Electronics Letters最新文献

Static and dynamic characteristics of a quantum dot (QD) laser with double asymmetric barrier layers – an advanced type of semiconductor laser – are studied. Both direct and indirect capture of carriers into the lasing ground state in QDs is considered. The intradot relaxation of carriers, which controls the laser characteristics in the case of only indirect capture, is shown to not be a significant factor in the case of both direct and indirect capture. In the latter case, both the output optical power and modulation bandwidth are considerably increased.

This work reports a W-band 2-stage stacked LNA featuring post-distortion non-linearity cancellation (PDC) with programmable gain and enhanced common-mode (CM) stability, fabricated in TSMC 28-nm complementary metal oxide semiconductor (CMOS). The PDC technique employs diode-connected NMOS transistors to enhance linearity. The diodes are connected to drains of the stage one and, therefore, are isolated from the input, leading to minimal impact on input matching. Since the diodes are in strong inversion, they track well with the main transistors, resulting in robust cancellation across PVT. Additionally, the diodes also enhance the CM stability of the LNA by reducing the CM gain. Use of stacked architecture lowers the DC power consumption, through current re-use in the two stages. Switchable neutralized differential pair cells are used in stage one to achieve variable gain. The LNA consumes 31 mW of power with an IP1dB of -5.5 dBm and IIP3 of 6 dBm leading to an figure-of-merit (FOM) of 31.3 dB. The peak gain is 13 dB at 84.2 GHz, and it maintains $�>$5 dB gain between 75 and 95 GHz. The LNA has 2.7 dB of programmable gain control. The minimum measured NF is 6.78 dB at 89.4 GHz. The proposed LNA is suitable for high-linearity receivers for automotive radar and 6G applications.

This study proposes a voltage-retention circuit (VRC) for a low-power phase-locked loop (PLL) designed for mobile interfaces. The PLL, incorporating the proposed scheme, supports the sleep mode to achieve low power consumption and fast switching between the sleep and active modes. To facilitate rapid switching between these modes, the proposed VRC stores the filter information from the previous input during sleep mode, ensuring quick settling upon reactivation. The VRC comprises a resistor-steering digital-to-analog converter (DAC), a comparator, and a counter. During the active mode, the circuit adjusts the DAC using the comparator and counter to track the loop-filter voltage, and it holds the tracked voltage value during the sleep mode. The proposed circuit, designed using a 65-nm CMOS process, demonstrates 54% improved settling time compared to conventional circuits. Additionally, it reduces power consumption during sleep mode by 88%.

A coupled class-B laser system is presented to obtain a nonlinear emitter. Its bistability was theoretically predicted, and numerically illustrated to demonstrate by a typical bistable curve diagram. The bistable system exhibits some typical nonlinear dynamic behaviours, such as hyperchaos, quasi-period as well as coexistent scenarios, and shows a route to a single-period away from hyperchaos. The hyperchaotic states are diagnosed to find by Lyapunov exponent. The hyperchaotic four-scroll strange attractor was illustrated to be characterized by ergodicity, complexity, and randomness. The result has a reference value for a bistable optical device, a hyperchaotic emitter, and their applications.

Proportional integral derivative (PID) controllers are widely used across various industries. This paper presents a new modified PID controller based on integer origin raw data, which are equivalent to classic PID controller based on floating-point actual values. These new formulas presented in new PID controller provide a mathematical approach to the ‘Classic PID Formula’, ‘Subtractor Formula’ and ‘Scaling Formula’, which form the basis of classic PID controller. The approach integrates these three formulas and separates them into integer and real value by applying the properties of associativity and commutativity. This method uses origin raw data as input to perform integer-based computation and performs floating-point operations once. This resulted in faster computation time and energy savings, while showing accuracy comparable to the existing double precision formulas.

This paper first presented a novel kind of modified curved nails for building the gap waveguide. By controlling the curved degrees, the realized gap waveguide can achieve a wider electromagnetic band gap range. Subsequently, a groove gap waveguide resonator based on this was proposed that can offer the advantages of miniaturization and high unloaded quality (Q_u) values, which is a good candidate for designing low-loss filters. To further reduce the footprints while maintaining the high Q_u, the concept of the folded waveguide was deployed here to construct the so-called folded groove gap waveguide resonator for the first time. Then, a 4-pole filter based on the folded groove gap waveguide resonator was designed to validate the possibilities. The designed filter showed comparable performance as its counterparts of half-mode gap waveguide resonator but with smaller. For rapid prototyping, 3D metal printing was adopted to fabricate the filter concerning its periodical nail structures. The printing quality is acceptable, and the tested results agreed well with the simulated ones.

This study proposes an improved ResNet18 model based on cloud platform and hyperspectral image to identify crop seeds. Hyperspectral images are preprocessed by moving average method (MA) and standard normal variable transformation (SNV) to reduce spectral data interference. The successive projection algorithm (SPA) is used to select characteristic wavelengths and reduce the band dimension. The heterogeneous convolution and channel attention mechanism (CAM) are used to reduce parameters and computation load of ResNet18. Image recognition with improved ResNet18 takes 4.4 s with 4.2 s improvement over the original ResNet18 and saves 2808 KB memory. Accuracy has increased from 93.1% to 96.7%. The improved ResNet18 was deployed on Alibaba Cloud ESC server with uWSGI, Nginx and flask to achieve high concurrency and fast recognition. For single-variety seed identification, the average time reduced to 0.56 s, with an 87% decrease and accuracy is 96.3%. For mixed seeds of five types, accuracy is 90.22% with a time consumption of 0.88 s. The results demonstrated that the proposed method exhibited high effectiveness and accuracy.

Spectre class of transient execution security attacks on modern microprocessors rely on speculative execution. Software Controlled Speculation (SCS) was proposed as a microarchitecture-level defense in the original Spectre paper and has also been adopted by ARM. The idea with SCS is to allow a mode in the microarchitecture, where instructions that read from memory are not allowed to execute speculatively. Errors or malicious fault-injections in the implementation of SCS can still render the microarchitecture vulnerable to Spectre attacks. A formal verification method is proposed that can check the correctness of the implementation of SCS and detect any faults. The method has been demonstrated to be very efficient on two sets of benchmarks and provides accurate detection of implementation faults in SCS.

Wireless sensor networks and nodes are faced with severe constraints in power capacity and lifespan, especially in harsh and cold environments. Electromagnetic radiation energy harvesters serve as a promising alternative power source for sensor nodes. However, the power output from reported energy harvesters remains limited, emphasizing the critical need to reduce power consumption in sensor nodes. Here, a miniaturized, low-voltage, low-power active frequency selective surface solution is proposed for backscatter communication under ice. It is designed for the 2.4 GHz wireless band and can operate under extreme conditions, such as sub-ice environments, requiring only a 3.3 V control voltage and consuming approximately 0.3 $��\mu �W�$ of energy. Experimental results in sub-ice scenarios demonstrate its reliable reflection control characteristics, making it particularly suitable for backscatter communication nodes in wireless sensor networks deployed in harsh environments.

A novel method for blind reconstruction of binary Bose–Chaudhuri–Hocquenghem codes is proposed. Compared to previously reported works, a new approach to find the goal generator polynomial is employed. First, using the feature that each codeword polynomial of a t-error-correcting Bose–Chaudhuri–Hocquenghem code has the same 2t consecutive roots over Galois field, a new set of candidate generator polynomials is introduced. Then, this set in a random situation to find the correct generator polynomial is investigated. Monte Carlo simulations demonstrate the superiority of the proposed reconstruction algorithm compared to the previous methods.