This paper describes the design methodology of a compact multiband microstrip patch antenna intended for next-generation wireless communication applications. The proposed antenna operates over seven distinct frequency bands: 1.25-1.32 GHz, 2.30-2.44 GHz, 2.50-2.75 GHz, 2.92-3.25 GHz, 3.40-3.65 GHz, 3.70-4.23 GHz, and 4.70-6.0 GHz. These operating bands support a wide range of wireless services, including LTE, 5G communications, Wi-MAX, ISM applications, radar systems, and broadband wireless communications. Multiband performance is achieved through the incorporation of three strategically placed slits in the radiating patch along with a square split-ring resonator (SSRR). By adjusting the dimensions of the slits and the position of the SSRR, the operating frequency bands can be effectively tuned. The proposed antenna occupies a compact footprint of 40 × 40 mm² and consists of a radiating patch, a partial ground plane, and an SSRR structure. Simulation results demonstrate resonant frequencies at 1.3, 2.38, 2.66, 3.0, 3.5, 4.2, 4.9, and 5.7 GHz. Owing to its compact size, multiband capability, and simple structure, the proposed antenna offers advantages in terms of reduced cost, lower system complexity, and miniaturization, making it suitable for modern wireless communication systems.

Due to the high electrical conductivity, relative permittivity, and magnetic permeability of seawater, the propagation behavior of electromagnetic fields differs significantly from that in air. The conductive nature of seawater causes strong eddy current loss and magnetic field attenuation, thereby reducing the effective coupling coefficient and resulting in frequency detuning between the transmitter and receiver coils. Moreover, the marine environment introduces parasitic impedance paths and additional energy dissipation due to the conductive medium, which further decreases transmission efficiency. These unique electromagnetic characteristics make the design and optimization of wireless power transfer (WPT) systems in seawater more complex and challenging than in air, motivating this study to develop and analyze a dual-receiver WPT architecture that improves midrange transmission efficiency under underwater conditions. To address this issue, a single-transmitter dual-receiver (1TX-2RX) WPT system operating in the 300-550 kHz frequency range is designed and implemented. Experimental results demonstrate that, under midrange transmission in seawater, the efficiency of the proposed 2RX architecture improves markedly from 12% in the 1RX system to 25%, while maintaining stable output performance under various receiver coil misalignment conditions. In addition, compared with operation in air, the optimal operating frequency of the 2RX system in seawater shifts leftward from approximately 460 kHz to 410 kHz. To better characterize the impact of seawater on transmission performance, complex impedance and mutual inductance parameters are incorporated into the conventional circuit model, enabling effective representation of the additional losses and coupling attenuation induced by the conductive medium. The predicted load voltage is consistent largely with the experimental measurements, validating the accuracy and applicability of the proposed modeling approach. Overall, this study not only verifies experimentally the feasibility of improving midrange transmission efficiency through a dual-receiver architecture but also establishes theoretically a circuit modeling method suited better for seawater environments, providing useful insights for the design and optimization of marine WPT systems.

Malignant breast tumors differ greatly from healthy tissue in their electrical properties. The specific absorption rate (SAR), which utilizes dielectric properties, including conductivity and permittivity, is a crucial metric for identifying malignant tissue. The use of narrow-band radar technology has shown promise in this regard. In this study, a mono-static, narrow-band, high-directivity printed patch antenna was designed and fabricated on a Rogers RO4350B substrate (ε_r = 3.48, loss tangent = 0.0037) with dimensions of 70 × 55 × 1.52 mm³ and a 50 Ω feed line, operating at 2 GHz to ensure an optimal balance between penetration depth and spatial resolution. A three-dimensional breast phantom (radius 50 mm) was modeled in CST Microwave Studio to evaluate the SAR distribution under microwave exposure. The results consistently show elevated SAR values in malignant regions, with a direct correlation with tumor size, enabling accurate tumor localization based on the coordinates of the maximum SAR. Crucially, the maximum SAR values (4.3708 W/kg for 1-g and 2.4388 W/kg for 10-g tissue) remain within the IEEE controlled-environment safety limits. Powered by the proposed antenna, this SAR-based approach offers a safe, non-ionizing, and potentially effective technique for detecting small or deeply located breast tumors, confirming that diagnostic capability is achieved without any compromise to patient safety.

This paper presents the design, fabrication, and testing of a compact multiband microstrip patch antenna built on a low-cost FR-4 substrate. The antenna combines a meandered radiating line, a defected ground structure (DGS), and two types of metamaterial resonators - a Square Ring Resonator (SRR) and a Circular Complementary Split Ring Resonator (CCSRR), to achieve multiple operating bands in a small footprint. Full wave simulations in CST Studio Suite predict five resonant bands with reflection coefficient S₁₁ below -10 dB over 2.420-8.216 GHz, with a minimum S₁₁ of -22.24 dB at 3.452 GHz and an overall fractional bandwidth of 108.89 percent. To verify the design, a prototype was fabricated and characterised using a calibrated VNA (Vector Network Analyser). Measurements confirm five resonant bands at 1.871 GHz (S₁₁ = -13.81 dB, 182 MHz bandwidth), 2.573 GHz (-10.10 dB, 52 MHz), 3.704 GHz (-10.27 dB, 65 MHz), 5.095 GHz (-12.11 dB, 676 MHz), and 9.957 GHz (-11.14 dB, 182 MHz). Simulated analysis also indicates stable directivity with a peak realized gain of approximately 2.12 dB at higher operating bands. To accelerate design evaluation, an Artificial Neural Network (ANN) surrogate model was trained on the measured S₁₁ data. The ANN attains a root mean square error of 1.38 dB and a coefficient of determination R² = 0.79, providing near-instantaneous S₁₁ predictions with an approximate 96,500× speedup compared to full-wave electromagnetic simulations. The key contribution of this work is the coordinated use of a meander line for miniaturization, a DGS for bandwidth enhancement, and dual metamaterial loading to realize five distinct operating bands on a single, inexpensive FR-4 board. The proposed antennas operating bands collectively support LTE Band 3, 5G New Radio (NR) sub-6 GHz, IEEE 802.11a/n/acWLAN, and X-band IoT applications.

Investigations into the nature of electromagnetic fields produced by dipole sources over homogeneous flat ground or impedance surfaces date back many years. In general, at a long distance r from the source, the near-surface field is mostly contributed by the geometrical optics term (describing the radiation pattern), a guided wave, and the higher-order reactive contribution referred to as the Norton wave. In the special case of a perfect magnetic conductor interface, the first two terms vanish, so the residual Norton wave determines the steepest achievable field decay profile of r^-3/2 (for a two-dimensional horizontal magnetic dipole). In this letter, we reveal that in the presence of a nonlocal metasurface described by the second-order impedance boundary condition, the field decay can be further accelerated by suppressing the Norton wave (approaching the profiles r^-5/2 and r^-7/2 for electric and magnetic fields, respectively). In a proposed practical realization of a nonlocal metasurface, the effect is numerically verified and shown to reduce the edge diffraction effects by 10 dB for the shield diameter of only one wavelength, paving the way toward compact antenna systems.

Dopamine (DA) is a critical neurotransmitter whose abnormal levels are associated with neurological disorders, including Parkinson's disease, Alzheimer's disease, and schizophrenia. The development of sensitive and reliable detection methods is therefore essential for diagnosis and treatment monitoring. Here, we report a phase-interrogated surface plasmon resonance (SPR) biosensor based on a graphene oxide (GO)-functionalized glass/Ti/Ag/Al₂O₃/ZnSe multilayer platform. The high refractive index (RI) ZnSe layer confined the evanescent field through a waveguide-coupled mode, which produced a sharp resonance with a measured FWHM of 0.077°, a Q-factor of 799, and a figure of merit (FOM) of 1527 RIU^-1. The slight broadening relative to the simulated FWHM of 0.034° is consistent with practical fabrication imperfections and beam angular divergence, though sensor performance was not meaningfully affected. The bulk RI calibration with glucose solutions confirmed a phase sensitivity of 4.53×104 deg RIU^-1 and an angular sensitivity of 120.1°/RIU. For DA detection, the ZnSe surface was functionalized with (3-aminopropyl)triethoxysilane (APTES) and GO and then exposed to different DA concentrations from 1 pM to 10 nM. A semi-log linear fit over the range of 1 pM to 1 nM showed a sensitivity of 1.15°/decade (R² = 0.9547), and a Langmuir isotherm yielded a maximum phase shift of 3.74°, a dissociation constant of 10 pM with R² of 0.9987. The limit of detection was 2.17 pM, and the signal-to-noise ratios (SNRs) ranged from 1.12 at 1 pM to 11.52 at 1 nM. The intra-chip coefficients of variation remained between 0.70% and 2.47%. Beyond clinical diagnostics, this platform holds promise for pharmaceutical applications, including drug development, pharmacokinetic/pharmacodynamic profiling, and therapeutic drug monitoring, where reliable small molecule detection is increasingly required. This work, therefore, offers a straightforward, label-free route to picomolar DA detection with a clear path toward real-sample validation and selectivity assessment.

In the study, a hybrid decoupling architecture (HDA) based on metamaterials and metasurfaces is proposed. Subsequently, an enhanced ultra-wideband (EUWB) two-port multiple-input multiple-output (MIMO) array antenna with miniaturization, high isolation, and low coupling is designed based on the proposed HDA. The antenna size is 48 mm × 32 mm × 1.6 mm with an FR4 dielectric substrate, whose relative dielectric constant is 4.4, and loss tangent is 0.005. The simulated and measured results show that the antenna operates from 1.89 to 14.85 GHz with a bandwidth of 12.96 GHz and relative bandwidth of 154.8%. The port isolation S₂₁ is less than -26 dB; the envelope correlation coefficient (ECC) is less than 0.06; the diversity gain (DG) is higher than 9.5; and the maximum gain reaches 7.83 dB. Therefore, the enhanced ultra-wideband two-port MIMO array antenna designed based on HDA exhibits excellent performance and has broad application potential in various scenarios for wireless communications.

A permanent magnet synchronous motor (PMSM) parameter identification method based on adaptive mean position beetle particle swarm optimization (AMBPSO) is proposed, incorporating the distortion voltage induced by the nonlinearity of the voltage source inverter (VSI) into the parameter set to be identified. An adaptive inertia weighting strategy is designed to improve PMSM parameter identification accuracy and reduce computational time. In addition, the Cauchy mutation average optimal-position strategy is introduced to solve the problem of convergence of the algorithm to a suboptimal solution. Meanwhile, the beetle antenna search (BAS) algorithm is integrated with the improved particle swarm optimization (PSO) strategy, which effectively enhances the particle's dynamic perception of the environment space during the iterative process. The proposed AMBPSO strategy enables each particle to update its speed based on its individual historical optimum, population global optimum, and the beetle tentacle gradient search ability in the iterative process, realizing adaptive exploration of the solution space. Simulated and experimental results demonstrate that, in comparison to traditional PSO, the identification results after distortion voltage compensation are more accurate, and the proposed method significantly enhances identification precision and accelerates convergence speed.

The rapid advancement of wireless communication technologies and the Internet of Things (IoT) has led to a substantial demand for energy-efficient and miniature antennas for short-range wireless data communication This paper presents the design, fabrication, and experimental authentication of a small, ultra-thin, microstrip patch antenna operating at 2.4 GHz for ZigBee-based IoT applications. The antenna was designed on a cost effective FR4 epoxy substrate with dimensions of 20 × 40 × 0.8 mm³, facilitating easy integration into compact sensors and embedded devices. A step-by-step parametric optimization methodology was employed to analyze the impact of various evolution phases, ground plane length and slot width of the proposed antenna on S₁₁, peak gain, and radiation efficiency. These parameters were evaluated via simulation and authenticated by laboratory measurements. The results exhibit good impedance matching with a measured S₁₁ of -41 dB and a bandwidth of 150 MHz for the ZigBee network. The antenna achieves a measured peak gain of 2.46 dBi, as well as 79% of radiation efficiency. To substantiate practical implementation, the antenna was integrated with a ZigBee-enabled network, and over-the-air (OTA) experiments are demonstrated using Received Signal Strength Index (RSSI) measurements. The results verify the short-range communication suitable for IoT-based network systems. The proposed design offers a miniature, low-profile, and cost-effective antenna solution for modern ZigBee-enabled IoT architectures.

During the switching transient process of high-frequency devices, such as gallium nitride and silicon carbide, an increase in switching frequency will lead to an increase in the distributed distributed leakage inductance (existing between each coil turn and each layer, as well as magnetic flux leakage) and capacitance values (existing between each turn and each layer of each winding, between different windings, and between the winding and the shielding layer). These parasitic parameters will generate sharp voltage peaks, increase power loss, and even cause surge currents and oscillations. To address these issues, this paper proposes an equivalent power-loss model based on a six-layer planar transformer. By designing interleaved coils and introducing variable impedance parameters X_{1-2; 11-14; 21-24}, d_{1-2; 11-14; 21-24}, and S_{1-2; 11-14; 21-24}, this high-frequency transformer can reduce leakage inductance while increasing excitation inductance, thereby significantly reducing the total power loss of the high-frequency transformer. The optimization design of the high-frequency transformer and the analysis of power loss are of great significance for improving the efficiency of high-frequency DC-DC power supply systems.

To meet the multi-band coverage requirements of 5G smartphones, this paper presents a dual-band antenna pair with high isolation. Based on the principle of mode orthogonality, a T-shaped dual-arm antenna and a bent-loop antenna are integrated within the smartphone frame, enabling excitation of multiple in-phase and anti-phase modes across the two target frequency bands. Under closely spaced arrangement and without requiring additional decoupling structures, the antenna pair achieves superior isolation exceeding 20 dB. A multiple-input-multiple-output (MIMO) antenna array, formed by symmetrically arranging four such antenna pairs, covers the 3.4-3.6 GHz and 5.1-5.76 GHz bands. The isolation across both bands remains better than 15 dB, with efficiencies exceeding 70% and 72%, respectively. The array supports 5G n77/n78 and Wi-Fi frequency bands, and the envelope correlation coefficient (ECC) between ports is below 0.04, demonstrating favorable spatial diversity performance. The proposed MIMO antenna array features a compact form factor and excellent isolation isolation, enabling multi-antenna integration, dual-band operation, and self-decoupling within a limited volume. This design provides a technical reference for future multi-band, multi-antenna system development in 5G mobile terminals.

A dual-stator flux reverse motor (DS-FRM) has the advantages of simple rotor structure and high output torque. However, there is still a problem of high torque ripple. A DS-FRM with irregular Halbach array is proposed in this paper. A small piece of tangentially magnetized permanent magnet (PM) is placed between two radially magnetized PMs. Then, the Multi-Objective Genetic Algorithm (MOGA) combined with the response surface method (RSM) is used to optimize the key parameters of the motor. The results show that, compared with the conventional motor, the proposed model achieves a torque increased to 11.51 N·m and a torque ripple reduced to 2.56%. Therefore, this study provides a feasible scheme for DS-FRM.

To address output current over-limit issues, power oscillations, and degraded transient stability in virtual synchronous generators (VSGs) under asymmetric faults, this paper proposes a variable-weight virtual-impedance-based current balancing control strategy for quasi-Z-source inverter-based VSG (qZSI-VSG) systems. First, a detailed mathematical model of the qZSI-VSG is established to analyze the influence of key parameters on the system's dynamic behavior. By leveraging the VSG operating characteristics in the dq reference frame, a negative-sequence current reference generation method is subsequently developed to effectively suppress negative-sequence components under various unbalanced grid conditions. In addition, a PI controller is introduced to regulate active and reactive power deviations, enabling online calculation of adaptive weighting factors for real-time adjustment of the virtual impedance. This mechanism improves both current balancing performance and transient response. Experimental results verify that the proposed strategy can significantly reduce negative-sequence currents and power oscillations, thereby enhancing the transient stability of the system during asymmetric faults and demonstrating its feasibility and effectiveness.

To address the inherent significant average torque degradation in conventional Axial Flux Permanent Magnet (AFPM) machines when the pole-shift method is employed for cogging torque suppression, this paper proposes a novel Elliptical-Cut Rotating Compensated Halbach Pole Axial Flux Permanent Magnet (EC-RCHP AFPM) machine. The proposed machine suppresses cogging torque via elliptically cut rotating poles and compensates for the induced torque loss by introducing dedicated compensating Halbach auxiliary poles. First, the rotor topology of the proposed machine is presented, and an equivalent surface current model is established to elucidate its operating mechanism. Second, sensitivity analysis and response surface methodology are adopted to investigate the correlation between design parameters and performance responses, and the optimal parameter combination is obtained under given constraints. Finally, the electromagnetic characteristics of the proposed machine are comprehensively analyzed through three-dimensional finite element analysis (3D-FEA). The results demonstrate that compared with the conventional machine, the EC-RCHP AFPM machine reduces cogging torque by 54.9%, increases average output torque by 1.8%, and lowers torque ripple to 6.12%, effectively resolving the fundamental trade-off between cogging torque suppression and torque output retention.

CubeSats deployed into Low-Earth Orbit (LEO) are continuously subjected to cyclic thermal loads and power-system degradation. Replicating these stresses through traditional space qualification is resource-intensive, placing it beyond the reach of most academic teams. Stratospheric High-Altitude Balloon (HAB) platforms offer a cost-effective pre-qualification pathway; however, no previous work has provided a rigorous, analytical method for mapping the stress accumulated during a balloon flight to an equivalent fraction of LEO stress. This gap prevents defensible claims of environmental fidelity. This paper introduces the High Altitude to Low Earth Orbit Correlation Index - Thermal and Power (HLCI-TP), a physics-based composite metric comprising three independently computed sub-indices: thermal fatigue (Coffin-Manson model), electrochemical battery degradation (Arrhenius model), and Ultraviolet (UV) fluence (Beer-Lambert model). Each sub-index quantifies the fraction of a 30-day LEO reference stress budget reproduced during a balloon mission, and the three are combined via a weighted linear sum. The UV sub-index is grounded in the Beer-Lambert electromagnetic attenuation law, directly connecting the framework to the quantification of solar ultraviolet irradiance - a component of the electromagnetic spectrum - at stratospheric altitudes. For a 24-hour reference mission at 35 km, the computed sub-index values are R_T ≈ 1.63 × 10^-4 (thermal), R_P ≈ 2.0 × 10^-6 (electrochemical), and R_U ≈ 9.92 × 10^-3 (UV), yielding a composite HLCI-TP score of 2.07 × 10^-3, which falls within the ``minimal screening'' band. This result is robust across three distinct weighting configurations (factor-of-three spread), a 10,000-sample Monte Carlo uncertainty analysis, and across the full practical range of mission durations (6-48 hours). The framework is further corroborated by applying Rainflow cycle counting to real GPS altitude data from the PMC-Turbo stratospheric balloon mission (35.7-39.5 km, 134.8 hours), which confirms the minimal-screening classification across all tested durations. These results quantify, for the first time through an analytical framework, that a 24-hour stratospheric flight reproduces approximately 0.016% of the LEO thermal fatigue budget and approximately 1% of the LEO UV-A/UV-B fluence budget. The cost savings relative to full Thermal Vacuum Chamber (TVAC) testing are one to two orders of magnitude. Future work will target orbital calibration, a vibration sub-index, and an open-source web calculator.

A compact, fractal-shaped, triple-band multiple-input multiple-output (MIMO) antenna integrated with a frequency-selective surface (FSS) to improve radiation characteristics is presented in this work. The proposed design employs a fractal-based radiating element to achieve multiband characteristics while minimizing the size. The four-port MIMO configuration is developed from a single-port radiator using an orthogonal arrangement to improve the port isolation. A central square slot is introduced to suppress mutual coupling by interrupting surface current paths, thereby improving inter-element isolation across all operating bands. To enhance the gain, a multi-resonant uniplanar frequency selective surface (FSS) is designed and positioned to act as a partially reflective surface. The FSS unit cell, modelled using an equivalent circuit approach, exhibits three distinct stopbands corresponding to the desired operating frequencies of 2.7-3.5 GHz, 5.5-8.4 GHz and 9.3-10.9 GHz. The combined antenna-FSS configuration, with the overall electrical size of (0.5×0.5×0.235)λ, demonstrates a gain improvement of 3-4 dBi in all bands, without compromising bandwidth. With three frequency bands of 2.5-3.875 GHz, 5.25-6.05 GHz and 8.6-10.6 GHz, the proposed MIMO antenna achieves good MIMO characteristics, making it suitable for modern high-speed wireless technologies including sub-6-GHz 5G (WiMAX), WLAN, and ISM bands.

This paper presents a high-gain substrate-integrated waveguide antenna featuring a narrowly-focused radiation beam with enhanced cross-polarization characteristics, specially designed for precision millimeter-wave radar systems and n-257 band point-to-point 5G wireless applications. The antenna incorporates a novel design with dual radiator slots arranged both vertically and horizontally on the broadside wall of the substrate-integrated waveguide, forming a Non-Intersecting Asymmetrical T-shaped unit cell. This unit cell is periodically distributed to create an eight-element radiator array, thereby improving the antenna's gain and bandwidth. The antenna operates in the frequency range from 27 GHz to 28.54 GHz, thereby covering the n-257 5G frequency band. Moreover, it exhibits a half-power beamwidth of 8.1°, low side-lobe level of -13.3 dB, and cross-polarization discrimination level of 25 dB, making it suitable for high-precision millimeter-wave radar sensing applications. The proposed design provides a peak gain of 10.51 dBi with a radiation efficiency of 84.82%. Moreover, the integration of a dome-shaped polytetrafluoroethylene dielectric lens achieves a peak gain of 12.50 dBi with an enhanced radiation efficiency of 86.35%. The antenna design and simulation were performed using CST Studio Suite, followed by an experimental validation. Owing to its high gain, low side-lobe levels, and a sharply focused main-lobe beam with excellent cross-polarization discrimination, the antenna is well-suited for millimeter-wave radar sensing and point-to-point 5G communication systems.

In optical communications, symbol error rate (SER) is a key indicator of system performance when data is transmitted over optical channels. Improving this rate is a major goal in the design of advanced optical systems, as many factors affect performance, including noise and optical impairments. One mathematical method proven effective for improving performance is the use of Laguerre polynomials. This study investigates the impact of variations in the polynomial parameters regarding Laguerre-Gaussian vortex beam (LGVB) on symbol error rate (SER) under weak, moderate, and strong turbulence conditions. The research uses numerical simulations to analyze the beam's intensity profiles and SER for various parameter combinations. Key findings show that specific parameter pairs yield superior SER performance, reducing error rates. The lowest SER under high turbulence is observed at (3,0) and (2,0) due to their spatially dispersed intensity profiles. Optimizing LGVB's polynomial parameters enhances SER robustness in turbulent FSO systems, offering a practical, non-hardware-based mitigation strategy. Simulation results for (n = 3, m = 0) show that the proposed beam configuration reduces SER to the minimum value compared to other Laguerre Gaussian Vortex beams with different values of radial index (n), and topological charge (m) under identical turbulence conditions (Cn² = 10^-12 m^-2/3). This work provides actionable insights for designing turbulence-resilient optical links, particularly in satellite-to-ground and long-range terrestrial communications.

Manufacturing tolerances introduce unavoidable dimensional deviations in electrical machine components. In the case of switched reluctance linear synchronous motors (SRLSMs), the manufacturing tolerance, Δx, may significantly affect the thrust characteristics. Therefore, a systematic investigation of the impact of manufacturing tolerance, Δx, on the thrust characteristics of a cylindrical SRLSM through finite element analysis and experimental validation is presented. Two mover shafts with different tolerance control strategies, denoted as S45C-01 and S45C-02 were fabricated. Based on the finding, the accumulated tolerances of -562.3 μm and -20 μm for S45C-01 and S45C-02, respectively, were acquired using a vision measuring system. Then, the model that incorporated the accumulating manufacturing tolerance, Δx, was created and simulated. Thrust characteristics were evaluated under both ideal and tolerance inclusive conditions and experimentally measured over a current range of 0.1-1.0 A. The results indicate that neglecting manufacturing tolerance leads to substantial discrepancies between simulated and measured thrust, particularly at low excitation currents, with thrust errors exceeding 200%. When measured manufacturing tolerances are included in the simulation, the thrust error is significantly reduced to below 8.4% for S45C-01 and below 4% for S45C-02, demonstrating close agreement with experimental results. The findings confirm that manufacturing tolerance is a critical factor in accurately predicting SRLSM thrust performance and that tolerance-inclusive modeling substantially improves the reliability of simulation-based performance evaluation.

This research proposes a microwave sensor based on a dual-split-ring-resonator (DSRR) structure designed for the detection of the permittivity of solid samples and defective materials. The DSRR structure was chosen because it has a high-quality factor Q, is highly sensitive to changes in permittivity, and is easy to integrate into a planar substrate. The designed sensor is fabricated using a Rogers RO5880 substrate having a dielectric constant ε_r of 2.2, tanδ of 0.0009, and a substrate thickness h of 1.58; the sensor operates in the frequency range of 1 GHz-2 GHz and adopts a dual-port configuration by observing changes in the transmission parameter S₂₁. The measurements used the perturbation theory method, where the resonance frequency shift occurs when a material is inserted into the sensor area. This sensor area is defined as the location of maximum electric field concentration within the resonator. Polynomial equations are derived for measurements on dielectric materials with known permittivity values ranging from 1 to 9.8. The proposed sensor demonstrates high performance, with a measured accuracy of 99.6%, a normalized sensitivity of 2.6%, and a frequency detection resolution (FDR) of 0.026 GHz. These results indicate that the sensor using the DSRR method with hole integration offers reliable and precise permittivity detection, particularly for detecting defects in materials.