Low-Cost Compact Integrated Rectenna for Implantable Medical Receivers

A frequency reconfigurable miniaturized circular microstrip patch antenna operating in WiMAX (2.5–2.8 GHz) and ISM (2.4–2.48 GHz) frequency bands for the rectenna applications is proposed here. The theory of reconfigurability is employed to switch the operating frequency of the proposed antenna from 2.53 to 2.45 GHz. The electrical length of the radiated circular patch is increased while keeping the overall physical dimension of the antenna constant to provide different current distributions on the radiating patch for the phenomenon of frequency shift. The high permittivity substrate and microstrip transmission‐line feeding mechanism is used to reduce the size of antenna. To demonstrate the reduction in antenna size, a comparison of the proposed antenna with the latest antennas for rectenna applications in literature is presented.

VLSI computing is critical in chip fabrication in today's digital age. Moore's law demands that "the number of transistors on a microchip doubles every two years" in addition to that "the count of transistors employed in a chip size is reduced". As a result, this rule is dictating the electronics industry by reducing chip area, size, and power consumption while simultaneously enhancing chip fabrication strength. The arithmetic circuits are constructed in this work, by boosting the efficiency of circuits by considering die space as a constraint. Overall, arithmetic circuits have a bunch of usages in processing architecture. The XOR gate and multiplexer are utilized in this study to make compressor circuits more efficient by taking into account area, power, and delay. To examine the arithmetic circuit's performance, the load capacitance is customized and the power dissipation across the capacitor is studied.

The open‐circuit voltage of a triboelectric nanogenerator (TENG) increases with the tribo‐charge density and the separated distance between two tribo‐surfaces, which can reach several thousand volts and is much higher than the working voltage required by most electrical devices and energy storage units. Therefore, improving the effective efficiency of TENGs requires reducing the output voltage and enhancing the transferred charges. Here, a multilayered‐electrode‐based TENG (ME‐TENG) is developed in which the output voltage can be managed by controlling the charge flow in a process of multiple (N) steps, which results in N times lower voltage but N times higher total charge transport. The ME‐TENG is demonstrated to work in various modes, including multichannel, single‐channel, and double‐tribo‐surface structures. The effects of insulator layer thickness and total layer number on the output voltage are simulated by the finite element method. The output voltage can be modulated from 14 to 102 V by changing the insulator layer number between two adjacent working electrodes, based on which the 8‐bit logic representations of the characters in the ACSII code table are demonstrated. The ME‐TENG provides a novel method to manage the output power and has potential applications in self‐powered sensors array and human–machine interfacing with logic communications.

This paper proposes an isolated multilevel DC-DC converter topology and modulation scheme to interface the high voltage (HV) battery pack and propulsion inverter in electric vehicles. The proposed topology is based on two switched capacitor networks in a half-bridge configuration. This converter provides bi-directional power flow and outputs multilevel DC voltage at the propulsion inverter side terminal. The multilevel voltage provides a significant reduction in the size of the LC filter and reduces the ripple content in the output voltage. In addition to the reduction in filter size, the proposed converter achieves higher efficiency due to the soft switching of full-bridge side devices connected to the battery bank. The converter modulation strategy and detailed operation during regenerative mode have been presented in this paper. The converter performance is validated through a simulation study and experimental evaluation in a laboratory prototype.

Leukocytic pyrogens, which are frequently called cytokines that are proinflammatory, initiate and enhance the process of inflammatory reactions when tissues are injured. This is an essential biological process causing a high temperature and boosts the defenses of the immune system to infections. Using laboratory mice as the experimental animal, the study sought to ascertain how cold laser stimulation affects the synthesis and release of leukocytic pyrogens, which are important in initiating and intensifying the body’s reaction to inflammatory damage to tissues. The goal of the research was to ascertain the effects of cold laser treatments on the generation and distribution of these crucial components of the immune system’s ability to protect against pathogens. Forty lab mice were used to create standard 1-cm facial wounds. Two groupings of animals have been formed. A continuous 940-nm laser with 500[Formula: see text]mW of output power, 0.8[Formula: see text]cm2 of beam spot area at the target, and instantaneous delivery of an energy density of 187.5 J/cm2 is used to treat the first group. This happens when the mice sustain injuries and the second group serves as a control group. Leukocytic pyrogen initially appeared to be an immunohistochemistry-positive stain throughout laser-treated and untreated control specimens. In the untreated group, the levels of leukocytic pyrogen increased from the beginning to the third day, then decreased for an entire week, and then increased once more after a period of two weeks. Leukocytic pyrogen concentration, on the other hand, showed a significant decline on both the initial and third days following therapy with laser in comparison to those in the control group. The findings of this investigation suggest that leukocytic pyrogen expression could be impacted by therapeutic lasers. Leukocytic pyrogen levels which evolve show the manner in which the cell reacts to inflammatory conditions. This work presented sheds the spotlight on the possible advantages of medical laser therapy concerning leukocytic pyrogen concentrations as well as indicates interesting possibilities for more studies in this field.

A single-inductor dual- output (SIDO) buck converter has recently found applications in hand- held battery-powered electronic devices. The circuit operation and the functional interdependencies among basic converter parameters such as dc gains, transistor duty cycles, and load current levels are much more complicated than those of the single- output counterpart. In this project, a rigorous analysis was conducted to develop dc equations in steady state operation for SIDO converters. More importantly, from the analysis results, a possibility of a new mode of operation, dubbed mix-voltage operation, will be pointed out. In the so-called mix- voltage operation, the converter is capable of working even when the input is lower than one of the two output voltages. In the past, a SIDO buck converter has been used for providing pure-buck outputs, i.e., both output voltages are lower than the input voltage. Therefore, this possibility not only opens up new applications but also extends the operating battery range in existing applications. Experimental results confirmed the dc equations and the mix-voltage conversion of SIDO buck converters.

Solar energy has become a promising renewable energy source due to rising worldwide energy demand and environmental concerns in recent decades. This study examines temperature, solar irradiance, and series resistance (Rs) as internal and external elements affecting solar panel efficiency to optimise photovoltaic (PV) performance. Sunlight increases current and voltage outputs, but incidence angle, air dust, and pollution can reduce efficiency. Therefore, solar panels should be orientated and cleaned often. Open-circuit voltage (VOC), maximum power output (Pmpp), and fill factor (FF) decrease performance at high temperatures. Water cooling or cooling plates can save PV cells from overheating. Finally, Power dissipation across resistance lowers voltage and current output as Rs increases. Preventive maintenance, material selection, and production techniques can lower Rs and maximise efficiency. This research emphasizes the importance of addressing environmental and material factors in solar panel installation and maintenance to achieve optimal efficiency and reliable energy generation in PV systems.

In this study, we fabricated a flexible 3D mesh structure with periodic voids by using a 3D lithography method and applying it to a vibration energy harvester to lower resonance frequency and increase output power. The fabrication process is mainly divided into two parts: three-dimensional photolithography for processing a 3D mesh structure, and a bonding process of piezoelectric films and the mesh structure. With the fabricated flexible mesh structure, we achieved the reduction of resonance frequency and improvement of output power, simultaneously. From the results of the vibration tests, the meshed-core-type vibration energy harvester (VEH) exhibited 42.6% higher output voltage than the solid-core-type VEH. In addition, the meshed-core-type VEH yielded 18.7 Hz of resonance frequency, 15.8% lower than the solid-core-type VEH, and 24.6 μW of output power, 68.5% higher than the solid-core-type VEH. The advantage of the proposed method is that a complex and flexible structure with voids in three dimensions can be relatively easily fabricated in a short time by the inclined exposure method. As it is possible to lower the resonance frequency of the VEH by the mesh structure, use in low-frequency applications, such as wearable devices and house appliances, can be expected in the future.

Initial agglomeration of non-wetted solid particles in high temperature melt

A non‐isolated DC–DC converter with high‐voltage gain and low‐voltage stress on switches is proposed in this study. For absorption of energy n stages of diode–capacitor–inductor (D–C–L) units are used at the input that results in higher voltage gains. Actually, the proposed converter generalises the voltage lift circuit and combines it with a voltage multiplier cell. Therefore comparing to structures with one stage of D–C–L unit, it will be feasible to achieve supposed voltage gain at lower duty cycles. Lower values of duty cycle will result in increasing of converter controllability and increasing of operation region. The generalised analysis of the voltage and current stresses of the semiconductors and power components is carried out. The circuit performance will be compared with other solutions that were previously proposed for voltage step‐up in the terms of voltage gain, switch and output diode voltage stress and number of components. The carried mathematical analysis and circuit performance are validated through both simulation and experimental results that match each other reasonably well.

Charge pump power converters in integrated form are used to produce different d.c. levels. The output voltage, voltage ripple, and required chip area (total capacitance) are some of the most significant performance factors that could have an impact on circuit operation. A trade-off between the aforementioned factors is necessary to improve these parameters. In this study, genetic algorithm (GA) is used as an optimization technique to produce the best design that meets predetermined criteria. The genetic algorithm is used to minimization the chip area (total capacitance) by increasing the number of stages. It is established Constraining factors also include other performance metrics. The obtained parameter values preserve performance while meeting the fitness function's minimal requirements, which include the needed chip area (total capacitance).

Output voltage, output current and line current waveforms in a symmetrically pulse width modulated (SPWM) ac chopper are analyzed for harmonic content, displacement factor, distortion factor, power factor and efficiency. The results are compared with those of phase controlled ac chopper circuit to assess the superiority of SPWM ac chopper. A novel SPWM ac chopper with minimum number of active components is presented. The circuit operation and the design considerations are discussed.

The authors present a novel type of zero-voltage-switched (ZVS) push-pull DC-DC power converter with two synchronous rectifiers in the secondary circuit. ZVS is realized using the magnetizing current of the transform as a current source during the commutation. The output voltage is controlled by pulsewidth modulation (PWM) with a constant switching frequency. The circuit operation is described using equivalent circuits. The steady-state and dynamic characteristics are analyzed. The characteristics were confirmed experimentally.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

A new method for reducing the harmonics involved in the output voltages of a double-connected inverter is proposed. By adding four auxiliary switching devices and an interphase transformer with a secondary winding to the conventional 12-step inverter, output voltages of the proposed circuit can produce almost the same waveforms as a conventional 36-step inverter. In this paper, circuit performances and output voltage waveforms are discussed, and optimum parameters are derived. The effects on harmonic reductions are then clarified by theoretical and experimental results, and the ratings of system components are investigated. >

In this paper, we propose an improved multi-level voltage source inverter whose output harmonic components can be effectively reduced regardless of simple construction. It is based on the neutral-point-clamped (NPC) inverter. The input DC source is divided into six sections and an auxiliary circuit composed of six switching devices and four clamping diodes are added into the conventional NPC inverter. By controlling the auxiliary circuit appropriately, quasi 24-step voltage waveforms can be outputted from the proposed inverter though it has no output transformers. In this paper, the circuit performances are described and the output voltage waveforms are derived theoretically. The circuit constants and the control parameters for decreasing the output harmonics are discussed. It is made clear that the proposed inverter can be performed with the same output distortions approximately as the conventional 24-step inverter with 24 switching devices and the heavy output transformers. Moreover, in order to adjust the output voltages, the step width control and the PWM control are investigated theoretically and experimentally.