The loop is then transformed into a multi-zero-pole system through Miller compensation, feed-forward compensation, and zero-pole tracking compensation techniques, enabling the LDO to achieve stability and reliability under different loads. The LDO proposed in this study was designed using a 110 nm CMOS process. The LDO can operate within a temperature range of −40–150 °C, with a low quiescent current of 57 μA. The power supply rejection ratio of the circuit is −22 dB at 1 MHz. When the load current jumps from 5 mA to 300 mA within 40 μs, the output voltage experiences an undershoot of 271 mV, an overshoot of 174 mV, and a maximum adjustment time of 100 μs. The load regulation is 0.00267 mV/mA, and the line regulation is 1 mV/V. [ABSTRACT FROM AUTHOR]

This paper presents a novel multibeam filtering antenna array based on a compact 3 × 3 Nolen matrix integrated with HRR filters for solar observations. The design facilitates the simultaneous recording of solar radio flux density and sky background flux density, streamlining calibration processes. The use of stub-loaded transmission line (SLTL) couplers achieves a significant 43.4% reduction in the size of the Nolen matrix, enhancing compactness. The hairpin ring resonator (HRR) filter with two transmission zeros (TZs) is employed to ensure electromagnetic compatibility (EMC). Given the limitations of conventional manual design methods, the intelligent grey wolf algorithm (GWA) is adopted to optimize the physical parameters of the Nolen matrix layout, realizing rapid and accurate achievement of the desired performance. The − 6. 2 ± 0. 15 dB transmission coefficient and 0°, −120°and + 120 °of output phase differences within 2° phase error are accomplished at 2.8 GHz. Finally, the proposed multibeam filtering antenna array is fabricated and measured to confirm its ability to generate the required three beams with filtering characteristics. The measured results have a good agreement with the simulated results. [ABSTRACT FROM AUTHOR]

In this paper, a miniaturized dual-band frequency selective surface (FSS) for electromagnetic shielding applications is presented. The FSS unit cell provides band-stop response at the resonant frequencies of 0.95 GHz and 2.52 GHz. The FSS element is constructed by employing convoluted metal stripes that are positioned on both sides of the substrate. The proposed configuration enhances the electrical length of the resonator while maintaining its physical dimensions. Moreover, the unit cell of the FSS exhibits rotational symmetry, which enables polarization independent operation. The designed FSS structure demonstrates excellent miniaturization characteristics, with a cell size and thickness of 0.019 λ 0 × 0.019 λ 0 , and 0.00048 λ 0 , respectively. The cell size and thickness are calculated at the lower resonating frequency of 0.95 GHz. In addition, the stability of the proposed FSS structure is observed for both the TE and TM polarizations across an incident angle range of 0° to 80°. The resonating behavior of the structure is elucidated with the help of electric field and surface current distribution. Experimental verification of the dual-band FSS is conducted through the fabrication of a prototype on a FR4 substrate. The measured transmission coefficients are in good agreement with the simulated response for both TE and TM modes. Compared with the dual-band FSSs previously reported, the proposed FSS has the significant advantages of low profile and miniaturization. [ABSTRACT FROM AUTHOR]

Maximal ratio combining (MRC) and selection combining (SC) diversity techniques enhance wireless communication networks' reliability by mitigating fading effects and improving the signal-to-noise ratio (SNR) at the receiver. Hence, these techniques have a crucial impact on reducing the bit error rate (BER) and increasing the capacity of wireless communication systems. This paper introduces new exact mathematical formulas for the distribution of instantaneous SNR, BER and channel capacity per unit bandwidth (CpUB) for L-branch MRC and SC diversity receivers in offset quadrature amplitude modulation-based filter bank multi-carrier (OQAM/FBMC) systems for 5G wireless communication. Additionally, new formulations for BER and CpUB using the semi-analytical method have been derived. These formulas consider the combined effects of non-linear distortion from a high-power amplifier (NLD-HPA), the Rayleigh fading channel, and impulsive noise (IN). Monte-Carlo computer simulations verify the validity and accuracy of the derived theoretical instantaneous SNR, BER and CpUB across OQAM/FBMC-MRC and OQAM/FBMC-SC diversity system parameters, such as the number of branches (L), the input back-off (IBO) of NLD-HPA, and IN. According to the results of simulation modeling and a comparative analysis of performance, the OQAM/FBMC-MRC diversity system tends to have better BER performance and CpUB compared to the OQAM/FBMA-SC system in all scenarios. [ABSTRACT FROM AUTHOR]

The Intelligent reflecting surfaces (IRSs) have been established to show the capability to enhance spectral and energy efficiency by using the passive beamforming at the IRS point and joint optimization of the active beamforming at the base station (BS). However, in the smart wireless environments in which mostly passive RISs are deplored the estimation of the channel state estimation is challenging. This paper, therefore, aims to propose a channel estimation scheme with an improved performance in comparison with some other recently proposed estimation schemes. The proposed channel estimation scheme employs the hybrid strategy to combine the improved versions of traditional Orthogonal Matching Pursuit (OMP) and Subspace Pursuit (SP) compressive sensing algorithms as a basis for the proposed estimator. The proposed estimator, through computer simulations, shows improved performance when compared with the other four channel estimators that were recently documented in literature though with a slightly high computational complexity cost. [ABSTRACT FROM AUTHOR]

This paper examines a short-range Millimeter-wave antenna characterized by its compact design, coplanar waveguide feeding, and folded dipole shape, that operates across multiple frequency spectrums. The radiator is designed on a Rogers TMM4 material having the dimensions of 1.05 λ L × 1.05 λ L × 0.057 λ L (λ L : wavelength associated with the bottommost cut-off frequency). Adoption of a folded shape serves to augment the electrical dimension of the antenna by expanding the current-carrying path, thereby facilitating the attainment of the necessary frequency spectrums. The proposed antenna operates at 22.44–23.77 GHz (5.75 %), 26.68–30.35 GHz (12.87 %), 38.1–43.46 GHz (13.14 %), 49.13–54.48 GHz (10.33 %) and 57.63–67.85 GHz (16.29 %) spectrums with maximum gain and radiation efficiency of 8dBi and 94.5 % respectively. The work further delves into an in-depth analysis of antenna characteristics, encompassing aspects such as radiation pattern, surface current, group delay, and transfer function. All examined characteristics affirm that the proposed antenna exhibits versatility for diverse frequency bands, including but not limited to n257, n259, n260, n261, and various other 5G/beyond 5G wireless technologies. [ABSTRACT FROM AUTHOR]

This paper presents an automatic tuning method based on a stepping search algorithm for bandpass cavity filters. This method imitates human tuning manipulation without recourse to a theoretical model of filter. To a certain extent, this implementation can replace and optimize the tuning work rely on engineers' experience. The return loss and insert loss are the key indexes to measure whether the tuning terminated, and the hierarchical optimization objectives used as evaluation function of the method. To verify this approach, two screw- tuned cavity filters tuning instance are given with five screws and eleven screws respectively. [ABSTRACT FROM AUTHOR]

In this paper, a circularly polarized rectenna is proposed for microwave energy transmission, which is composed of a broadband Substrate Integrated Waveguide (SIW) antenna and a rectifier circuit. A dielectric resonator is loaded on the SIW antenna, enhancing the impedance bandwidth. Circular polarization is achieved by chamfering the diagonal of the rectangular patch. Two sections of microstrip branches are employed for good impedance matching over the broadband operation. Measured results show that the proposed rectenna has a good impedance performance (|S 11 | < −10 dB) and high RF-DC conversion efficiency (>50 %) over a relative bandwidth of 22.9 % (29–36.5 GHz). The maximum conversion efficiency of 67.5 % is realized at the input power of 18 dBm. [ABSTRACT FROM AUTHOR]

This paper presents a new proximity-coupling mechanism between a rectangular patch and a microstrip line with an open circuit terminal. The patch is located to cover both adjacent maximum-voltage (capacitive coupling) and maximum-current (inductive coupling) points of the standing wave on the feedline, and consequently, two orthogonal resonant modes with 90° phase difference are excited on the patch for generating a circularly polarized (CP) radiation. Based on this feeding mechanism, a dual-band dual-sense CP antenna is designed, which is composed of two linear rectangular patch arrays coupled to an open-ending microstrip line. It is realized on a single-layer substrate and its CP rotating sense in each band is opposite to each other. For verification, the antenna operating at 5.0 and 8.0 GHz are designed, fabricated, and tested. Noting that the design concept can be easily implemented to other frequency bands. The measurements result in an impedance-matching bandwidth of 4.72 – 5.10 GHz and 7.50 – 8.20 GHz. The antenna is left-hand CP for the lower band and right-hand CP for the upper band. In addition, the prototype shows a 3-dB axial ratio bandwidth of 4.93 – 5.02 GHz and 7.40 – 8.10 GHz and peak gains of 11.4 and 12.7 dBic at the lower and upper bands, respectively. [ABSTRACT FROM AUTHOR]

This paper presents a reconfigurable bandstop frequency selective surface (R-FSS) design capable of switching across C, X and Ku-bands. The electronic switching mechanism is achieved in real-time through PIN diodes. The combination of rectangular loops is selected as unit-cell and PIN diodes are strategically placed to dynamically adjust the bandstop region. The device operates in three distinct modes corresponding to the activation status of the PIN-diodes. For TE polarization, Mode 1 encompasses the Ku-bandstop (12.64–14.75 GHz), Mode 2 corresponds to the C/X-bandstop (6.62–11.28 GHz), and Mode 3 involves the X-bandstop (9.82–11.63 GHz), whereas X-bandstop characteristic is observed for TM polarization (9.054–––11.29 GHz). In TE polarization, each configuration is defined by specific equivalent circuit models, featuring an inductance in parallel with series L-C resonant circuit, an L-C resonant circuit in parallel with the inductance, and two L-C resonant circuits in parallel, respectively. Additionally, for TM polarization, the configuration incorporates two parallel L-C resonant circuits. A prototype of the proposed R-FSS is fabricated and measured. The results demonstrated effective switching operation across the C, X and Ku-band stopbands, depending on the biasing of the PIN diodes. The experimental outcomes are consistent with the simulation results, affirming the compatibility and functionality of the proposed R-FSS design. [ABSTRACT FROM AUTHOR]

This paper presents a W-band stable high gain 2 × 2 cavity-backed slot antenna array fed by compact high-order mode substrate-integrated cavity (SIC) with substrate-integrated waveguide (SIW) technology. The antenna element incorporates a 2 × 2 subarray of cross-shaped slots, excited by a high-order mode (TE 220) SIC, ensuring uniform amplitude and balanced phase to achieve stable high-gain and high efficiency. Moreover, an additional SIW cavity is stacked above the 2 × 2 cross-shaped slots, incorporating a rectangular slot etched on the surface of the SIW cavity for radiation to further enhance the gain. This novel architecture yields a gain enhancement of 2.6 dBi compared to the traditional unstacked SIW cavity antenna. A prototype antenna array, consisting of 2 × 2 radiation elements and a low-loss 1-to-4 SIW power divider integrated with waveguide (WG) to SIW transition, is designed and fabricated in standard PCB technology. The measured results exhibit a −10 dB impedance bandwidth range from 91 to 97 GHz, a peak gain of 18.5 dBi, and a peak aperture efficiency of up to 78 %. [ABSTRACT FROM AUTHOR]

This paper presents a wideband and high-fundamental rejection self-mixing frequency tripler in a 40-nm CMOS. The proposed tripler consists of an input half-shielded transformer balun, an even-harmonics generator, a single-balanced mixer, a slow-wave coupling-line filter and an output half-shielded Marchand balun. The half-shielded coupling structure improves the coupling coefficient of the coupling-line components and also features high design freedom. Consequently, the half-shielded transformer balun achieves a broadband performance. The half-shielded Marchand balun achieves a 1-dB bandwidth of 109 GHz (49.7 %) and a minimum insertion loss of 1 dB. The slow-wave coupling-line filter enhances the fundamental rejection of the proposed tripler with low insertion loss of 1.5 dB, wide 1-dB bandwidth of 162 GHz (62.8 %) and compact footprint (0.01 mm2, 0.00535 λ2). The slow-wave coupling-line filter achieves a broadband low-frequency rejection over 18.6 dB from 65 to 88 GHz. Due to the above-mentioned technology, the tripler achieves a 3-dB bandwidth of 49 GHz from 195 to 244 GHz and a fundamental rejection larger than 23 dBc. Compared with the state-of-the-arts, the proposed self-mixing tripler features wide bandwidth, high fundamental rejection and compact core area among silicon-based triplers. [ABSTRACT FROM AUTHOR]

The energy of Wireless Sensor Network (WSN) in edge network is limited. In order to save energy, data bundling is proposed to reduce the energy consumed in setting up connection links by joining several packets into a single unit. However, although current data bundling schemes can reduce energy consumption, they will increase the delay of data routing, so it makes the multi-hop end to end delay a lot in WSN. Also, there is no appropriate solution to tackle the delayed growing problem caused by data bundling. And the energy consumption of the Acknowledgment (ACK) transmission is not comprehensively considered either. Regarding to those issues of previous researches, in this paper, a Data and ACK Bundling Scheme (DAB) is proposed to aggregate several data or ACK packets into a single unit to reduce the energy consumption as well as the end to end delay of the WSN. In the proposed DAB scheme, not only multiple packets but also ACK bundling into a single unit can reduce energy consumption. More importantly, the parameters of bundling technology are optimized from a global perspective in DAB scheme, so that WSN can not only improve the network lifetime, but also reduce the end to end delay which is impossible in previous studies. The theoretical analysis and experimental results illustrate that, while ensuring the reliability of data collection, our DAB scheme improves the energy efficiency by 29.03 % and reduces the delay by 22.29 % when compared with our traditional data collection scheme. [ABSTRACT FROM AUTHOR]