Broad Frequency Spectrum Research Articles

An Ultra-Broadband Conductor-Backed Coplanar Waveguide with Sine Edges

In this paper, a conductor-backed coplanar waveguide with sine edges (CBCPW-SE), consisting of a conductor-backed coplanar with periodic sine edges supported by a dielectric substrate, is proposed as a promising new transmission line (TL) at millimeter-wave and terahertz frequencies. This configuration offers a distinct advantage by maintaining a constant input impedance of 50 Ω across a broad frequency spectrum, eliminating the necessity for any additional impedance matching transitions, thereby enhancing the overall efficiency and simplicity of the transmission system. To verify the design, the CBCPW-SE was fabricated and measured. The measurement results demonstrate that, from 10 MHz to 100 GHz, the insertion loss is less than 0.1 dB/mm and the reflection coefficient is better than −10 dB. The measured S21 (dB) for a 50 mm-long CBCPW-SE section is less than −5 dB from 10 MHz to 100 GHz. The measured group delay per unit length of the trace is 3.4–5 ps, ranging from 10 MHz to 100 GHz. Moreover, the measured group velocity dispersion (GVD) approaches zero, signifying the minimal temporal spreading of the signal components, a crucial aspect for maintaining signal integrity and facilitating high-speed data transmission.

Preparation and investigation of structural, optical, and dielectric properties of PVA/PVP blend films boosted by MWCNTs/AuNPs for dielectric capacitor applications

With the rising global energy demands, there is a pressing need for the invention of efficient and reliable energy storage systems. This research centers on the creation and analysis of flexible dielectric capacitors composed of polymer nanocomposites (PNCs), incorporating a blend of polyvinyl alcohol (PVA) and polyvinyl pyrrolidone (PVP) as the base polymer, with multi-walled carbon nanotubes (MWCNTs) and gold nanoparticles (AuNPs) serving as nanofillers. The AuNPs were produced through an environmentally friendly synthesis method. Films made from PVA/PVP blended with MWCNTs and AuNPs were fabricated using the casting approach. Various characterization methods, including TEM, XRD, FTIR, and UV–Vis spectroscopy, were utilized to evaluate the samples. A detailed analysis of their electrical/dielectric characteristics was conducted. XRD analysis revealed a significant decrease in crystallinity from 55% for the pure PVA/PVP blend to 37% for the 1.6 wt% nanofiller composite, indicating increased amorphous content, which facilitates better ion mobility. FTIR confirmed strong interactions between the polymer matrix and nanofillers, with intensified vibrational peaks pointing to enhanced molecular dynamics. UV–Vis spectroscopy demonstrated a red shift in the absorption edge, and Tauc plot analysis showed a reduction in the indirect/direct optical band gap from 4.84 eV/5.68 eV for the pure blend to 4.26/5.35 eV for the nanocomposite with 1.6 wt% nanofillers. The addition of nanofillers resulted in improvements in their dielectric features, which exhibited a significant performance improvement, with the dielectric constant (ε′) reaching approximately 1100 at low frequency for the 1.6 wt% nanofiller sample, compared to 9 for the pure blend. Additionally, the dielectric loss (ε'') and tangent loss (tan δ) were reduced, with tan δ showing a decrease from 15 for the pure blend to 2 for the 1.6 wt% nanofiller composite at low frequency, indicating enhanced dielectric efficiency and reduced energy dissipation. The capacitors' functionality was assessed through capacitance-frequency and conductance-frequency analyses. The capacitors exhibited stable high capacitance across a broad frequency spectrum, making them alternatives for energy storage solutions.

A comparative investigation of neutron and gamma radiation interaction properties of zircaloy-2 and zircaloy-4 with consideration of mechanical properties

Abstract This study has established the radiation shielding efficacy of zircaloy-2 and zircaloy-4 over a wide spectrum of energy levels. Using the Monte Carlo N-Particle (MCNP) method, the gamma and neutron transmission factors (TF and nTF) were calculated for various energy levels. Zircaloy-2 demonstrated the highest gamma-ray absorption capacity and the lowest neutron absorption capacity among the investigated alloys. The results indicate that zircaloy-2 and zircaloy-4 have nearly the same neutron transmission characteristics. Although many studies have examined the structure and physical characteristics of these materials, there has been a lack of Monte Carlo simulations to comprehensively investigate the correlation between gamma absorption, neutron absorption parameters, and mechanical qualities. This research aims to examine the ability of zirconium and its zircaloy-2 and zircaloy-4 alloys, which are critical materials used in the nuclear industry, to absorb gamma and neutron radiation over a broad spectrum of frequencies. According to the results, zircaloy-2 has the best ability to absorb secondary gamma rays and the highest level of resistance to them. Despite the minimal disparity in the nTF between the two alloys, simulation results have shown that zircaloy-2 has a higher level of neutron transmittance. These results have the potential to expedite the development of novel materials with enhanced attributes for various applications.

Analysis and suppression research of high lift device noise based on large aeroacoustic wind tunnel test

The exterior noise of large aircrafts is an important aspect for the airworthiness certification. The high-lift device is one of the key noise sources for large aircrafts, thus the analysis and reduction of high-lift device noise is important and meaningful. Based on the 5.5m×4.0m Aeroacoustic Wind Tunnel and a half model for the aeroacoustic study of large scale aircrafts, the high-lift device noise properties were studied experimentally. First, the experimental platform, the test model, the test system and noise reduction design were introduced. Then, based on the experimental results, the noise characteristics of the high-lift devices were analyzed. The effects on the noise from the angle of attack and the wind speed were compared. The effects on the high-lift device noise from the noise reduction design on slat and flap were investigated. The results show that, the high-lift device noise has a broad frequency spectrum, with some peak frequency components. As the angle of attack is increased, the noise of the model is generally increased in the medium to high frequency range. With the wind speed increased, the noise is increased dramatically, and the frequency spectra keep a good similarity. The peak noise is suppressed by the noise reduction design.

Enhanced breast tumor localization with DRA antenna backscattering and GPR algorithm in microwave imaging

With the rapid rate of increasing breast cancer cases across the globe and restrictions of existing early stage detection techniques, microwave imaging based cancer and malignant cell diagnosing methodology is finding its way. Microwave imaging technology has higher accuracy of detection in the variation of tissue properties. In this article, a dielectric resonator based wide band antenna is designed and investigated for microwave imaging (MWI) of early breast cancer detection due to its improved accuracy. The designed antenna has compact size, broad frequency spectrum, high gain and broadside radiation characteristics. To attain the wider bandwidth from (6.5 GHz–12.5 GHz), two rectangular shaped dielectric slabs are used. Wide band microwave frequency band supports the high resolution images. A C-shaped defected ground structure is used to tune the impedance matching. Dielectric resonator based antenna has higher gain and reduces the squints in antenna impedance. Two-asymmetrical dielectric slabs contribute in the excitation of different resonating modes which in turn enhance the bandwidth. It also contributes to excite multiple resonance mode that in turn enhance the bandwidth. Antenna performance is first numerically and experimentally verified in free space. Then, simulation based performance is examined for the microwave imaging. Numerical phantom with equivalent tissue properties is designed with and without the tumor. Unhealthy cells have higher water percentage and larger dielectric constant as compared to healthy cells. It causes the different in the back scattered signal of antenna, which is analyzed to diagnose the tumor or cancer. Here, a maximum deviation of 16 dB is observed in the backscattered signal. Furthermore, surface of the breast tissue is scanned along the x-axis and y-axis at different angels. The collected signals are used to reconstruct the microwave image of the interior. Mean value data of backscattered signals is used to locate the existence of unhealthy cells and GPR algorithm is used to calculate the depth of a 4 mm tumor in breast tissue. Proposed structure has shown efficient performance for microwave imaging.

Investigating the Sound Absorption Properties of Silk Cotton and Other Sound-Absorbent Materials

This research investigates the acoustic properties of various materials to mitigate sound transmission and enhance acoustic environments, focusing on silk cotton, cotton wool, chipped foam, and open-cell polyurethane foam. The study evaluates these materials for sound absorption and reduction, considering sound frequency and material density. Materials were tested for their sound reduction and absorption coefficients, with silk cotton emerging as the most effective across a broad frequency spectrum, particularly below 200 Hz and above 1000 Hz. The research demonstrated that silk cotton, with its high porosity and fine fibre structure, achieved significant sound reduction even at low densities The findings align with theoretical predictions of resonance frequencies, showing a strong correlation (r2 = 0.9988 for the sound box and r2 = 0.9894 for the sound pipe). Sound intensity and sound pressure levels were measured using a sound level meter, and data analysis was conducted using graphing and calculating software. The researcher employed modified laboratory methods to account for loose materials and equipment limitations, validating the use of theoretical equations to estimate sound absorption and reduction properties The study provides some insights into using fibrous materials like silk cotton for noise reduction and acoustic enhancement. These findings have practical implications for improving sound quality in various environments, such as schools, studios, and public spaces, contributing to noise reduction strategies and enhancing auditory experiences.

A Flexible and Optical Transparent Metasurface Absorber with Broadband RCS Reduction Characteristics.

Metasurface absorbers (MSAs) are of significant importance in a wide range of applications, such as in the field of stealth technology. Nevertheless, conventional designs demonstrate limited flexible characteristics and a lack of transparency, hence constraining their suitability for certain radar stealth applications. This study introduces a novel MSA operating in the broad microwave range, which exhibits both optical transparency and flexibility. The structure consists of a flexible substrate made of polyvinyl chloride (PVC), along with a resistive film composed of indium tin oxide (ITO). The proposed structure exhibits the ability to effectively absorb over 90% of the energy carried by incident electromagnetic (EM) waves across the frequency range of 9.85-41.76 GHz within an angular range of 0° to 60°. In addition, to assess the efficacy of the absorption performance, an examination of the radar cross-section (RCS) characteristics is conducted. The results indicate a reduction of over 10 dB across the aforementioned broad frequency spectrum, regardless of the central angle.

Laboratory measurements of water saturation effects on the acoustic velocity and attenuation of sand packs in the 1–20 kHz frequency range

AbstractWe present novel experimental measurements of acoustic velocity and attenuation in unconsolidated sand with water saturation within the sonic (well‐log analogue) frequency range of 1–20 kHz. The measurements were conducted on jacketed sand packs with 0.5‐m length and 0.069‐m diameter using a bespoke acoustic pulse tube (a water‐filled, stainless steel, thick‐walled tube) under 10 MPa of hydrostatic confining pressure and 0.1 MPa of atmospheric pore pressure. We assess the fluid distribution effect on our measurements through an effective medium rock physics model, using uniform and patchy saturation approaches. Our velocity and attenuation (Q−1) are accurate to ±2.4% and ±5.8%, respectively, based on comparisons with a theoretical transmission coefficient model. Velocity decreases with increasing water saturation up to ∼75% and then increases up to the maximum saturation. The velocity profiles across all four samples show similar values with small differences observed around 70%–90% water saturation, then converging again at maximum saturation. In contrast, the attenuation increases at low saturation, followed by a slight decrease towards maximum saturation. Velocity increases with frequency across all samples, which contrasts with the complex frequency‐dependent pattern of attenuation. These results provide valuable insights into understanding elastic wave measurements over a broad frequency spectrum, particularly in the sonic range.

Miniaturised ultra‐wideband circular polarised koch fractal crossed dipole array

AbstractUltra‐wideband (UWB) systems utilise a broad frequency spectrum to achieve high data transmission rates and enhanced precision, creating a demand for specialised UWB antennas. Circularly Polarised (CP) antennas are considered essential for maintaining robust performance under varied environmental conditions. Among them, the crossed dipole is effective for UWB CP applications, but its relatively large size could limit its use in various systems. A miniaturised crossed dipole design employing the Koch fractal structure is proposed and the measurement results are presented. The prototype antenna achieved an effective bandwidth covering 88% of the frequency range from 1.4 to 3.6 GHz. Additionally, a 4 × 4 array using this design was tested in the same frequency band, demonstrating beam‐steering capabilities up to 30°. The proposed antenna has demonstrated effective deployment in diverse communication systems and phased array applications within ultra‐wideband (UWB) CP environments.

Dielectric relaxation and electrical conductivity in lead-free organic ferroelectric diisopropylammonium bromide (dipaBr)

In this communication, we explore the dielectric relaxation behavior of the novel organic salt Diisopropylammonium Bromide (dipaBr), focusing on the universal relaxation law. We conduct dielectric relaxation and conductivity analyses across a broad spectrum of temperatures (325K–443K) and frequencies (20 Hz–20 MHz). The irregularity in peak broadening observed in complex modulus spectroscopy indicates a distribution of relaxation periods with varying time constants, confirming that the relaxation is of the non-Debye type. To interpret the experimental findings, we utilize the Havriliak-Negami (HN) formula in our investigation of dielectric relaxation. The parameters derived from the model are discussed. The relaxation process in the material appears to depend on temperature. The ac conductivity profile follows Jonscher's universal power law, and the relationship between bulk DC conductivity and temperature follows an Arrhenius-like pattern.

Noise Aware Fully Integrated Low Power and Low Inrush Current Fast Transient Response LDO

The complexity of Systems-on-Chip (SoC) designs necessitates robust linear regulator architectures to ensure stable operations and efficient power management in modern devices. In response to this demand, low-dropout (LDO) voltage regulators have emerged as a focal point for their scalability and superior performance across diverse application domains. This paper proposes an LDO linear regulator characterized by high power supply rejection ratio (PSR) and rapid transient response. The design of this LDO emphasizes low power consumption and minimal inrush current while incorporating advanced techniques to enhance PSR and stability across varying frequencies. Despite its compact footprint and low-power profile, this LDO achieves remarkable PSR across a broad spectrum of frequencies. To achieve swift transient response, the proposed design integrates variable biasing and transient boost capacitance. The variable bias structure enhances the slew rate and PSR of the LDO, contributing to its overall performance optimization. Additionally, the strategic placement and utilization of transient-boost capacitance leverage its voltage characteristics to bolster transient response without introducing additional quiescent current, thereby further enhancing circuit stability.

A wideband vibration sensor with piecewise nonlinear and up-frequency coupling strategy for mechanical fault monitoring

Vibration analysis using vibration sensors is an effective method of monitoring mechanical faults. However, most current vibration sensors have a narrow working frequency range and a low-frequency vibration response. Therefore, broadening the frequency band to detect high-frequency vibration signals is imperative. This paper proposes a self-powered vibration sensor based on a broadband hybrid generator (VS-BHG) that incorporates a piecewise nonlinear and up-frequency coupling strategy through collisions between the suspension and fixed part, thereby effectively expanding the operational frequency range. By implementing this strategic approach, the VS-BHG can effectively capture the vibration energy across a broad frequency spectrum ranging from 5 to 38 Hz and exhibit a robust linear response to acceleration within the frequency range of 20–1600 Hz. A machine running state monitoring system based on the VS-BHG is established, enabling the recognition of 16 different running states and fault types in industrial fans with an accuracy rate of 98.38 % using a deep-learning model. This paper presents an efficient and viable method for monitoring broadband mechanical fault.

Broadband Aircraft Noise Attenuation Across Low and High Frequencies Using Structured Materials

Controlling broadband noise throughout the spectrum, from low to high frequencies, is a significant challenge for the aerospace, transportation, and construction industries. Although recent research has focused on low-frequency noise control solutions using acoustic metamaterial designs, the narrow-band resonances of these materials remain a limitation. This paper presents a structured material system which addresses this limitation by proposing a parallel assembly of structured materials, enabling broadening of the resonance frequency band from low to high frequencies. The study involves an arrangement of structured metamaterials and Helmholtz Resonators embedded in a layer of glass wool. By meticulously grouping individual resonant frequencies, the proposed assembly effectively attenuates noise over the frequency range of interest. The present research contributes to the development of lasting solutions for aircraft noise across a broad frequency spectrum, showing promising potential for significant noise reduction within practical constraints.

Microwave gain-assisted optical limiter in molecular magnets

We investigate the optical properties of a crystal of molecular magnets within the microwave frequency range. It is shown that in the presence of a static magnetic field and applying a coupling laser field in the microwave region, reverse saturable absorption in the microwave domain can be induced in molecular magnets. Notably, the intensity and detuning of the coupling laser field are shown to exert significant control over electromagnetically induced optical limiting (OL). Thus, the OL behavior can safeguard the active sensors in seekers against the saturation as they approach microwave sources. What we believe to be a novel optical limiting phenomenon is introduced, wherein the crystal amplifies noiselessly weak input microwave fields in the linear region of the optical limiter while attenuating intense input fields. Consequently, these findings suggest the potential for actively controlling radars or seekers by exploiting a gain-assisted optical limiter to detect microwave sources with weak signals. The static magnetic field, acting as a pivotal parameter, significantly influences the attainment of OL performance across a broad spectrum of microwave frequencies. We anticipate that the outcomes of this investigation could be applied in microwave photonics to enhance the ranging capabilities of missile seekers or radars via the identification of weak signal targets. Additionally, the research highlights the protective capabilities of microwave sensors against high-power microwave signals. Finally, the open aperture Z-scan technique is employed to confirm the induced gain-assisted optical limiting behavior in molecular magnets.

Electrostatic microturbulence in W7-X: comparison of local gyrokinetic simulations with Doppler reflectometry measurements

The first experimental campaigns of Wendelstein 7-X (W7-X) have shown that turbulence plays a decisive role in the performance of neoclassically optimized stellarators. This stresses the importance of understanding microturbulence from the theoretical and experimental points of view. To this end, this paper addresses a comprehensive characterization of the turbulent fluctuations by means of nonlinear gyrokinetic simulations performed with the code stella in two W7-X scenarios. In the first part of the paper, the amplitude of the density fluctuations is calculated and compared with measurements obtained by Doppler reflectometry (DR) in the OP1 experimental campaigns. It is found that the trend of the fluctuations along the radius is explained by the access of the DR system to different regions of the turbulence wavenumber spectrum. In the second part of the article, frequency spectra of the density fluctuations and the zonal component of the turbulent flow are numerically characterized for comparisons against future experimental analyses. Both quantities feature broad frequency spectra with dominant frequencies of O(1)–O(10) kHz.

Tunable metamaterials with carrier-induced effective permittivity for active control of electromagnetic fields in semiconductor manufacturing device

Precise control of electromagnetic fields is critical in many advanced manufacturing processes, such as those used in the semiconductor industry, where device performance relies on precision and uniformity. Here, we introduce a solution to control electromagnetic fields via permittivity modulation without the limitations of resonance-based approaches, through a patterned semiconductor enabling permittivity tuning via carrier-density modulation. This carrier-responsive metamaterial (CRM) exhibits frequency-independent performance over a broad frequency spectrum and significant permittivity tunability through controlled semiconductor conductivity. Furthermore, the conductivity response and the tuning range can be easily modulated through the variation of semiconductor materials and geometrical parameters. We present an intuitive model that explains the relationship between the CRM’s structure and properties, including its effective permittivity and loss tangent. Supported by comprehensive simulations and experimental validations, our findings show that the effective permittivity can be increased by over 3.5 times with low dielectric loss across a wide frequency range. As an application, we explore the CRM’s potential in plasma control, revealing its ability to influence plasma density nearly 30% by modulating its effective permittivity, exhibiting CRM’s versatile functionality and potential impact across diverse technological domains.

Investigations of high-Performance Ultrasonic Transducers based on PMN-PT Single Crystals

Ultrasonic transducers for NDE applications are commonly based on Lead Zirconate Titanate or PZT, an inorganic compound and ceramic perovskite material. Until now the advantages of PMN-PT are used in medical applications, but are not implemented in NDE. Lead Magnesium Niobate-Lead Titanate (PMN-PT) is well known for its high sensitivity and broad frequency spectrum. While conventional PZT materials have an electromechanical coupling factor K33 (a measure of the conversion between electrical and acoustic energy) of about 0.72, PMN-PT materials reach peak values of more than 0.93. For applications with low signal amplitudes, high electronic noise and small transducer elements, the performance of ultrasonic probes can be significantly enhanced by using Lead Magnesium Niobate-Lead Titanate (PMN-PT) instead of PZT. This single-crystal material offers significantly better piezo parameters and leads to a higher sensitivity and larger bandwidth. There is a better depth resolution possible with this transducers as practical tests have shown. Similar to PZT it can also be fabricated in 1-3 piezo- composite technology. In a cooperation between Fraunhofer IKTS, iBULe Photonics, and IFU Diagnostic Systems, PMN-PT ultrasonic transducers are developed and optimized. The performance of phased array probes and single element transducers was measured by a so called PCUS® pro electronic front end from Fraunhofer and compared with equivalent PZT-based probes. As a result various single element and phased array transducers with im-proved performances are available for NDT of typical aerospace materials and applications. These test setups were used to weigh up the advantages and disadvantages, such as achievable precision or costs, for the implementation of a PMN-PT-based UT matrix probe. Based on this, a wiring variant adapted to the PMN-PT was developed and optimised for the matrix setups by pre- assembling the matching layers. The most favourable setup turned out to be bonding the PMN- PT composites to the prefabricated matching layers together with a rigid-flexible PCB frame. This enabled direct wire bonding of 64 matrix elements to the matching PCB pads on the rigid frame.

Atmospheric Noise Measurements in the Garden: Detecting Universalities in Inter-Spheric Waiting Time Statistics

Lightning flashes result in an instantaneous emission of electromagnetic (EM) waves that encompass a broad spectrum of frequencies in the domain of radio waves. The signature of these impulses in the region of the very low frequency (VLF) of radio waves and bellow are called spherics. These impulsive signals traverse great distances in the waveguide between the Earth’s ionosphere and its surface. Due to the abundance of lightnings the lower end of the EM spectrum is dominated by the waveforms of these emission. It is called atmospheric radio noise because of its origin. This article outlines a straightforward approach for capturing spherics activity within the VLF radio wave range. Employing data processing techniques, we pinpoint the timestamps of spherics within time series data. The distribution of inter-spheric times is analyzed across various detection threshold levels. Utilizing recordings spanning two distinct years and seasons, we replicate the established form of the inter-spheric time distribution described in the literature. Notably, we demonstrate that by rescaling the time intervals between spherics with the mean time for a specific recording and given detection threshold, the distributions collapse to a master curve. This universal pattern is accurately characterized by a single-parameter mean-scaled Gamma distribution. Additionally, we note the similarities in the distribution of inter-spheric times with patterns found in earthquake recurrence times.

Sensorless model-based displacement estimator for piezoelectric actuator through a practical three-stage mechanism

Piezoelectric elements (PEMs) are used in a variety of applications. In this paper, we developed a new simple sensorless method for a Piezoelectric Actuator (PEA), which includes piezostack elements and a three-stage amplification mechanism.This research focuses on a piezoelectric actuator that incorporates a three-stage amplification system, where the outcome of one stage serves as the input for the subsequent one. The actuator receives two types of inputs: the voltage applied to the piezoelectric elements and the mechanical load it carries. Its output is defined by the rotation angle observed at the end of the third amplification stage. To indirectly measure the actuator's displacement, a basic external circuit is utilized.The precise movement of these actuators is essential. To circumvent the high costs and limitations associated with highly accurate displacement sensors, there has been a growing interest in sensorless control methods. Certain electrical signals, when measured, can provide an estimation of displacement. However, induced voltage measurements are not effective for piezoelectric stacks. Two more promising measures are the voltage and current of the piezoelectric material.Given that the electrical charge on these actuators closely reflects their displacement with minimal hysteresis across a broad frequency spectrum, it's proposed that displacement can be effectively gauged through current measurements that assess charge.The core contribution of this paper is the introduction and validation, both theoretically and experimentally, of a hybrid algorithm that leverages these two electrical signals to enhance the accuracy of displacement estimates. This was confirmed using a laboratory setup.The primary benefit of this research is the presentation of a straightforward sensorless control algorithm, poised for further exploration within the realm of piezoelectric actuators. The simplicity of both the theoretical model and the sensorless technique facilitates their application across a diverse range of piezoelectric actuators and amplification systems, thereby streamlining the design, modeling, and control strategy development for various actuators.The innovation of this study stems from the application of an uncomplicated sensorless estimation algorithm, coupled with a system-level perspective on piezoelectric actuators. This approach utilizes a simple, adaptable model suitable for a wide array of applications and operational techniques.

Piezoelectric energy harvesting interface with fast open-circuit voltage sampling

This paper presents a piezoelectric energy harvesting interface with fast open-circuit voltage (VOC) sampling and a wide operating frequency range. The fractional open-circuit voltage (FOCV) method is the primary method for maximum power point tracking (MPPT) in energy harvesting systems, due to its easy implementation and relatively low cost. For this method to be efficient, it is necessary to shorten the time required for VOC sampling. To minimize power loss due to VOC sampling, a novel technique is proposed that is capable of sampling the VOC within a time shorter than half a cycle by using an adaptive tracking pulse instead of conventional fixed ones. We also present a peak detector design technique that can operate across a broad frequency spectrum and adapt to diverse vibration scenarios. The proposed technique reduces the duty cycle of the tracking pulse to 0.42%, which is 3.7 times smaller than the conventional 1.56%. The proposed circuit, designed using a 0.35μm complementary metal oxide semiconductor (CMOS) process, consumes just 94nA at 100Hz, 3V VOC, and a 1kΩ load. In a 2~4V VOC range and a 15~500Hz frequency range, the MPPT efficiency exceeds 95%, peaking at 99.9%, and the power efficiency remains over 93%, reaching a maximum of 97.7%.